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662 Federal Communications Commission Reports
FCC 62-866
BEFORE THE
FEDERAL COMMUNICATIONS COMMISSION
Wasuineton, D.C. 20554
In the Matter of
Revision or FM Broapcasr Boss, PARTICU-
LARLY A8 TO ÅLLOCATION AND 'TECMHNICAL| Docket No. 14185
STANDARDS
Petition of
FM Unum, Inc.
For changes m FM Station Assignment} RM-94
Rules
First Report AND ORDER
By THE Commission: COMMISSIONER FORD CONCURRING AND ISSUING
A STATEMENT IN WHICH CHAIRMAN MINOW CONCURS.
TABLE OF CONTENTS
Para:
graph
Ke CT EE 1
LU Over-all objectives. 5
Du Mundamental considerations and basic assignment
el 6
‘Gono go” approach; measurements. = 9
Propagation curves to be adopted... à 12
Signal ratios for determining interference. d 18
Channels... U. U UL SS Ds a i 19
22
IV 26
27
36
V
39
46
49
52
> 53
S 54
VI Signals, protected as, and separations- wi 57
Signals for aervige. z 57
Protected areas______ e 59
VII The educational channels_______---.---.-_- a! 67
VIII The Table of Minimum Mileage Separations-___ __ 75
IX Equivalence; terrain factors 76
Terrain factors. -- 5.222.255 shoe da pm 82
40 F.C.C.
FM Broadcast Rules 663
TABLE OF CONTENTS—continued
graph
X Directional antennas and polarization:
Directional antennas ------------------ 84
Polarization Bä 89
XI Questions concerning existing stations 35, 91
Existing stations of great height and power___ 93
Expansion of existing facilities 98
Wholesale channel shifts and deletions 100
Operation with sub-minimum facilities_ = 102
XII Pending and subsequently filed applications_ 104
XIII Canadian considerations. _....._._---------.-_- 105
XIV Other matters:
Assignments and programming; duplication. 107
Operator rules and monitors -------------- 111
Miscellaneous suggestions and arguments____ 112
XV Conclusions and Order. 120
Appendix A Amendment of Part 1
Appendix B Amendment of Part 3
I. Introduction
1. The Commission has under consideration its Notice of Inquiry,
Notice of Proposed Rule Making, and Memorandum Opinion and
Order in the above-entitled matters (FCC 61-883, issued July 5,
1961), and the comments and reply comments submitted in the pro-
ceeding by interested persons. This proceeding was instituted for the
purpose of determining what changes in the FM rules and technical
standards are necessary for the optimum development of this broad-
cast service, and how the expansion of the service can be achieved with
the least amount of delay and burden on the Commission, applicants,
and other parties. Some tentative conclusions were drawn from our
preliminary studies and experience and set forth in the Notice, espe-
cially with regard to the need for a fixed “go-no go” type of process-
ing procedure, new FM propagation curves, and for an over-all plan
designed to make the best possible use of the respective channels in
the FM band (a table of fixed minimum mileage separations between
co-channel and adjacent channel stations was proposed). Specific pro-
posals, in some instances in the alternative, were advanced and out-
lined in the Appendix to the Notice. In addition, questions were
asked about specific matters such as antenna and receiver perform-
ance, and the matter of the extent of AM-FM program duplication
to be allowed was raised.
2. A number of parties submitted comments. These ranged from
views on one or two specific topics, such as duplication of AM pro-
grams on FM stations, to opinions on many of the subjects covered
in the Notice. The parties included such varied segments of the indus-
try as networks, broadcasters, educational organizations, and equip-
ment manufacturers.t Unfortunately, very little supporting data was
1 Parties filing comments in Docket 14185: Gainsville Broadcasting Co., Inc., Gains-
ville, Texas; Radio Station WFAH, Alliance, Ohio; KXTR-FM, Kansas City, Mo:
WOHI and WOHI-FM, East Liverpool, Ohio; WPBC, Minneapolis, Minn.; University of
Connecticut, Storrs, Conn.; KAMA-FM, Dallas, Tex.; WKFM, Chicago, "1. : High
Fidelity Broadcasters, Inc., Bethesda, Md.; Rutgers University, New Brunswick, N. f;
Jampro Antenna Co, Sacramento, Calif.; Western Slope Broadcasting Co., Inc.
40 F.C.C.
664 Federal Communications Commission Reports
submitted by most of the parties. In the important area of station
assignment principles, for example, while some parties made specific
suggestions as to re-shufling of channels among certain large Cities,
no one submitted any specific data, even on a sample basis, showing
possible allocations over an area as a whole. However, the comments
and replies were helpful to the Commission, and have been given
careful consideration in connection with all of the decisions reached,
3. The present document represents the Commission’s conclusions
as to many of the matters raised in the earlier Notice, including adop.
tion of minimum mileage separations between co-channel and adja-
cent channel stations, which will be strictly adhered to as in the tele.
vision service, classification of stations and maximum and minimum
facilities for each class, division of the country into Zones different
from the present Area 1 and Area 2, and similar matters. However.
further consideration of this matter has led us to the belief that the
Jong-term optimum use of this band of frequencies may well be best
insured by a Table of Assignments, assigning particular channels to
individual communities, similar to that in television (see §3.606 of
our Rules).
4, We are issuing simultaneously herewith a Further Notice of
Proposed Rule Making with respect to the concept of such a Table
and the principles and priorities to be used in working it out. Work
on a tentative table has been begun, and it is expected that a tenta-
tive Table will be released shortly. The Further Notice also relates
to other subjects set forth therein.
IT. Over-all Objectives
5. While differing in their recommendations, the commenting par-
ties in general agreed that there is need to examine the FM situation,
with a view to providing for the orderly and efficient development of
that service. No one quarreled with the over-all objectives set forth
in the Notice as those to be pursued in this development, as in the
standard broadcast service= (1) provision of some service to all o£
the nation, or as much as possible; (2) provision of as many program
choices to as many listeners as possible; and (3) service of local origi
to as many communities as possible (see the earlier Notice, para-
KRBEX-FM), Grand Junction, Colo.; Bruce YF. Biring, Duluth, Minn.; KFML-AM and
FM, Denver. Colo. ; Burden Associates, Mount Kisco, N. Y.; Intercollegtate Broadcasting
System, Washington, D.C.; Association of Federal Communications Consulting Engineers,
Washington, DG: Donald J. Lewis, New York, N. ¥.; Meredith Broadcasting Co.,
KCMO-FM, Kansas City, Mo.; National Association of Broadcasters, Washington, D.C;
WIBF, Jenkintown, Pa.; KMLA Broadcasting Corp., Los Angeles, Calif.; WTAX, Inc,
Springfield, lll; American Broadcasting Company; WERG- TV. Inc., Mobile, Ala.;
Washington Post Company: Southern Broadcasting Cor; (KTOD-FM), Sinton, es, `
Havens and Martin, Inc, (WCOD), Richmond, Va.; KCBH (FM), Los Angeles, Calif.;
Columbia Broadcasting System, Inc.; A. Earl Cullum, Jr., Dallas, Tex.; National Broad-
casting Company. Inc.: Radio Corporation of America, New York, N. Y.; Zenith Radio
Corp.. Chicago. UI: FM Unlimited, Inc., Chicago, Ill; Storer Broadcasting Co., Bulletin
Co. (WPBS). Philadelphia, Pa.; Lohnes and Culver, Washington, DC: Time-Life Broad-
east, Inc. (WFBM-TV), Indianapolis, Ind.; WOOD-FM, Grand Rapids, Mich.; KLZ-FM,
Denver, Colo.; Department of Education, Puerto Rico; Group of Licensees of FM sta-
tions (FM broadcasters); WEEN, Inc., Buffalo, N. Y.: Capitol Broadcasting Co., Inc.,
(WRAL PM), Raleigh, N. C.; Concert Network. Inc. (WBCN), Boston, Mass.; National
Association of Broadcasters: King Broadcasting Co. (KING-FM), Seattle, Wash.;
WYZZ%. Wilkes-Barre, Pa.; WUOM, Ann Arbor, Mich (noncom); R. A. Isberg, San
Francisco, Calif.
40 F.C.C.
FM Broadcast Rules 665
graphs 6 and 7). As we pointed out in the earlier Notice, these objec-
tives are in part in conflict with each other, as is true with any
broadcast service where the number of channels is insufficient to meet
the possible demands of all communities. This problem is most sharp-
ly focused by the situation prevailing in the northeast section of the
country. Most of this area, and probably all of it which is heavily pop-
ulated, receives at least one usable FM service, and to this extent our
first objective has been achieved. But FM assignments have been con-
centrated to a great extent in the larger cities and surrounding met-
ropolitan areas, precluding in many instances the making of Class B
assignments, or even lower-power Class A assignments, in other com-
munities in the same area. While this assignment process up to now
has provided the residents of many of the larger cities and metropoli-
tan areas with a plenitude of service to choose from, and thus worked
toward achievement of the second objective mentioned, at the same
time it has worked to prevent achievement of the third objective, pro-
vision of local outlets for as many communities as possible. At pres-
ent it is not possible to provide a first FM station to some sizable
communities in this region, to serve as an outlet for local expression,
although service is available to these communities from stations in
other places. Some larger cities are limited to fewer channels than
their population warrants. Likewise, it appears that achievement of
the second objective—plentiful choice of services—has been hindered
as far as area and populations outside of the immediate vicinity of
the larger population centers is concerned.
III. Fundamental Considerations and Basic Assignment Tools
6. In the earlier Notice herein (paragraph 20) we set forth tenta-
tive conclusions as to two basic concepts which, we believed, might
well be those which should govern future FM station assignments.
The first of these was that any future assignments should be based on
an over-all plan, designed to achieve maximum and optimum use of
each channel and take into account total effect on over-all service,
rather than the present system under which an applicant selects a par-
ticular frequency and (absent conflicting applications or basic quali-
fication questions) generally the only consideration is a _case-to-case
weighing of service gains against whatever interference the proposed
station would cause, individually, to existing stations. The second was
that applications should be considered strictly on a “go-no go” basis,
by which an application will either be granted or rejected depending
on its compliance with fixed rules, without elaborate case-to-case
weighing of various factors as at present. I
7. Our earlier Notice (paragraphs 26 to 29) also set forth specific
proposals with respect to two fundamental tools to be used in future
FM station assignments—the propagation curves to be used, and sig-
nal ratios to be emploved for determination of objectionable inter-
ference, co-channel and up to three channels (600 ke) removed.
8. The concept of an over-all plan is discussed later in connection
with the more specific question of the type of plan to be adopted. As
40 F.C.C.
666 Federal Communications Commission Reports
to the three other basic matters just mentioned, after consideration of
the views expressed we are of the opinion that our earlier proposals
are correct. The reasons for these conclusions are set forth in the fol-
lowing paragraphs.
Need for a “go-no go” approach; undesirability of using
MEASUTEMENES 7
- 9. In our earlier Notice (paragraphs 9, 18, 19) we set forth at
length the reasons leading to our tentative conclusion that future
FM assignments, like television assignments, should be on a “go-no
go” basis, with both potential applicants and the Commission being
in a position to predict, through use of criteria and procedures set
forth in our Rules, whether a particular proposed operation will be
granted or must be denied. The absence of. such a concept in the AM
service necessitates, in many cases, the elaborate consideration of vari-
ous factors on a case-to-case basis in connection with each application.
Service gains must be weighed against losses in each case; populations
must be counted; field strength measurements and often counter-
measurements are submitted to attempt to determine the exact loca-
tion of contours; extent of other service available must be considered,
The controversies over all of these matters often result in long,
involved, and costly hearings. The whole process has Jed to the great
delays and burdens, on the Commission, on private parties, and on
the public, all too familiar in the standard broadcast service. More-
over, the absence of the fixed standards leads to the generation and
filing of marginal applications. S
10. Most of the parties commenting on this question agreed with this
basic “go-no go” concept (although some parties also favored use of
assignment tools, such as field-strength measurements, which would
be difficult to fit into such a system). However, some parties believed
that the Comission should retain “flexibility” even in consideration
of individual cases, op, making grants where warranted even
though the proposed operation would cause interference to existing
stations within their “normally protected” contours (on the theory
that the gains in service would exceed the losses from such interfer-
ence). This argument must be rejected. Nearly a generation of experi-
ence with such “flexibility” in the AM field (a concept embodied in
§3.24(b) of the Rules) demonstrates that, whatever advantages may
accrue therefrom in some individual cases, these are outweighed by
drawbacks, burdens, and delays involved, discussed in the earlier
Notice and summarized in the previous paragraph. Moreover, as a
practical matter such “flexibility,” permitting case-to-case weighing
of gains and losses in connection with each proposed operation, is
incompatible with consideration of other, broader factors which
should be taken into account if the FM service is to experience opti-
mum development—the cumulative effect of a series of new operations
on the service of an existing station or stations, possible later expan-
sion of the facilities of existing stations, possihle other uses of the
channel sought more consistent with our general objectives, the effi-
ciency of the proposed assignment, and, in sum, the general relation-
40 F.C.C.
FM Broadcast Rules 667
ship of the proposed grant to the present and future over-all situa-
tion of the medium. These matters, it appears, must be resolved on
the basis of fixed rules, generally applicable, which can be used by the
Commission, its staff, and by private parties, to determine the dispo-
gition to be made of an application or potential proposal.
11. As to use of field strength measurements, the rules presently
provide for their use in FM assignments (though they are seldom if
ever used), but in the earlier Notice (footnote 9) we proposed to delete
all reference to measurements in the Rules so that assignments would
be made entirely on the basis of propagation curves or data derived
therefrom. The Association of Federal Communications Consulting
Engineers (AFCCE) and some other parties urged that measure-
ments should be used as an FM assignment tool, to make allowance
for terrain variations. The subject of terrain considerations is dis-
cussed later; however, as far as use of measurements is concerned we
must reject the AFCCE’s suggestion and adhere to our earlier pro-
osal. This is because field strength measurements are not an exact
tool. It must be borne in mind that the results obtained by measure-
ments, in a particular situation, will vary with locations chosen, time
of day, season, and method of taking. Even in a particular situation,
involving the same small area and period of time, measurements taken
by one party often indicate that interference would exist, while meas-
urements taken by another party indicate absence of interference—a
phenomenon all too familiar in AM hearings. Consideration of con-
flicting measurements would obviously be completely incompatible
with a “go-no go” approach. Where a complete set of measurements
is properly made, it may give a fairly good idea of a station’s cover-
age area in the absence of interference. But. since the extent of a sta-
tion’s actual service area is usually limited by interference, service
measurements are of relatively little value in the absence of interfer-
ence measurements, and the latter are extremely difficult and compli-
cated to make to an extent sufficient to be useful. Therefore—as in
television—it is preferable to use the propagation curves adopted
here, based on analysis of a large number of measurements.
19. Propagation curves to be adopted, In the earlier Notice (para-
graphs 26 and 27) we proposed to replace the present FM propaga-
tion curves used for determining interference (Figure 1 of § 3.333,
based on groundwave propagation only), with more up-to-date
curves, which among other things take into account tropospheric prop-
agation—using for service and interference respectively the F (50.50)
and F (50,10) curves proposed for low band VHF television (Chan-
nels 2 to 6) in Docket 13340. No party disagreed with the decision to
adopt new curves, and most comments on this matter favored those
proposed. However, the AFCCE suggested that (1) service should be
determined on the basis of an F(50.90) curve, in order to guarantee
a higher quality of service; and (2) for adjacent channel assignments,
that interference should be determined on the basis of the F(50,50)
curve, on the ground that at the shorter distances involved nearly
“steady state” propagation conditions prevail.
40 F.C.
668 Federal Communications Commission Reports
` 13. In our view, our original proposal in this respect (which was
earlier supported by the Radio Propagation Advisory Committee
(RPAC), a government-industry group) is correct. As to AFCCE’s
suggestion concerning use of the (50,90) curve for service, the dis.
tinction between this and our proposal amounts to a difference in the
area to be protected, AFCCE’s proposal amounting to protection of a
smaller area, thus permitting somewhat closer assignments. Imposi-
tion of this unduly high standard as to what constitutes adequate
reception would mean loss, through non-protection, of generally use-
ful service outside of the protected contour, and would unduly limit
stations’ service areas.? TV service is evaluated on the F (50,50) basis
and the same should apply here. In the absence of any good basis
therefor, there is no reason to complicate our rules by addition of a
third curve.
14. As to the idea of evaluating first adjacent channel interference
on an F(50,50) basis, at close-in distances there is relatively little dif-
ference between fields at a particular location as shown by this and
by the F (50,10) curve, and therefore it makes relatively little differ.
ence which is used. At larger distances from the transmitter, there js
a greater difference between the curves, as signal variations create
more of a time factor.’ At these distances the conditions urged by
AFCCE in support of this proposal cease to exist, and, in order to
afford adequate protection from occasional interference it is necessa
to.employ an F(50.10) curve. Therefore, use of the F(50,50) curve
would be inapproprite. It should be added as a general observation,
that both of these AFCCE suggestions would result in minimizing
the extent of protection to be afforded existing stations, so that more
and closer assignments may be made. Adoption of these suggestions
would be inconsistent with our basic decision herein, that (except for
certain stations now operating with great height and power, discussed
below) stations are entitled to a greater degree of protection than that
afforded by present rules, in order to avoid destruction of useful
service. AFCCE’s suggestions must be rejected.
Signal ratios for. determining interference
15. Under the present FM rules (§3.313(b)), objectionable inter-
ference exists where: (1) for co-channel stations, the undesired sig-
nal exceeds 1/10 of the desired signal; (2) for first adjacent channel
stations (200 ke removed), the undesired signal exceeds 14 of the
desired signal; (3) for stations two channels (400 ke) removed, the
undesired signal is more than 10 times the desired signal; and (4)
for stations three channels (600 ke) removed, the undesired signal
is more than 100 times the desired signal. In the July Notice (para-
.
2 AFCCE’s proposal is for protection of existing stations to the 1 my/m contour as
determined by the F(50,90) curve. With respect to adjacent channel assignments this
would mean substantially less protection than that provided either under our present
basic assignment system, or the interim procedure based on the F(50,50) curve.
2 Under present protection principles (based on the 1 mv/m contour) and signal ratios,
for first adjacent channel stations the interfering contour is the 0.5 my/m (54 dbu) con-
tour, For a station operating with 1 kw E.R.P. and effective antenna height of 500 feet,
this contour lies 20 miles from the transmitter under the F(50,50) curve and 21.5 miles `
under the F(50.10) curve. For a station operating with 20 kw and 2,000 feet antenna
height, contour lies 62.5 miles or 71.5 miles from the transmitter, respectively.
40 F.C.C.
FM Broadcast Rules 669
aphs 28 and 29) we invited comments upon the question of whether
these or some other interference ratios should be adopted as the basis
for FM assignments; we did not propose any specific changes.
16. Most of the commenting parties favored maintenance of the
resent ratios, in the absence of persuasive data to the contrary.
Those changes suggested were generally in the direction of higher
ratios—ie., more protection—especially as to first adjacent channel
interference. Zenith and RCA submitted data based on measurements
of their receivers’ performances. Otherwise, relatively little specific
information was furnished. Some parties urged that the present
adjacent channel ratio, while perhaps satisfactory for regular FM
proadcast operations, is not enough to protect multiplexed operations
_-stereophonic broadcasting and subsidiary communications opera-
tion—which involve use of more of each FM channel. Zenith, point-
jng out that the signal-to-noise ratio for stereophonie broadcasting
is about 23 db poorer than for monophonic broadcasting, on the basis
of measurements on its receivers, urges that the desired to undesired
co-channel ratio be raised to 100 to one (40 db), and first adjacent
channel ratio to 20 to one (26 db). Zenith does not recommend any
change in second or third adjacent channel ratios.
17. The limited information submitted, plus data gathered and
repared by the Commission’s staff, persuades us that the present
ratios should not be changed. They are sufficiently accurate for the
system of minimum mileage separations which we adopt herein. As
for stereo and SCA multiplex operations, as Zenith concedes, the
higher protection ratios necessary for such operations are balanced
by the fact that the service range thereof is less than that of regular
¥M service. Therefore, a series of ratios (or spacings based thereon)
affording adequate protection to regular service will also afford ap-
propriate protection to these other types of service.* The spacings
we adopt herein, substantially wider than required under present
practice, will achieve this result.
18. It should be noted that, since we are herein adopting a table
of minimum spacings between stations, there is no longer any need
for interference ratios in the rules. The rules set forth in the Appen-
dix hereto do not contain such provisions.
Channels
19. In the July Notice, we did not propose any change in the basic
FM channel structure—100 channels of 200 ke width each, with the
lower 20 reserved for educational use. We did propose as possibilities:
(1) using a group of 20 contiguous channels for use by low power
Class A stations, instead of the 20 Class A channels now interspersed
throughout the commercial portion of the band; and (2) reserving
4As to the first adjacent channel ratio (which was the one most commented on) one
of the problems in making FM assignments, on the basis adopted herein or any other
basis, is that the two-to-one ratio is a positive one, meaning that first adjacent channel
spacing necessary between stations tends to approach the required co-channel spacing—
a situation substantially limiting the number of FM assignments which can be made.
Raising the ratio above what it is now would make provision of an adequate number of
assignments even more difficult than it is at present, and therefore should not be done
unless a really persuasive showing—much more than anything presented here—is made.
40 F.C.C.
670 Federal Communications Commission Reports
a group of 20 contiguous channels for use by high power “Class ©”
stations, designed for wide area coverage and protected out to a
considerable distance.
20. One party (High Fidelity Broadcasters, Inc.) advanced a
rather elaborate system by which Class A stations would be accom.
modated, not in the regular 100 FM channels at all, but in “inter.
leaved” channels to be located 100 ke from the present frequencies
(Oe, 92.2 me, 92.4 me, etc.). Interference ratios to be applied to these
odd channels were specified, and it was proposed that these stations
operate with vertical polarization. This proposal, as advanced here,
has several deficiencies, and must be rejected. First, we have little
information as to how such a plan would operate, what the correct
ratios should be, and what benefits would be derived from it. No
sample allocation plan was submitted, nor was any showing made
as to the impact of a large number of these stations on Class B and
other assignments. The requirement that vertical polarization be
used would place a severe burden of incompatibility on these stations,
and might well defeat the objective sought. The matter of 100 ke
channeling will be further considered by the Commission.
21. The matter of use of the 20 channels now reserved for educa-
tion is discussed below; for reasons stated we retain the present
reservation.
Channels for use by low power Class A stations
22. Comments expressed both support for and opposition to the
idea of making Class A assignments on 20 channels at one end of the
commercial band, instead of on the 20 channels now assigned for
Class A use, interspersed throughout the commercial band. No spe-
cific showings or analyses were presented on either side. The chief
arguments advanced in favor were: (1) as pointed out in the Notice
(paragraph 93), the making of a large number of Class A assign.
ments would be facilitated if, in general, the only adjacent channel
problems involved were other Class A assignments rather than higher
power Class B stations; and (2) there would be less interferenca
problems with Class B stations. One argument advanced against the
idea was that, if all Class A stations were together at one end of the
band, listeners would tend to ignore them and concentrate on the
Class B stations in the remainder of the band, which, with their
greater facilities and resources, tend to offer more attractive pro-
gramming.
23. Since the Notice was issued, the Commission’s staff has made
studies on this question, with respect to the crowded Northeastern
section of the country, the area constituting television Zone I. These
studies indicate that, for that area, such a shift is not desirable. The
chief problem is the number of Class B stations now assigned on
the 20 channels at either end of the commercial band, which are so
numerous that, for the shift to have any significance, these Class B’s
would have to be shifted to the remaining 60 Class B channels. The
staff’s study indicated that this cannot be done, consistent with any
40 F.C.C.
FM Broadcast Rules 671
sort of appropriate spacings between co-channel and adjacent channel
stations such as those set forth in the Notice. Of 112 Class B stations
jn this area on the lower 20 channels, only 46 could be thus accom-
modated on the remaining 60 channels; 66 could not. For the most
art, the ones which could not be reassigned are those in and around
the large cities of this region. The problem is that these areas in and
around the large cities have more than 15 Class B assignments each,
which has been possible under the present system (which can yield
20 Class B assignments even in the city itself), but would not be
possible with the shift of Class A channels to a contiguous band.
‘Under that system, if proper spacings are to be maintained, no city
and its surrounding area could have more than 15 Class B assign-
ments. The proximity of this area to the Canadian border also pre-
sented some problems.
24, With this number of Class B stations which would have to be
Jeft in the contiguous band, it would be possible to reassign only 43
of the 71 Class A stations in television Zone I which operate on
Class A channels above Channel 240, consistent with proper spacings.
Thus, it appears that the idea of a contiguous band is neither feasible
nor desirable in this portion of the country, which is herein desig-
nated FM Zone I, co-extensive with television Zone I. Likewise, for
the same reasons, it appears inappropriate with respect to that por-
tion of California (south of the 40th parallel) where present assign-
ment conditions are generally similar, and which is herein designated
Zone I-A.
25. With respect to the rest of the country, herein designated
Zone II, by and large the FM band therein is presently less occupied,
and there would not to the same extent be the question of either
superimposing the new channel structure on existing stations or
moving the latter. However, even so, it does not appear that there
is anything to be gained from creating a contiguous Class A band.
Conceivably, it could result in more Class A assignments over-all,
and probably would if towns were distributed in a more or less geo-
metric pattern across the country. But, even in Zone IT, there is often
need for numerous assignments in a particular relatively small area,
In these situations, the potential] Class A assignments under the con-
tiguous band approach is substantially less than where the A chan-
nels are interspersed. Moreover, removing the Class A channels
from their present interspersed positions throughout the commercial
portion of the band would complicate the making of Class C assign-
ments (which in the staff’s work so far has proved more difficult than
making Class A assignments), since all of the Class C first adjacent
channel problems would involve other Class Ca, with the greater
adjacent channel spacing requirement involved.
25a. Two parties (Earl Cullum and High Fidelity Broadcasters,
Inc.) urged that all commercial channels should be used without
s The separations used in the studies were somewhat shorter than those proposed in the
Notice. For co-channel, first adjacent channel, and second and shird adjacent channel,
they were, respectively: between Class B stations, 150, 90, and 40 miles; between Class
pi etations, 70, 35, and 15 miles; and between Class A and Class B stations, 115, 70, and
miles.
40 F.C.C.
672 Federal Communications Commission Reports
distinction as to classes of stations—i.e., low power Class A stations
and higher power Class B or C stations would use the same channel,
This concept we must reject, because it represents an inefficient use
of channels. This is true because unduly wide spacings are necessary
in order to protect the lower power stations from co-channel inter-
ference caused by the higher power operations.
IV. Type of Assignment Plan To Be Adopted for
Commercial Channels
26. As mentioned, we have concluded that whatever plan is
adopted herein as a basis for FM assignments, it must be of a “go-no
go” character, as is the television assignment plan. This does not of
itself determine what kind of plan should be adopted, since an
assignment system might be very simple, or it might involve rela-
tively complex computations and formulas, and still, as long as the
end result is certain, it would meet this test. There are discussed
later herein certain rather radical plans proposed by some of the
parties, which we must reject for reasons stated. The principal alter-
natives, meriting serious consideration, are three: (1) protection of
existing stations to a particular field strength contour, such as
1 mv/m; (2) the type of plan proposed in the Notice, a set of mini-
mum co-channel and adjacent channel mileage separations between
existing and proposed stations (which would almost necessarily have
to be based on assumed maximum facilities for both); and (3) a
Table of Assignments, similar to that formerly used in FM and now
used in television, based on minimum separations but involving the
assignment of particular channels to particular communities.
27. Protection to a, particular contour. Several commenting parties
argued against the Notice proposal and in favor of simply a “go-no
go” principle by which an application would be considered on the
basis of whether or not the operation proposed objectionable interfer-
ence (according to the new curves and present ratios) to existing
facilities. Perhaps the most vigorous proponent of this idea was the
AF@CE, whose proposal is for assignments essentially on the same
basis now obtaining under our interim processing procedure—pro-
tection of existing stations to their 1.0 mv/m contours on the basis of
their existing facilities and those proposed in the application, using
the curves and signal ratios adopted herein, AFCCE proposes to
retain essentially the present rules relating to maximum facilities—
90 kw E.R.P. and 500 feet effective antenna height in “Zone I,” and
no maximum elsewhere—and no minima other than those now in the
rules. Other parties supporting this general concept proposed other
protected contours—e.g., 1 mv/m for Class A, 0.5 mv/v for Class B,
and 0.1 mv/m for Class C stations—and maximum and minimum
facilities along the lines proposed in the Notice.
98. The proponents of this plan, vis-a-vis the mileage separation
concept as proposed in the Notice, argue that this is the way by
which the maximum number of new assignments can be made,
whereas, at least with the fairly wide spacings proposed in the
40 F.C.C.
d FM Broadcast Rules 673
Notice, under a mileage separation scheme relatively few new sta-
tions could -be assigned In areas where there is present or likely
future demand therefor. It is argued that a mileage separation system,
based on maximum facilities, is wasteful of spectrum space and
amounts to protection of often non-existent “service”, since many
stations do not now and likely, for economic reasons, never will
operate with anything approaching maximum facilities. It is also
urged that such a system must necessarily be based on assumed uni-
form terrain conditions and more or less uniform distribution of
cities and population—neither of which conditions in fact exists.
Therefore, it is urged, applications should be evaluated individually,
on a simple “protected contour” standard, such as the 1 mv/m. Those
parties favoring mileage separations as opposed to the “protected
contour” concept (which included the NA D. and the networks)
referred to the pressures for non-complying grants which, it is
believed, a “protectea contour” concept would always entail; to the
possibility of conflict between parties as to the exact location of any
given service or interference contour (even using the curves) ; to
the desirability of giving existing stations leeway to increase their
facilities; and to the general consideration of over-all efficiency.
29. The AFCCE proposal obviously would permit a greater num-
ber of assignments; in fact it may properly be termed a “squeeze-in”
proposal, under which any combination of facilities (no matter how
small), and directional antenna suppressing radiation in particular
directions, would be permitted as long as existing 1 mv/m contours
are protected. It must be rejected, for a number of reasons. First,
there is the consideration of over-all efficiency of channel use. As far
as co-channel and first adjacent channel operations are concerned,
any new assignment creates interfering signals over much greater
distances than the extent of its service are, Abus creating islands
of service in the midst of seas of interference. If protection 1s only to
the 1 mv/m contour of existing stations, service outside that con-
tour (which many stations render) will be destroyed. There comes
a point of diminishing returns beyond which additional assignments
on a channel, even though nominally protecting the 1 mv/m contour
of existing stations, result in over-all inefficiency of use. Second, this
plan would merely tend to perpetuate an already undesirable situa-
tion, by encouraging the “squeezing in” of numerous assignments
operating with near-minimum facilities—an inefficient use of chan-
nels, especially those designed for use by medium or higher power
stations. Third, existing stations (both those now in existence, and
those which might be authorized from now on under such a system)
would be forever limited to their existing facilities—often the small
and (from an assignment standpoint) inefficient facilities referred to
above. Especially now that FM shows signs of developing an
economic base sufficient to support relatively large scale operations,
we do not believe the public interest would be served by such a
limitation.
30. To a certain extent, these objections would be met by adop-
tion of some of the variations of this concept urged by others—
40 F.C.C.
674 Federal Communications Commission Reports
protection of existing facilities of some classes to a lower field
strength contour, and adoption of a reasonably significant minimum
for facilities, at least on some channels, However, none of these
would meet the last objection mentioned above—limitation of sta-
tions to their present facilities. Moreover, this “protected contour”
concept has the same disadvantage as does any plan other than a
Table of Assignments, in that it requires the making of assignments.
on the basis of present “demand,” without consideration of future
or other needs which have not yet been crystallized into application
‘orm,
31. It is also to be observed that the “protected contour” concept
would not even necessarily afford the “go-no go” certainty we believe
indispensable. For example—as has happened in the past—the filing
of an application seeking a new station, which would approach but
not quite cause interference within the 1 mv/m contour of an exist-
ing station, may lead to the filing by the existing station of an
application for increase in height or power, which if granted would
involve interference to or from the new proposal. Under these
circumstances obviously a hearing would be required, to determine
which application should be granted. It would appear that we would
then be in the same position we are now—contour locations would
have to be determined, populations counted, other services evaluated,
etc. Thus nothing would be gained.
32. For these reasons, we conclude that a plan based only on a
“protected contour” concept is not sufficient, and must be rejected.
erefore, we adopt, as the basis of assignments a table of mini-
mum co-channel and adjacent channel mileage separations, discussed
below, which we believe to afford the best basis for orderly, efficient,
and effective development of the FM broadcast service. This is based
on protection of stations of the various classes to a particular service
radius, using the curves and signal ratios mentioned above, and
assuming the maximum facilities for both existing and proposed
stations,
33. We do not conceive that this plan will involve the “waste,” or
crippling effect on the development of FM, that AFCCE and others
allege. That it may in some instances mean, for the moment, protec-
tion of non-existent “service” where stations operate with relatively
small facilities, is outweighed by the provision of opportunity for
expansion as the economic basis of the medium increases. Terrain
factors can be taken into account in such a plan, to the extent appro-
priate, as discussed below. It does not, as AFCCE argues, involve an
assumption as to distribution of population or cities (which could,
and as we propose will, be taken into account in a Table of Assign-
ments).
34. Leon argues that a mileage separation plan would be both
crippling on the one hand, as to “Zone I” (the Northeast), and un-
necessary on the other, as to “Zone YT” (the rest of the country). It is
asserted that under the wide spacings proposed in the Notice, only
about eight out of 49 applications pending as of last summer for
Zone I facilities could be granted—many fewer than under AFCCE’s
40 F.C.C.
FM Broadeast Rules 675
roposal. We do not conceive that use of the criteria adopted herei
Fall have anything like the restrictive effect asserted With. EE
this portion of the country. It should be borne in mind that the
spacings adopted herein are shorter than those proposed in the Notice
permitting some assignments which could not have been made under
our original proposal but can be made under the standards here
adopted, consistent with assignment efficiency and the public inter-
est. Analysis of the approximately 50 applications now pending for
new stations in Zone I (as of June 1962) indicates that a, number of
them can be granted under the standards now adopted, a number of
others can probably be granted substantially equal facilities on chan-
nels other than those requested, and a number could not be granted
anyhow, even under the AFCCE proposal, because they involve inter-
ference within the 1 mv/m contours of existing stations. It must be
borne in mind that in most of Zone I FM assignments are now ap-
proaching the saturation point, no matter what basis of assignments
js used, as shown by the fact that as of January 18, 1962 there were
approximately 580 commercial FM assignments in this area, com-
pared to a total of 644 provided in the Table of Assignments for-
merly used in the FM service, as amended up to February 12, 1952.
Analysis of the approximately 50 applications for new stations in
Zone II (as of June 1962) indicates that many of these can be granted
under our new standards, others can be accommodated on other chan-
nels, and some could not be granted even under the AFCCE’s pro-
posal, because of the interference which would be caused. With re-
spect to Zone I-A (Southern California), the situation with respect
to the ten pending applications appears to be about the same as Zone
L* In any event, whatever restrictions are entailed by the mileage
separation plan adopted here as compared to the AFCCE proposal,
in terms of applications which might be granted under it but cannot
meet the spacings adopted here, are outweighed by the overall effi-
ciency and preservation of service, and orderly opportunity for ex-
pansion, provided by our plan.
35. With respect to Zone II, AFCCE’s argument is that there the
demand for channels is and will remain substantially less, and there-
fore the assignment situation is self-correcting and no over-all plan
need be adopted. This we believe erroneous. In some parts of Zone IT,
such as the coastal Pacific Northwest and the area around Dallas-
Fort Worth, there is already a tight situation as to possible FM
assignments. Moreover, it may be expected that demand will increase
in the future, along with interest in FM and population and eco-
nomic growth. Clearly, if FM is to proceed to orderly development in
this portion of the country, now is the time for an over-all plan,
40 F.C.C.
676 Federal Communications Commission Reports
36. The Table of Assignments. In the July Notice (paragraph 23)
we discussed the idea of re-instituting a Table of FM assignments,
similar to that in effect from 1945 to 1958. This we rejected, for
essentially the same reasons the earlier Table was abandoned, that it
appeared to be an unnecessary and cumbersome step in the assign-
ment process. Those parties commenting on this matter appeared to
agree,
37. However, on further consideration, we have reached the tenta-
tive conclusion that the public interest will best be served by adoption
of such a table, just as in television, based on the mileage separations
adopted herein, for substantially the same reasons set forth in the
Sixth Report in 1952 (see the Sixth Report and Order in Dockets
8736, 8975, 8976, and 9175, released April 14, 1952, paragraphs 12 to
18). Briefly, these are: (1) a pre-engineered Table is the best way
to insure efficiency of channel use, better than leaving channel use
to the more or less random determination of application filing;7 (2)
a Table is the best way of making provision for future needs which
are not at the moment ripe for expression in application form—e.g.,
needs of smaller communities, and of areas where support for FM
is lacking at the present time; (3) a Table forms a better way of
insuring compliance with §307(b) of the Act — calling for fair and
equitable distribution of facilities — than does the random applica-
tion process, which necessarily has to a degree a “first come first
served” aspect.
38. The priorities and bases to be used in the Table are discussed
in the Further Notice simultaneously adopted. Comments thereon,
and upon the basic idea of a Table, are invited.
E Zones, Classes of Stations, Maximum and Minimum Facilities
ones
39. Presently, under §3.202 of the Rules, for the purpose of FM
allocations the country is divided into two Areas — Area 1, a portion
of the Northeast considerably smaller than present television Zone I,
and Area 2, the rest of the country. Our proposal in the Notice (para-
graph 85) was—under one alternative, “Plan II’—to expand Area 1
so as to make it roughly co-extensive with television Zone I, extending
as far west as the Mississippi. Actually, both at present and under
the proposed “Plan IT,” the “zone” concept has significance only with
respect to the facilities used by high power stations, the maximum
permitted being Jess in Area 1.
40, Some parties favored abolition of zones altogether, as being a
more or less arbitrary and discriminatory concept. It was asserted,
for example, that stations of considerably more power than the pres-
ent Area 1 maximum—20 kw E.R.P. and 500 ft. a.a.t., or equivalent—
can perform at least as valuable a function in the more populous
and crowded Northeast, where there is economic support for large
7 For example, in the Notice we raised the idea of mazimum, as well as minimum, sep-
arations, designed to insure efficiency of channel use. Further consideration leads us to
the view that this fairly complicated concept (which involves adjacent channel as well as
co-channel considerations) can best be applied as a general guide in working out a Table,
rather than used as a specific rule in dealing with individual applications.
40 F.C.C.
FM Broadcast Rules 677
ale operations and high quality programming, as they do in less
populous parts of the country. Other parties supported the zone con-
cept, for generally the same reasons mentioned in the Notice—that
pecause of the crowded assignment conditions and closely populated
character of the Northeast, there is both little opportunity for and
Jess need for great facility “Class C” stations rendering wide area
coverage; Whereas in the West, with its sparser population, more
widely separated cities, and fewer existing stations, there is both a
reat need for high power stations providing such coverage, and
opportunity for such assignments, As to the appropriate division of
the country into zones, most, parties commenting favored something
along the lines of our proposed “Plan II,” or something correspond-
ing to TV Zones I and IL
41, After due consideration, we conclude that the public interest
would best be served by division of the country into three zones, as
proposed by AFCCE and ABC. Our conclusion is based upon the
differences between the general areas of the country referred to above,
which make high powered stations, rendering wide area coverage, both
Jess needed and much less feasible in the Northeast than in the West,
where population is sparser and cities are often much further apart.
In view of the populous character of the Northeast, with its many
cities, it appears that stations operating with facilities in the general
order of the present Area 1 maximum should be able to have an
adequate basis of economic support. There appears to be no reason,
either from the standpoint of the character of the areas or of adm inis-
trative conveniences, why FM “Area 1” should not be co-extensive
with television Zone I. Therefore, as suggested by some of the parties,
we are redefining Area 1 to make it and TV Zone I the same.
42, It also appears that conditions in much of California either are
or may soon become the same as the Northeast in these respects.
Therefore, as AFCCE and ABC suggest, we are defining that por-
tion of California below the 40th parallel of latitude (which lies
north of San Francisco) as “Zone I-A.” Assignment rules here will
be the same as in Zone I, because of the similarity of conditions.
43. In reaching these conclusions, we have considered two other
suggestions as to what the appropriate zones should be. One is that
Zone I should include present Area 1 plus any U.S. Census standard
metropolitan statistical area, said to be a way of insuring that high
power, wide area stations would be assigned only in truly rural areas.
This we must reject, both because it would be unduly confusing and
subject to change with every Census, and because it would by no
means necessarily achieve a desirable result.
44. The other suggestion is based on propagation characteristics.
It is urged that we recognize, in FM as in VHF television, the
greater tropospheric propagation along the Gulf Coast, and take
similar account of the same phenomenon along the Southern Cali-
fornia coast south of Santa Maria. Recognizing the merit in both of
8 High power stations in standard metropolitan areas, especially in the South and West,
may well render a much needed service to wide rural areas having Uttle other service.
Moreover, it may be that support from such areas is desirable if high power operations of
good quality are to be provided.
40 F.0.0.
27902270 —45
678 Federal Communications Commission Reports
these positions from a strictly technical standpoint, we must none-
theless reject them. As to the Gulf Coast area of the South (television
Zone ITX), if adequate opportunity is to be afforded for the develop-
ment of FM—which, as an aura service, can be expected to support
more stations than television—a large number of assignments must be
made therein. These cannot be made if we impose minimum mileage
separations substantially larger than in the rest of the country, as in
television. The great facility “Class C” stations on 60 channels which
we provide for herein in Zone II will have, using the spacings se-
lected and the curves, protected service areas substantially larger than
their counterpart “Class B” stations in Zone T; and therefore, even
if in this area interference is more severe than that indicated by the
curves adopted herein, these stations will have adequate protection.
There does not appear to be in this area the need for extremely wide
area coverage which exists, for example, in the sparsely settled western
plains and intermountain areas, so the public will not suffer from the
closer spacings. It should also be borne in mind that, whether stations
are assigned on a separation basis or via a Table, only a very small
percentage of spacings will be at or near the minimum. Using special
spacings for a “Zone III” would also considerably complicate what-
ever assignment process is used, since, unlike television with its one
class of stations and only co-channel and first adjacent channel inter-
ference problems, FM has two classes of commercial stations and
interference considerations are present up to three channels removed.
A long series of separations would have to be worked out between
Class A and Class C stations on either side of the zone line, up to
three channels removed.
45. As to coastal Southern California, this area is already so
crowded that probably few additional assignments can be made 5, at
least as to other than low power Class A stations. Therefore the sepa-
ration used becomes of less importance, and, in order to make what-
ever assignments are possible, we must adhere to the Zone I spacings.
Classes of commercial stations
46. The FM Rules presently provide for two classes of stations on
commercial channels: (1) low power “Class A” stations, operating
with no more than 1 kw E.R.P. and 250 ft. antenna height above
average terrain, or equivalent. assigned in both Area 1 and Area 2
on Class A channels; and (2) higher power “Class B” stations on 60
Class B channels, operating in Area 1 with no more than 20 kw and
500 feet or equivalent (and in no event more than 20 kw), but with
no fixed maximum on facilities in Area 2.1° In the July Notice, we
proposed to retain these classes of stations but to add a third class—
larger “Class C” stations, designed to render wide area coverage
° For example, there are 20 Class E assignments within a radius of 40 miles of 8
Angeles. In addition, there are 15 Class A assignments in the same area. The San Dies
area has 13 Class B assignments.
30 Section 3.204(a) (2) provides that normally the maximum in Area 2 will be the same
as in Area 1, but greater height and power will be encouraged and considered, on an indi-
vidual basis, where undue interference would not result to existing stations or potential
assignments. The NAB pointed out that as of 1961, there were 261 Area 2 Class B sta-
tions authorized with power between 20 and 74.9 kw, and 63 with more than 75 kw.
40 F.C.C.
FM Broadcast Rules 679
where it is needed. We set forth two alternative proposals for assign-
ment of these stations: “Plan I,” under which 20 channels (con-
tiguous in the band) would be used for Class C assignments in both
‘Areas; and “Plan II,” under which Class C stations would be
assigned only in Area 2, on all of the present 60 Class B channels,
and no more Class B assignments would be made in that Area (Area
1 would continue to have Class B assignments). .
47. The concept of having three general classes of stations drew
support from many of the parties. AFCCE opposed it, urging simply
maintenance of the status quo in this respect, with no maximum in
Area 2. Two parties (Zenith and FM Unlimited) urged that there is
need for “Class C?” stations in both sections of the country, as pro-
osed in our “Plan I”; both urged provision of more than 20 chan-
nels therefor, Other parties favored “Plan II,” asserting that: (1) it
involves less sweeping changes from present practice; (2) in the
Northeast. (Area 1, as expanded) there is neither great need for nor
much opportunity for such higher facility stations; (3) there is need
for such assignments in the sparsely settled West, and this may
require more than 20 channels; (4) setting aside a band of channels,
such as 20, for use by high power stations, gives stations so assigned
an undue competitive advantage (in other words, all stations in the
same market should as far as possible be relatively equal in facilities.)
48. For the reasons last mentioned and discussed earlier in con-
nection with zones. we conclude that our “Plan IT” is more in the
public interest, and should be adopted. In Zone T. and Zone I-A (Cali-
fornia) where conditions are similar, Class A and Class B stations
will be assigned, on the channels now specified therefor. In Zone II,
which includes most of the country, Class A stations will be assigned
on the 20 channels now reserved therefor (see paragraph 25, above),
and on the remaining 60 channels Class C stations will be assigned.
There will be no new Class B assignments in this area. We have
given consideration also to reserving 20 channels for greater facility
Class C stations in Zone TI only, with Class B assignments on the
remaining 40 channels; but we conclude that this would not only be
difficult to do effectively (because of existing use of channels in some
parts of Zone II, but would lead to an undesirable situation because
of the factor of competitive inequality mentioned above. There will
always be differences in station facilities, where stations are assigned
for different purposes, as we recognized years ago in setting up
Classes A and B. But, where nothing much is to be gained, we do not
believe the public interest is served by building into our assignment
plan competitive superiority for a relatively few stations operating
on a limited number of channels. i
1 High Fidelity Broadcasters. Inc., a Maryland Class A FM broadcaster, proposed per-
haps the most radical reallocation of any party, including shifting Class A stations to
“interleaved” channels (already discussed), removing the reservation of any particular
channels for education, having Class B-1 and Class B-2 stations (the former, in Area 1,
the same as present Class B, the latter, In Area 2, operating with somewhat greater facil-
ities), and using the 20 percent Class A channels for high-power Class C stations in
Area 2 only. This must be rejected, not only because of its great complexity and the
problems connected with “interleaving,” mentioned above, but because of the factor of
competitive inequality just referred to.
40 F.C.C.
680 Federal Communications Commission Reports
Facilities for new commercial stations Séi
49. Minimum facilities. As to minimum facilities, the present rules
require provision of a 3 mv/m signal over the principal city
§3.311(c)), and otherwise provide only that the rated transmitter
power shall not be less than 250 watts for Class A stations and 1 kw
for Class B stations (§§3.203(a)) and 3.204(a)). As to Class B sta.
tions, at least, these minima are of no real significance from an over-
all assignment standpoint. Because of the pressure to “squeeze in”
stations, the result has been to clutter up many of these channels with
a number of small-scale facilities, making for inefficient channel use,
It was for this reason that in the Notice we proposed minima, in
terms of height and power (or equivalent), for the various classes of
stations: 100 watts and 100 ft. for Class A, 1 kw and 250 ft. for
Class B, and 20 kw and 500 ft. for Class C. s:
50. The commenting parties for the most part favored this idea
for new assignments (although some suggested it apply only to Class
B and Class C stations). Various minima were suggested,” including
absolute minima on antenna height above average terrain (as well ag
“equivalence”), and alternative minima where sufficient antenna
height might not be feasible. It was also suggested that the minima
for Class B and Class C should be higher than the maximum for the
next lower class, so there would be no “overlap” of station classifica-
tions.
51. As far as new commercial assignments are concerned, we adhere
to the view that certain minima should be imposed, but only as to
power. In some instances, a station may have a reasonably favorable
antenna location with respect to its principal community, and at the
same time have a negative antenna height with respect to the average
of all eight radials. In this situation it would be unduly burdensome
to require increase in power to meet an “equivalence” standard. Ade-
quate safeguards in this respect are provided by our present rules
(herein reaffirmed), requiring a signal of at least 3 mv/m over all of
the principal community, and where possible location so as to have
line of sight over that community. (Sections 3.311 and 3.315). The
rule we adopt herein is that—except where antenna height is so great
that use of the specified power would exceed the maaimum equiva-
lence standard (in which case that standard will govern)'*—new
stations must operate with no less than the following effective radi-
Di e specifie proposals were: Earl Cullum, none for Class A, 10 kw and 250 ft. (or
equi t) for Class B or C, gh Fidelity Broadcasters, Inec., Class A, 500 watts and
100 ft. or 100 watts and 250 ft.; Class “B-1” (B's in Area 1), 1.2 kw and 500 ft. or 12
kw and 150 ft.; “B-2” (B's in Area 2) 8 kw and 500 ft. or 60 kw and 200 ft.; Class G,
300 kw and 600 ft. or 100 kw and 1,000 ft. FM Unlimited: Class A, 1 kw and 250 ft. min-
imum h ht of 75 ft. ; Class B, 20 kw and 500 ft. minimum height nat of 250 ft;
Class C. 200 kw and 1.000 ft.. with minimum height a.a.t. of 1,000 ft.
The minima proposed by High Fidelity are designed to insure that Class A and B sta-
tions render urban service at least 50% as far as, and Class C stations at least 85% as
far as. they would if operating with maximum facilities—a standard in general consider-
ably higher than that provided by the requirements we adopt herein. But, desirable as
this may be from an over-all efficiency standpoint, we believe such high minima would
tend to restrict the development of the service.
18 These exceptional situations will probably occur mostly in Zone I, where, under the
standards adopted below, Class B stations will have maximum facilities of 50 kw and 500
ft. a.a.t., or equivalent. Where antenna height exceeds about 1,250 feet (as it does, for
example, with the New York City stations located on the Empire State Building) such
stations could not be permitted, much less required, to operate with as much as 5 kw.
40 F.C.C.
FM Broadcast Rules 681
ated powers: Class A, 100 watts; Class B, 5 kw; and Class C, 10 kw.
These minima are lower than those proposed in the Notice and most
of those proposed by the parties; but in our view they are enough to
safeguard over-all efficiency and at the same time they are low enough
to permit reasonably economical operation and thus encourage the
development of the service. Since there will not be Class B and Class
C stations in the same area, and since Class A stations operate on
separate channels, there is no need for concern about the “overlap-
ping” of facilities of the different classes.
Maximum facilities for commercial stations
52. Class A. The July Notice proposed to retain the present maxi-
mum on the facilities of low power Class A stations—1 kw and 250
feet above average terrain, or equivalent. No commenting party urged
a lower figure; some supported this and others urged higher figures,
such as 2.5 kw and 250 feet, 5 kw, or even 10 kw and 250 feet. It was
urged that more power is necessary especially in the case of Class A
stations located in metropolitan areas near large cities, to overcome
man made noise, built-up area conditions, etc., as well as in order to
compete with the numerous more powerful Class B stations in the
city. We believe there is merit in this argument. Further staff studies
have shown that an increase in the maximum facilities of stations on
this class can be provided, and at the same time an adequate number
of assignments on these channels can be provided for. A maximum of
3 kw and 300 feet above average terrain (or equivalent) appears to be
appropriate, and is adopted herein. These facilities, which under the
mileage separations adopted below would give a service radius of 15
miles, appear to be great enough to meet the problems resulting from
the present restriction, and at the same time not large enough to
create serious over-all assignment problems,
53. Class B. The July Notice proposed to retain for Class B sta-
tions the present Area 1 maximum, 20 kw and 500 feet above average
terrain, or equivalent, Some parties supported this figure (as far as
Area 1 is concerned, which under our decision herein is the only area
where Class B stations would be assigned). Others urged an increase,
some going as far as 20 kw or even 100 kw at 1,000 feet. These pro-
posals must be rejected, because. as already mentioned, there is neither
great need nor much opportunity for making such high power assign-
ments in Zone I, and if made they would preclude other needed
assignments. Of more merit are suggestions made by two parties
(CBS and WQR) concerning the need for some increase, particu-
larly in order to afford adequate coverage of metropolitan areas which
are expanding rapidly with suburban development. It is pointed out,
for example, that from the center of lower Manhattan, (where a num-
ber of New York City FM stations are located), it is 23 miles to the
furthest point of that city, and the distance to the outer edge of most
of the New York-northern New Jersey urbanized area is from 35 to
40 miles. Similar situations prevail in some other cities. Therefore,
it is urged, an increase in maximum facilities to 50 kw and 500 feet
(or equivalent) should be permitted. in order to permit provision of
40 F.C.C,
682 Federal Communications Commission Reports
a 3 mv/m signal to a distance of 24 miles and a 1 mv/m signal to a
distance of 33 miles. We agree with these views, and accordingly are
herein amending our rules to provide that the maximum facilities for
stations herein classified as Class B (De, those stations in Zone I and
I-A operating on Class B-C channels) shall be 50 kw E.R.P. and 500
feet above average terrain, or equivalent.
54. Class C. As to Class C stations—which under our decision
herein will be assigned only in Zone [l—these stations, often serving
sparsely settled areas where there are relatively few sizeable com.
munities, are expected to render wide area coverage, and therefore
must be permitted to operate with great height and power where pos-
sible. In the Notice, we proposed a maximum of 100 kw and 2,000 feet
above average terrain, or equivalent. The commenting parties who
suggested specific figures either supported this or proposed other
maxima which are generally comparable (e.g., 200 or 300 kw and
1,000 feet). In this respect, therefore, we afirm the proposal in the
Notice, and for Class C stations (ie., stations in Zone IT operating on
commercial channels other than Class A) the maximum facilities per.
mitted will be 100 kw and 2,000 feet above average terrain, or
equivalent. à
55. AFCCE and other parties argued that there should be, as now,
no nbsolute maximum on facilities Im Zone II, where (it is asserted)
there is and will be less need for assignments that any problems tend
to be self-correcting. This contention must be rejected. Not only is
the absence of such a restriction completely inconsistent with a mile-
age separation table and a table of assignments, but, even in the
absence of such assignment plans, it permits grants of great height
and power which may preclude future needed assignments. In short,
it is wasteful, inconsistent with any rational over-all approach, and
not in the public interest. All other services are subject to such restric-
tions, and FM Zone TI should be also.
56. Use of E.R.P. greater than the “maximum” specified (where
antenna height is low) is discussed below in connection with “equiva-
lence”, For reasons stated, we must reject this concept.
VI. Signals, Protected Areas, and Separations
Signals for service
57. The present FM standards (§3.311(b) of the Rules) provide
that in general a signal of 50 uv/m is sufficient for service to rural
areas, and a signal of 1 mv/m is required for service to city, factory
and business areas, with 8 mv/m required over the station’s principal
city. In the July Notice we asked for comments about these values,
and we specifically proposed to retain the 3 mv/m value as a basis for
principal city coverage.
58. From the comments received, which were for the most part
general in nature, we see no reason to change these concepts, and they
are reaffirmed. Most of the parties commenting favored the 3 mv/m
figure for principal city service as appropriate. One party suggested
that the corresponding low band television VHF value, 74 dbu (5
40 F.C.
FM Broadcast Rules 683
mv/m) be used instead; but no data in support of this suggestion
as advanced and the suggestion is rejected. For convenience, we
adopt the standard of 70 dbu, which corresponds to 3.16 mv/m.
Protected areas . f
59. In the Notice, the concept of station protection was put in
terms of a particular service area radius, within which the station
would be protected against objectionable co-channel and first adjacent
channel interference. This was to be large enough to permit the sta-
tion to obtain an adequate basis of economic support and fulfill its
particular function (coverage of a city and suburbs, wide area rural
coverage, or coverage of a smaller town and environs), and at the
same time small enough to permit other co-channel and adjacent
channel stations to be spaced sufficiently close so that an adequate
number of assignments might be made. The protected radii proposed
were: Class A stations, 25 miles; Class B stations, 50 miles; and
Class C stations, 100 miles. With the maximum facilities proposed in
the Notice, this amounted to protection to the 140 uv/m (43 dbu)
contour for Class A stations, to the 178 uv/m (45 dbu) contour for
Class B stations, and to the 84 uv/m (38.5 dbu} contour for Class ©
stations. The co-channel spacings necessary to protect these radii are,
respectively, 115, 190. and 300 miles. With respect to second and third
adjacent channel interference, we took cognizance of the. fact that
(because of the negative ratios involved) the area of such interfer-
ence is small and within it the service lost is completely replaced by
the service of the interfering station. Therefore, we proposed that the
service radius protected against such interference would be less—10
miles for Class A, 25 miles for Class B, and 35 miles for Class C.
60. As to co-channel and first adjacent channel spacings, some
parties (including the N.A.B. and CBS) supported those proposed in
the Notice and urged that they not be shortened. However, more par-
ties opposed them as too long. It was asserted that the proposed sepa-
rations would prevent the making of many needed assignments; 14
that they would mean protection of “service” which in fact does not
exist because the average FM receiver is not an expensive one and
does not work well for stations over 15 miles away; that the proposed
` spacings ignore the fact that listeners im “in-between” rural areas,
when they have better receivers, often also have directional, rotating
receiving antennas which can distinguish between stations; that lis-
teners in these “in-between” areas will suffer because future assign-
ments would have to be too far apart to be received even with a direc-
tional antenna; and that, even if the “service” protected is technically
usable, the programming of a distant station is probably of little
significance to, or used by, listeners. Little specific data in support of
these contentions was advanced.
61. Some of the parties offered specific proposals in this area. Earl
Cullum proposed that, between co-channel high power stations, the
14 For example, one party asserted that under the proposed spacings it would be impos-
sible to provide a Class B assignment in Salisbury, Maryland, needed for wide area cov-
erage in this rural region because of the single existing assignment to the Delmarva Pen-
insula south of Wilmington.
40 Y..C.C.
684 Federal Communications Commission Reports
same spacings be used as in television—170 and 190 miles in
and Zone II, respectively, and, between co-channel low oe ere
tions, spacings of 85 miles in Zone I and 95 miles in Zone II. This
would give the high power stations protection to their 57 dbu (ap-
proximately 700 uv/m) contours, a distance of 53 miles in Zone I and
69 miles in Zone II. The low power stations would be protected to
their 1 mv/m contours in Zone I, a distance of 18 miles, and to their
57 dbu contours, a distance of 21 miles, in Zone TI. Corresponding
first adjacent channel spacings would be 125 and 160 miles between
high power stations in Zones I and II, respectively, and 45 and 55
miles between low power stations in the respective zones. High Fidel-
ity Broadcasters, Inc., proposed an elaborate set of spacings designed
to protect the 0.5 mv/m contour of all stations except Class C sta-
tions, which would be protected to their 0.1 mv/m contours. In terms
of protected distances, this would mean 15 miles for Class A, 40 or 50
miles for Class B (depending on the zone) and 90 miles for Class C.
Another party proposed (without reference to zones) considerably
shorter spacings, based on the reasoning referred to in the previous
paragraph: 95 miles co-channel and 80 miles adjacent channel be-
tween Class B’s, and 60 miles co-channel and 45 miles adjacent chan-
nel between Class A’s. Other suggestions, made by parties proposing
only a “protected contour” concept, were for protection to the 1
mv/m contour (AFCCE), or to the 1 mv/m, 0.5 mv/m, and 0.1
mv/m for Class A, B, and C stations respectively (FM Unlimited),
62. Further consideration of this matter, and our staff’s studies
have indicated that using the spacings set forth in the Notice, or even
spacings as great as those proposed by Earl Cullum, it is simply not
ossible to make the number of assignments which must be provided
if the FM service is to be of optimum value, A compromise was found
to be necessary. It was found that a reasonable compromise, afford-
ing reasonably adequate protection on the one hand and yet permit-
ting a sufficient number of assignments, is to provide protected serv-
ice radii for the various classes of stations as follows: Class A, 15
miles; Class B, 40 miles; and Class C, 65 miles. Protection of these
radii requires co-channel s acings as follows: between Class, A sta-
tions, 65 miles; between Class B stations, 150 miles; and between
Class G stations, 180 miles. Assuming that the station is operating
with maximum facilities provided for above, the spacings selected
amount to protection to the following field strength contours: Class
A, 927 uv/m; Class B, 562 uv/m; Class C, 944 uv/m. First adjacent
channel spacings necessary to afford the same degree of protection
are: between B and B, 105 miles; between C and C, 150 miles; be-
tween A and B, 65 miles; and between A and C, 105 miles. These
minimum mileage separations, together with others necessitated by
the plan adopted herein for educational assignments, are set forth in
the Table which appears following the discussion of educational
assignments, These separations will be used as the basis of our pro-
posed Table of Assignments.
35 Mileage separations have in all cases been rounded out to the nearest five-mile figure,
whether higher or lower than the exact value determined from the curves and ratios.
40 F.0.0.
FM Broadcast Rules 685
63. It is recognized that the spacings, protected radii and pro-
tected contours just mentioned are cons derably Jess than those SS
posed in the Notice and by some of the parties. This is particularly
true with respect to wide area Class C stations, for which we orig-
inally proposed protection out to a distance of 100 miles, the 84 uv/m
(88 dbu) contour if maximum facilities are used, with co-channel
spacing of 300 miles, Such wide separations turned out to be incom-
patible with making an adequate number of Class C assignments. It
must be borne in mind that, in any Table of Assignments, few spac-
ings will actually be at or very close to the minimum, so that on the
average, and in the majority of cases, the degree of protection af-
forded will be higher. This may be expected to be true, for example,
in most of the sparsely populated plains and mountain West, where
there are not enough sizeable communities to require a large number
of closely spaced Class C assignments, and where, therefore a sub-
stantially greater degree of protection to each Class C station can be
afforded. Concomitantly, this of course is the area where wide area
coverage is particularly valuable, because of the distance between
communities, In this respect, the situation is, as the AFCCE pointed
out, self-correcting.+¢ In sum, we conclude the separations mentioned
to be those most appropriate for the optimum development of the
FM service.
64, As to second and third adjacent channel interference, our pro-
posal to have a smaller radius protected against such interference
(on the basis of the “substitution of service” concept) drew some sup-
port but more opposition. Tt was asserted, for example, that one sta-
tion does not necessarily equal another, even as between two commer-
cial stations, and that this is true z fortiori where one of the stations
is non-commercial educational (a situation which could arise between
an educational station on Channel 218, 219 or 220, and a commercial
station on Channel 221, 222, or 223). One suggested compromise was
that a new station two or three channels removed should not be re-
quired to afford the existing station absolute protection to the same
protected contour as would a new co-channel station, but at least it
should have to be located outside of that contour (eg., under the
AFCCE’s proposal, a new station two or three channels removed
would have to be located outside of the existing station’s 1 mv/m
contour).
65. After consideration, we conclude that the last-mentioned sug-
gestion is appropriate for adoption. We agree that our earlier concept
of a substantially smaller protected service radius against second and
third adjacent channel interference is perhaps extreme, and a greater
degree of protection should be afforded. On the other hand, there
must be taken into account (1) the need for making numerous assign-
ments; (2) the fact that these interference situations do represent a
complete substitution of service technically and at least to some de-
18 Conditions in the various parts of Zone II are somewhat different, in that the Mid-
west and South are more populous, with more closely spaced communities. At one point
in the staff’s study, consideration was given to creation of additional “zones” to take this
difference into account. However, it appeared that this would substantially complicate the
assignment process, and that whatever differences exist can be accommodated because of
the factors set forth in the text.
40 F.C.C.
686 Federal Communications Commission Reports
gree as a matter of listening reality; (3) the fact that the areas of
interference involved—occurring immediately around the transmitter
of the interfering station—are relatively small; (4) the fact that at
least some receivers are capable of dealing with 400 or 600 ke inter.
ference; *” and the fact that, under this concept, the existing station
would be protected, if not completely to the same service radius as
against co-channel interference, at least for a very substantial dis-
tance. Therefore, the separations adopted here (which will form the
basis of our proposed Table of Assignments) will provide that sta-
tions on second and third adjacent channels to existing stations must
be located further therefrom than the “protected” distances specified
above—15 miles where the existing station is Class A, 40 miles where
it is Class B, and 65 miles where it is Class C.
_ 66. In adopting the separations specified, we have in large part re-
jected the contentions mentioned above, that FM receivers are for the
most part inexpensive and not really of good quality, and that we
should take this into account by providing extremely short separa-
tions, No data was advanced in support of this, and other parties as.
serted that receivers are steadily improving. In any event, we must
agree with the point made by AFCCE and Zenith, that an assign-
ment plan should be based on receivers of reasonably good quality,
To sacrifice other important values, simply in order to base a plan on
the cheapest and least satisfactory receivers in common use, would
not serve the public interest. It would tend to remove any incentive
for the development and purchase of better receivers.
VII. The Educational Channels
67. In the July Notice (paragraph 30) we did not propose any
basic changes in the present allocation of the lowest 20 channels of
the FM band (except in Alaska) for noncommercial educational use,
68. The comments upon the educational aspect of FM were of two
general types. One group of comments proposed abolishing the edu-
cational reservation, or modifying it. Earl Cullum suggested that it
be abolished, with, if necessary, provision of specific channel reserva-
tions by way of a Table of Educational Assignments. Zenith sug-
gested eliminating the 20-channel reservation, with all 100 channels
to be divided into three bands according to the height and power of
stations operating therein, and in each band certain channels reserved
for education. FM Unlimited urged (as part of an over-all reshuflling
of existing stations) that the educational band be opened to non-
educational but “non-commercial” facilities, such as municipal and
religious stations.’ Intercollegiate Broadcasting System, an organi-
zation of “campus” stations, urged that educational stations, or at
least the low power 10 watt ones, be permitted to operate on a com-
17 One party urged, as reason for low protection against 2nd and 3rd channel interfer-
ence, the idea that two elements of receiver quality, sensitivity and selectivity, go hand
in hand, so that a receiver capable of getting a station at some distance can also deal
with such interference. This may or may not be generally true (no supporting data was
Zeen). To the extent it is, it supports the concept adopted here. S
ag FM Unlimited's proposal, which also involves some actual deletion of existing sta-
tions, is part of a plan to free much of the FM band for a wholesale reshufiling of
stations.
40 FCO
FM Broadcast Rules 687
mercial but “non-profit” basis, so as to enable colleges to recoup the
cost of operating the station and provide a means of training stu-
dents in commercial, as well as non-commercial, broadcast operations,
69. While there is merit in some of these suggestions, we are of
the view that none of them should be adopted. Zenith’s proposal
while perhaps of some merit as an initial plan, is too complex for
adoption at this point. As to Cullum’s suggestion, it is apparent that
a band of 20 channels is necessary for accommodation of the present
and future needs of the educational FM service. For reasons dis-
cussed below (paragraph 70) a Table of Assignments in this service
appears desirable. The FM Unlimited proposal would involve an
unwarranted encroachment upon the educational band. It may be
as asserted, that the service of other kinds of “non-commercial” sta-
tions (¢.g-, WNYC-FM, the New York City municipal station) bears
some similarity to the service rendered by some educational stations;
but this is not completely true, and, as mentioned, the 20-channel
band appears none too large for the needs of educational institutions
and groups per se. For example, in the New York City-Newark area
there are already five educational assignments, the maximum which
can be made in 20 channels. The last suggestion, concerning “non-
profit” but commercial operation, in our view must be rejected. This
would involve an undue and inappropriate dilution of the concept
of non-commercial educational broadcasting, would probably result
—as far as the listener is concerned—in simply turning so much of
this band over to regular commercial operations, and might. involve
accounting problems as to what is or is not “non-profit”. In our
judgment, operations in this band must remain not only non-profit
but non-commercial.
70. The second group of comments, from educational groups, re-
lated to the manner of use of the 20 reserved channels. The chief
point urged by these parties, including the National Association of
Educational Broadcasters (NAEB), the University of Michigan
(WUOM), and the National Educational Television and Radio Cen-
ter (NET), was the need for flexibility in this service. It was pointed
out that educational stations are located less with respect to centers
of population than are commercial stations, and there is often need
for a particular location so as to implement a state-wide or area-wide
educational network. Therefore, it was asserted, there should be no
Table of Assignments in this service, there should be no minimum
separations but applications should be handled on the basis of inter-
ference considerations only—the same basis proposed by the AFCCE
for commercial assignments, protection of the 1 mv/m contour—and
there should be no maximum on facilities, other than for the 10 watt
stations. WUOM pointed out that in its case relatively great facilities
used at Ann Arbor enabled it to serve the Detroit area much better
than it could otherwise do. As to minimum facilities, some of these
parties urged none, and another urged a minimum of 100 watts and
100 feet above average terrain for other than the 10 watt stations.
71. We recognize that there is merit in some of these suggestions,
and therefore we do not propose to adopt a Table of Assignments in
40 F.C.C.
688 Federal Communications Commission Reports
the educational service. This does not mean, however, that some re-
strictions may not be necessary in order to insure the most efficient
and optimum development of the service. However—except for the
highest three educational channels which are adjacent to commercial
channels, discussed in the next paragraph—we do not adopt at this
time any restrictions as to maximum facilities or minimum separa-
tions. A Further Notice will be issued shortly in this proceeding, pro-
posing whatever general educational FM assignment rule changes
appear to be most in the public interest.
72, As to the three channels at the top of the educational band,
Channels 218, 219 and 220, other considerations apply. These are
within 600 ke of commercial Channels 221, 222 and 223, and author-
izing educational stations thereon without regard to mileage separa-
tion and with no limit on facilities would mean problems in making
commercial assignments on these channels, which is already difficult
in some areas. Therefore, as to these channels, we must apply the
same standards adopted for commercial stations, insofar as adjacen-
cies to the commercial channels are concerned. For this purpose, edu-
cational stations on Channels 218, 219 and 220 will be classified as
follows: (1) stations operating with no more than 10 watts rated
transmitted power will be classified as “Class D” stations; and (2)
all other stations on these channels will be classified just as would
commercial stations of the same height and power at the same loca-
tion—ie., if authorized with no more than 3 kw E.R.P. and no more
coverage than the equivalent of 3 kw and 300 feet antenna height
aat., they will be classified as Class A stations; and if authorized
with greater power or coverage they will be clasified as Class B sta-
tions if in Zones I or I-A, or as Class C stations if in Zone II. New
educational stations on Channels 218, 219 and 220 must meet the ap-
plicable minimum mileage separations with respect. to existing com-
mercial stations on Channels 221, 222 and 223, just as would a com-
mercial station of the same class at the same location. In the case of
Class D stations, these separations are based on assumptions of 10
watts E.R.P. and 100 feet effective antenna height. New Commercial
assignments on Channels 221, 222 and 223 will of course have to meet
the same spacings with respect to existing adjacent channel educa-
tional stations on Channels 218 to 220. Class D stations on Channels
218, 219 and 220 will be limited to 10 watts transmitter power; all
otier new stations thereon will be limited to the maximum specified
for Class B or Class C commercial stations, depending on the zone in
ich they are located. 2 I
EC The above criteria will govern the grant of educational appli-
cations for Channels 218, 219 and 220, and applications not meeting
these criteria will not hereafter be accepted for filing. With respect
to the educational band in general, our interim processing procedure
adopted in December 1961 did not impose any restrictions on applica-
tions for these frequencies. Pending further consideration of the ap-
propriate basis for making assignments on these channels, we will
continue the same procedure, except that: (1) applications for the
three top channels, 218, 219 and 220, will be subject to the facilities
40 F.C.C.
FM Broadcast Rules 689
limitations and separations with respect to adjacent channel commer-
cial stations just mentioned; and (2) no application will be granted
where it would cause interference within the 1 mv/m contour of
another station on the reserved channels, as determined on the basi
of the F (50, 50) and F (50, 10) curves used under the interim pro-
cedure. Section 1.356 of the Rules is amended accordingly.
74. The discussion herein is of course confined to use of the 20
channels reserved for educational use. Noncommercial educational
stations may, as they have in the past, apply for operation on the $0
unreserved channels, in which case they will be subject to the rules
applicable to stations on these channels,
FHI. The Table of Minimum Mileage Separations
75. Set forth below is the Table of Minimum Mileage Separations
between stations up to 600 ke removed. In every case, the reciprocal
separation, not shown, is the same (eg., C to A is the same as A to
C). Some separations—B to C, and vice versa—are set forth for use
in computations involving stations on either side of zone lines (a
Class B in Zone I or I-A, and a Class C in Zone IT).
Minimum separations (miles) Class of station and frequency separation (kes)
Class A Class C 10-watt educational
Co- 209 400 200 400 600 Co- 200 400 600
Ch. Ch.
40 15 J05 65 Lä 15
Se ee 135 65 4 40
Zege 150 65
IX. Equivalence; Terrain Factors
76. Our present rules (883.203 and 3.204) provide that, where sta-
tions operate with antenna height above average terrain greater than
the “maximum” provided for their class and zone, they shall reduce
power so that their 1 mv/m contours extend no further than they
would if operating with the “maximum” antenna height and maxi-
mum E.R.P. In the Notice (paragraph 58) we pointed out that great-
er height increases service more than it does interference, and there-
fore—since interference is the limiting factor in station assignments—
it might well be that the test for “equivalence,” or permissible power
with great antenna height, should be based on the co-channel inter-
ference contour (0.1 mv/m) instead of the 1 mv/m “service” contour.
77. A number of commenting parties supported this proposal.
However, one, Earl Cullum, pointed out that, while use of the 0.1
mv/m contour would provide adequate co-channel protection, it would
not do so in the case of adjacent channel operations. Our stafi’s analy-
sis confirm this. For example, assume a Class B station operating
with 50 kw E.R.P. and 500 feet above average terrain and a first
adjacent channel Class A station at a spacing of 70 miles operating
40 F.C.c.
690 Federal Communications Commission Reports
with 3 kw and 300 feet. If the Class B station increases antenna
height to 2,000 feet, using its 1 mv/m contour as the criterion it would
be limited to 1.6 kw (2 dbk} power, and would protect the Class A
station to about 16 miles. On the other hand, if the Class B’s new 0.1
mv/m contour is to be the basis, that station could radiate 20 kw
(18 dbk) power, and would protect the Class A station only to about
10 miles. Further study shows that no other contour would be sub-
stantially better. Therefore, the rules adopted herein provide that, as
heretofore, equivalence (the E.R.P. permissible when antenna height
is greater than that specified as the maximum standard) will be deter-
mined by the distance to the 1 mv/m contour.
78, In connection with equivalence, commenting parties raised two
points which merit discussion. Under the present rules, as to Class A
stations everywhere, Class B stations in Area 1, and “normally” as
to Class B stations in Area 2, the E.R.P. specified as part of the
“maximum” facilities is also an absolute maximum regardless of an-
tenna height (e.g., in Area 1, the “maximum” height and power are
20 kw and 500 feet; 20 kw is also the maximum E.R.P. which may
be employed regardiess of height). It was urged by some parties that
where antenna height is less than the “maximum,” more power than
the “maximum” be permitted. Zenith and one other party proposed
increase in power at lower antenna heights without restriction as long
as the “equivalence” maximum is not exceeded. FM Unlimited pro-
posed fixed but relatively high maximum powers under these condi-
tions (5 kw for Class A, 100 kw for Class B, and 500 kw for Class C).
79. Superficially, this idea has some plausibility; but on analysis
we conclude that it should not be adopted. First, comparing a given
increase in height with a given increase in E.R.P., an increase in
height. increases service more than it does interference, whereas an
increase in power increases interference more than it does service.
Therefore, we should obviously encourage improvement in service
through greater height rather than greater power, and affording an
opportunity for power increase, without limit or at least to a greater
extent, would work in the other direction. Second, it must be borne
in mind that the propagation curves adopted herein, while they are
reasonably satisfactory and appear to be the best available, are not
an exact tool. They are merely a prediction on a statistical basis of
what will occur. Actual interference may exist, to particular listeners
at particular locations, even where under the curves as adopted there
would be no “objectionable interference” within the ratios and other
provisions of the rules. Since this is so, and bearing in mind the close
relationship which the amount of E.R.P. has to interference, we can-
not permit an increase in power so as to reach the “equivalence” stand-
ard. on the basis of these curves.
80. The second general concept advanced by some of the parties is
that the “equivalence” concept should be based not on height above
the average of terrain along all eight radials, as it is now, but should
be based on height above terrain in particular directions. Karl Cullum
suggests that it should be based on the greatest antenna height above
average terrain (2 to 10 miles) along any radial and that “cutting
40 F.C.
FM Broadcast Rules 691
back” in power should be required only in those directions where the
height above terrain exceeds the “maximum”, this to be done by direc-
tional antennas. Another party also took note of antenna locations on
the side of a mountain range overlooking the principal city, and sug-
gested that the critical radial should be that over the city.
81. These concepts have not been used hitherto either in FM or tele-
vision, and we conclude that they should not be adopted now. Both
approaches present substantial practical problems. In the case of the
Cullum suggestion, in order to have any significance at all the show-
ing would presumably have to include not only height along each of
the eight radials now used, but, since these in themselves do not
necessarily represent the lowest terrain, the application would have to
show the terrain in many directions—a very difficult thing to prepare
and evaluate. The proposal concerning the radial over the principal
city overlooks the fact that this particular radial may not be the cru-
cial one as far as interference to existing stations is concerned. Since
the present approach has proved at least reasonably satisfactory, we
have concluded to retain it. As to Cullum’s suggestion that “cut-
back” be required only in directions where antenna height is greater
than the “maximum”, this would involve the same complications
mentioned above.
Terrain factors
82. A number of commenting parties urged—sometimes in opposi-
tion to the idea of a Table of Separations, sometimes in connection
with equivalence, as discussed above, and sometimes in general—that
in any assignment plan we should retain some degree of flexibility to
take into account terrain factors, e.g., the fact that an intervening
mountain range between two co-channel stations will both limit the
service of each and prevent the signal of the other from being as
much of an interference factor as it might otherwise be.
83, As mentioned above, it would be possible to take such factors
into account in a mileage separation or table of assignment plan.
However, after considering this matter we are of the view that they
shoud not be taken into account, for the present, to any extent beyond
what they now are, in the calculation of over-all height above aver-
age terrain on the basis of the height from 2 to 10 miles along each
of eight radials. There is at this time not sufficient data to determine
with any degree of precision the effect of intervening terrain upon
either desired or undesired signals. It may be true as a general propo-
sition that an intervening mountain range will cut down propaga-
tion; but this is not true in all situations. There are gaps in such
ranges through which signals may travel; there are reflected signals;
and it is even possible, if the geometry of the intervening barrier is
favorable, to obtain an obstacle gain over it. Moreover, there is no
reasonably simple way by which such factors can be taken into account,
in connection with the type of plan adopted here or any other (such
as “protected contours”). Measurements we have already concluded
19 Even in the relatively few cases where computation on the basis of an individual
radial would make a substantial difference. the difference would not amount to more than
a few miles in the limit to co-channel or adjacent channel stations.
40 F.C.0.
692 Federal Communications Commission Reports
to be out of the question. Occasionally, in television, the showing of
more radials, or of longer radials (eg, 2 to 30 miles) has been sug-
gested, but these ideas have never been accepted because it did not
appear that enough would be gained to justify the substantial addi-
tional effort involved on all sides. The same appears to be true in the
present case. Therefore, the minimum spacings, and heights, powers,
and equivalence standards, adopted herein will apply to all types of
terrain until such future time as sufficient information is available
which will enable us to predict with some precision the effect of ter-
rain on signal strengths.”
X. Directional Antennas and Polarization
Directional antennas
84. In the Notice herein (paragraph 65(b)), we asked for com-
ments concerning use of directional operations in the FM service—
what requirements should be adopted, what degree of suppression is
feasible, for what purpose should they be permitted (e.g., whether
the should be used as an assignment tool), and what form of assign-
ment plan can be adopted to take such installations into account.
85. With respect to the major question involved—the relationship
of such installations to station assignment principles—there was
sharp division of opinion in the comments. Some parties, such as
AFCCE, would employ DA’s wherever possible in order to protect
existing contours and “squeeze in” assignments. Earl Cullum would
use them, where appropriate on a case-to-case basis, to provide low
power assignments rendering needed service and protecting high
power stations, Other parties (generally those favoring our proposal
of mileage separations, such as the NAB) urged that they be per-
mitted where useful in order to avoid wasting service over water,
improving service toward cities, etc., but not as an assignment tool—
Le., not for suppressing radiation in 8 particular direction so as to
reduce the required spacing between stations.
` 86. We are of the view that directional antennas should be per-
mitted, and even encouraged, in the FM service, but only for the pur-
pose of improving service in the ways mentioned, and not as an
assignment tool. Therefore, it is our view that they should not be used
as a device for reducing the co-channel and adjacent channel spacings
mentioned above. Not only would such a use obviously be incompati-
ble with the preparations of a table of the assignments, but it would
tend to thwart the orderly and efficient development of the medium
generally. In our view, directional antennas must be used only on the
basis they do not radiate, in any horizontal or zenith direction, more
than the maximum power permissible for an omnidirectional opera-
% One of the parties making this terrain argument (KING) mentions certain particular
inter-city separations as being appropriate for this type of treatment—Seattle-Spokane,
San Francisco-Reno, and Salt Lake City and Grand Junction to Denver, Colorado Springs
and Pueblo. In all cases, the spacings we adopt herein would permit co-channel assign-
ments in these cases. dë . í
The matter is also of less significance when it is realized, as one party pointed out,
that be and large the areas of the West where this could be a real consideration are
those of relatively little need for close assignments, since there ar fewer communities.
40 F.C.C.
FM Broadcast Rules 693
tion; and stations will not be assigned at substandard spacings sim-
ply because, by directionalizing, they “protect” existing stations.
97. Our proposed rules concerning directional antennas are set
forth in the Further Notice. Comments thereon are invited. Mean-
while, we are amending the rule concerning the showing required of
applicants specifying DA’s, to make it conform to the TV rule
$3.65 ( f)), requiring a showing in both horizontal and vertical
planes (see Appendix B, new §3.316(c)). Pending adoption of rules
in this area, no application will be accepted where the maximum-to-
minimum ratio is more than 15 db.
gg. As to the extent of suppression which is feasible, commenting
parties favored from 15 db to 20 db maximum-to-minimum ratio.
One party suggested 50 to one (power), which is 17 db. Our proposal
jn this respect, set forth in the Further Notice, is for 15 db, which
appears feasible and safe.
Polarization
89. Our present Rules (§3.316) presently provide that horizontal
polarization shall be standard, but they also provide for elliptical or
circular polarization, with the supplemental vertical component in
such cases not to exceed the horizontal E.R.P. of the station. In other
words—-a point apparently not fully wnderstood-—-FM stations can
now use as much vertical polarization as horizontal, up to hte E.R.P.
specified in their authorizations. If a station as a Class B station in
Area 1 may now radiate a maximum of 20 kw E.R.P., it may radiate
90 kw in both the horizontal and vertical planes if it receives author-
ity for such operation. Thus, any station wishing to provide a vertical
component to improve reception by auto whip antennas may do so.
Some of the parties urged us to encourage vertical or circular polari-
zation. Others, urging the wider range of horizontal signals which is
of benefit to “fringe” area reception, opposed any change in the rules,
at least until some measurements have been analyzed and the result
indicates justification for a change. We are not persuaded that at
present any change in our rules is warranted, and propose none.
90. One party, expressing doubt as.to the meaning of the rule in
the respect mentioned above, suggested that if the rule means that a
power equal to the authorized E.R.P. may be radiated in both planes,
wider spacing between spacings might be necessary in order to avoid
interference. The rule interpretation mentioned is of course correct
(as mentioned above); but, in the absence of further data on this
subject and considering the need for making numerous station assign-
ments, we are not disposed to lengthen spacings beyond those set forth
herein.
XI. Questions Concerning Existing Stations
91. In the July Notice (paragraphs 55 to 57) we raised questions
concerning the relationship between the proposed mileage separation
plan and existing facilities. In this connection, the chief questions
are the following:
(a) What should be done with respect to existing stations which
operate with more than the facilities which will be permitted for new
40 FCC.
279-022—70——_46
694 Federal Communications Commission Reports
stations of their zone and class—e.g., stations in Buffalo, Chicago,
etc., and stations in California, now operating with facilities greater
than 50 kw and 500 feet which will be the maximum for new stations
in Zones I and I-A.
(b) Is there an approximate basis upon which existing stations
may be permitted to expand their facilities herein with respect to
other existing stations.
(c) What should be done with respect to existing stations on Class
B and Class C channels which operate with facilities smaller than the
new minimum adopted. I
92. Commenting parties advanced various ideas in this connection.
It was urged, by WBEN, the license of a Buffalo station operating
with facilities much greater than the Zone I facilities specified here-
in) that existing stations should be given the maximum possible
degree of protection. It was also urged that existing stations, often
deserving of consideration as pioneers in an economically disadvan-
tageous service, should be permitted to go to maximum facilities, on
another channel if necessary, and should not be held strictly to a “go-
no go” standard as new stations should. The NAB took the position
that expansion should be provided for. Some parties urged that
expansion of existing facilities be permitted only where it would not
worsen interference conditions. It was urged that existing Class B
and C stations be required to meet the minimum specified for their
class within a year, or move to a lower class.
Existing stations of great height and power
93. Under our present rules, stations are normally protected against
objectionable interference out to their 1 mv/m contours, with the lo-
cation of both that contour and the various co-channel and adjacent
channel interference contours being determined by use of Figure 1
of § 3.833 of the rules and the interference ratios mentioned above,
(See 8 § 3.203 (a), 8.204(a), and 3.313).7* As to second and third adja-
cent channel assignments (400 and 600 ke removed), 88.813(e) pro-
vides that stations normally will not be assigned at such separations in
the same or nearby cities, but that stations may be authorized in near-
by cities on second or third adjacent channels “where necessary in
order to promote an equitable and efficient distribution of facilities.”
94, As mentioned above, we are herein including in Zone I and
I-A, with limitation on new Class B stations to 50 kw and 500 feet,
large areas which have hitherto been part of “Area 2” with no abso-
lute restriction on height and power. These areas include Illinois,
Indiana, Ohio, western Pennsylvania and New York, a portion of
New England, most of Virginia, parts of Michigan and Wisconsin,
and most of California. In these areas, numerous stations have in the
past been authorized with facilities substantially greater than 50 kw
500 foot maximum adopted here, or its equivalent. In Zone I, assigned
to cities such as Chicago and Buffalo, there are 19 commercial sta-
tions operating with facilities such that, under the new curves adopted
here, their 1 mv/m contours are located further from their transmit-
2 As to the significance of § 3.204(a), see the decision of the Court of Appeals in Amer-
ican Broadcasting-Paramount Theaters, Inc. v. FOC, —— -—— F. 24 , 23 Pike &
Fiseber R.R. 2020 (1962),
40 F.C.
FM Broadcast Rules 695
ters than the 40 mile protected service radius adopted herein as the
basis for assigning Class B stations. These distances range up to 55
miles in the case of a station at Buffalo (operating with 110 kw
E.R.P. and height above average terrain of 1,350 feet). In the Zone
I-A portion of California there are even more such assignments be-
cause of the numerous high elevations, some 35 commercial stations
having 1 mv/m contours more than 40 miles from their transmitters.
The largest such distance is 77 miles in the case of a station at Santa
Barbara (operating with 105 kw and 3,210 feet antenna height). In
new Zone II there are three commercial stations operating with facil-
ities so great that their 1 mv/m contours lie further than 65 miles
from the transmitter. In all of the new zones, there are other stations
which operate with facilities more than the new maxima but less than
the stations just referred to.
95. The existence of these stations raises a question as to how they
should be treated in relation to the new assignment principles adopted
herein.?? On the one hand, it might be argued that they should retain
their present great facilities and be protected on that basis, where
necessary being afforded, by special separation requirements, protec-
tion greater than that afforded generally herein to stations of their
class, This would preserve existing service. On the other hand, it
might be contended that they should be required to cut back in
antenna height and/or power, so as to operate with no more than the
maximum adopted herein for their class. This would have the double
advantage of permitting more new assignments, in some instances,
than would greater protection, and of removing the competitive ine-
quality which exists when a limited number of stations operate with
much greater facilities than others.
96. With respect to the extent of protection to be afforded, we con-
clude that these stations should not be protected to any greater extent
than that afforded by the general mileage separations adopted herein.
This may result in some derogation of existing service in a few cases,
if new assignments are made at or nearly at the minimum spacings
adopted; but, as mentioned before, it is not likely that a large pro-
portion of new assignments will be made as such close spacings. If it
works out that many new assignments are made at near-minimum dis-
tances from existing stations, any resulting loss in service will be
more than counterbalanced by the gain in over-all FM service result-
ing from the new facilities which can thus be provided.® We do not
22 If a limit on facilities of educational stations on the 20 reserved channels is adopted,
a Similar question might arise with respect to six such stations in Zones I and I-A whose
t mv/m contours lie further than 40 miles from their transmitters. This will be dealt
with In the Further Notice to be issued concerning assignment rules for the reserved
channels.
2 As far as possible co- or first adjacent channel interference from new assignments ig
concerned, the possible effect is less than that indicated by the figures as to number of sta-
tions given above. This is because the spacings adopted herein are designed to protect a
contour lower than the 1 meim contour, particularly in the case of Class B stations. In
terms of the possibility of interference within the 1 mv/m contours of these super-
maximum stations, it appears that it exists only with respect to 7 commercial stations in
Zone I, 26 in Zone I-A, and three in Zone IL, and to five educational stations in Zones I
and T—A, even if assignments are made at the minimum applicable spacings and the new
stations operate with maximum facilities. As to second and third adjacent channel inter-
ference, aS already mentioned the impaet of such interference is substantially less than
that from co-channel or first adjacent channel Stations. It would be inappropriate for us
to extend In these cases any greater degree of protection than already decided on with
respect to all stations—simply that the new station must be located outside of the exist-
ing station's protected service radius.
40 F.C.C.
696 Federal Communications Commission Reports
conceive it to be in the public interest to perpetuate the advantage
enjoyed by these super-maximum stations, if it means a restriction on
the provision of needed new facilities and optimum development of
this medium. In considering the question of whether these stations
should be required to cut back in power or height, we must balance
whatever loss of service would be involved against the likely adyan-
tages—more service from new assignments, and removal of competi-
tive inequalities. We do not now decide this question. As set forth in
the Further Notice herein, comments are invited as to whether the
continued existence of these super-maximum facilities tends to thwart
the full development of the FM service, and whether, therefore, steps
E be taken to require these stations to cut back in power or
eight.
97. Channel shifts, Whether or not a Table of Assignments is to be
ultimately adopted herein, applications for changes in channel of
existing stations must necessarily be treated as application for new
stations. This is obviously required if a Table of Assignments is to be
worked out, and is appropriate in any event, since a change in chan-
nel represents a new use of a different frequency, requiring considera-
tion of new potential problems and possible uses of the channel.
Therefore, the rules adopted herein treat applications for change in
the channel of an existing station just like applications for new
stations,
98. Expansion of ewisting facilities. For a number of reasons
mentioned above, it is desirable for existing stations in some situa-
tions to increase their antenna height and/or effective radiated
power. It is for this reason that we have increased the maximum for
facilities in Zone I to 50 kw E.R.P. The question remains as to
whether, considering the large number of stations, especially in
Zone I, which are located at separations with respect to other sta-
tions less than those provided herein, increases could be permitted
for such stations on some appropriate basis. We have concluded that
permitting increases in facilities under these circumstances—i.e.,
changes in height or power which would extend the station’s 1 mv/m
contour further when it is already “short” to other co-channel or
adjacent channel stations—would merely result generally in further
deterioration of existing service, and that such increases should not
be permitted. Accordingly, the rules adopted herein provide that.
increases in facilities will be permitted only where the station apply-
ing meets the required spacings with respect to other stations.** How-
ever, the new rules provide for increases in height accompanied by
decrease in power, or vice versa, where location of the 1 mv/m con-
tour would not lie further from the transmitter than presently.
a Consideration was given to permitting “across the board” increases, where all sta-
tions involved in a chain of short separations apply for equal increases and thus the
ratto between signals would not be changed. But this would inyolve tremendous complica-
tions, as we have seen in the past in connection with the AM Class IV increase to 1 kilo-
watt; and, moreover, would tend to create in some cases an undesirable degree of com-
petitive inequality (for instance, where only one of several stations similarly located
could work out such an “across the board” increase). It is doubtful, in any event. how
many stations could take advantage of such a system.
40 F.C.C.
FM Broadcast Rules 697
99. Changes in transmitter location. Changes in transmitter Joca-
tion will not be permitted where the effect would be to shorten the
spacing toward any co-channel or adjacent channel station (up to 600
ke removed) below that specified herein.
100. Wholesale channel shifts and deletions. Some parties, notably
FM Unlimited, Inc., suggested that existing stations should be moved
in large numbers, in order to effectuate what is believed to be opti-
mum use of the FM band. FM Unlimited urged that: (1) all Class
A stations, and all Class B stations now assigned to the Class A
channels, which would be contiguous from Channel 221 to 240; (2)
stations on Class B and Class C channels (which would be used in
all parts of the country) should be shifted, so that in adjacent metro-
politan areas—e.g., New York-Philadelphia, Chicago-Miiwaukee,
and Los Angeles-San Diego—these stations would operate on chan-
nels no less than 400 ke apart; (3) “non-commercial” operations now
in the commercial FM band (e.g, WNYC-FM, New York City)
should be shifted to the educational band; and (4) where existing
stations would not be accommodated in the course of such shifts,
“marginal” operations, notably stations existing mostly for the pur-
pose of conducting multiplex operations, should be deleted.
101. We have already dealt with, and rejected, some aspects of
this proposal, including the idea of a contiguous band of Class A
channels and of shifting “noncommercial” but non-educational opera-
tions into the reserved channels. With respect to the remainder, we
conclude that the suggestions do not have enough merit to warrant
consideration, at least in this proceeding. The proposal to assign
Class B and Class C channels to the major cities mentioned on a 400
ke separation basis ignores completely the needs of substantial com-
munities in between which would be reduced largely to Class A chan-
nels. With respect to wholesale shifts, this of course would involve
a certain amount of confusion to listeners and broadcasters, and
there is no reason to believe the result would be worth the effort.
102. Continued operation with sub-minimum facilities. As men-
tioned above, one of the problems with the development of FM, par-
ticularly on the channels designed for higher power operations, 1s the
existence thereon of stations operating with very small facilities. This
raises the question of what should be done about, existing stations
operating with less than the minimum herein specified for new sta-
tions of a particular class—a question especially pertinent since we
are adopting as a basis of assignments a mileage separation table
based on maximum facilities for both existing and proposed stations.
103. For the present, we have decided to leave this matter without
taking any action to require existing stations to increase facilities.
First, particularly as to Zone I, it is not clear how many stations can
increase their height and/or power substantially, under our mileage
separation rules adopted herein. It would not be appropriate to adopt
for existing stations a rule which a nwmber of them could not comply
with. Second, where increases are possible, consistent with the rules
adopted herein, we believe stations so situated can be expected to take
steps to improve their facilities voluntarily—especially since they will
40 F.C.C,
698 Federal Communications Commission Reports
be faced with the existence of substantial co-channel and adjacent
channel operations, and will suffer substantial interference from them
if they continue to operate with small height and power. We will con-
tinue to study this situation, and if it appears that a large number
of such stations, which could increase facilities, do not do so, then we
will consider the possibility of show cause proceedings looking to-
ward either an increase in facilities or shift to a Class A channel if
one is available.
£
XII. Pending and Subsequently Filed Applications
104. Adoption of the assignment plan decided upon herein raises
the question of how pending applications, and those to be filed later,
shall be treated during the continuance of this proceeding and work
on a Table of Assignments. It is obvious that work on a Table can-
not proceed satisfactorily while at the same time we continue to grant
applications for facilities which (though they meet our “interim”
processing criteria) do not meet the spacings on which the Table
must be based. The same principle applies even if a Table is not
finally adopted, since we would be making grants in violation of the
spacings which we have concluded to be most appropriate for the
optimum development of this service. Therefore, we have decided
upon the following procedures as appropriate pending final adoption
of a Table or other resolution of this proceeding.
(a) Pending applications for new stations, channel changes, or
‘nereased facilities will be acted on, and new applications will be
accepted for filing, only if they meet the spacings set forth herein
with respect to co-channel and adjacent channel stations (np to 600
ke removed) ,% as well as the other requirements of the rules, e.g. as
to maximum and minimum facilities.
Where app" -ations have been or are accepted for filing but cannot
be granted because of conflict with the mileage separation rules, they
will be held pending until decision as to a Table of Assignments (e.g.,
where two applications meet all mileage separations with respect to
existing stations, but would be at short spacings with respect to each
other, and therefore both cannot be granted). Applications on file
not meeting the spacings with respect to existing stations may be
amended, not withstanding any other provision of the rules. Applica-
tions not meeting the spacings, and not amended by the time this
proceeding is terminated, will then be dismissed.
(b) With respect to pending applications for new stations which
do not meet the spacings, in the preparation of the Table of Assign-
ments every great effort consistent with the public interest will be
made to find an assignment for such applicants—particularly where
their applications were filed before we announced our interim
“freeze” procedure in December, and especially the approximately
80 which were on file before July 5, 1961, when we initiated the pres-
ent over-all consideration of a new FM assigninent system (some of
z The spacings to be complied with are, of course, those with respect to the actual
transmitter sites of existing stations,
40 F.C.C.
FM Broadcast Rules 699
these are in hearing; where applications are mutually exclusive of
course provision will be made for only one assignment, unless the
general priorities adopted for preparation of the Table indicate that
more assignments are warranted). Efforts will also be made to find
assignments (on the same or another channel) to take care of appli-
cations filed from now on, during the pendency of this proceeding
(subject to the conditions as to acceptance mentioned above).
(e) Pending the adoption of rules concerning directional antennas
(see the Further Notice of Proposed Rule Making herein), no appli-
cation will be acted on or accepted where the proposed maximum-to-
minimum ratio exceeds 15 db.
ATL. Relationship With Canadian FM Assignments
105. One of the reasons why a Table of Assignments for U.S. FM
stations is desirable is that Canada has clearly indicated that it in-
tends to promulgate a Table for use in its own assignments, and a
U.S. Table would make it easier for assignments near the border on
both sides to be worked out.
106. The final basis of assignment and protection standards be-
tween U.S. and Canadian FM stations has yet to be worked out in
future conferences. Persons contemplating filing applications for U.S.
FM stations before the final resolution of this proceeding, for places
within 250 miles of the Canadian border, should bear in mind pos-
sible Canadian problems.
XIV. Other Matters
Assignment on the basis of programming; duplication
107. In the earlier Notice, we raised the question of whether
“duplication” by FM stations of the programming of their AM affil-
jates is in the public interest and should be permitted to continue, or
should be limited, if not prohibited entirely. There were numerous
comments on this point, sharply divided. We do not here decide this
matter. We have this question under consideration, and a Notice of
Proposed Rule Making on this subject may be issued shortly.
108. Related to this is the argument, urged by some parties, that
FM assignments should be made on the basis of programming—.¢.,
that Class A, Class B, or Class C assignments should be made on the
basis of a showing by the applicant as to how he will make use of
the assignment sought to serve the public—a matter of particular
importance with Class C stations, designed to serve wide areas. FM
Unlimited’s suggestion that “marginal” stations should be deleted
has also been noted; that party also suggested shifts in station chan-
nel and classification on the basis of the program service rendered.
109. These arguments have some merit, and are being seriously
considered. However, we believe it is not presently appropriate here
—in connection with a proceeding which is basically technical in
nature-_to enter into the complex area of the interrelationship be-
tween the basic assignment process and programming. As mentioned,
we are considering matters of this sort, and it is possible that some
40 F.C.C.
700 Federal Communications Commission Reports
proposal in this area will be forthcoming. Meanwhile, there are other,
existing ways by which this matter can be approached, for example,
filing an application in competition with renewal, where a party
believes the licensee has not adequately programmed in the light of
the type of assignment he holds.
110. We believe it likely, however, that the over-all development
of the FM service would benefit from one change in the assignment
rules which might involve non-technical considerations; and accord-
ingly, it is proposed in the Further Notice adopted herein. This is a
rule providing that, if a Table of Assignments is adopted for FM,
and a construction permit or license is later voluntarily relinquished
by the holder thereof (or is taken away in a revocation or renewal
proceeding), the channel will automatically cease to be assigned to
the community specified in the Table and in the permit or license,
and the Commission will give notice thereof and institute rule making
as to where the channel may be best assigned. In other words, to
the extent channels cease to be used and become available, their use
so as to best serve the public interest should automatically come into
question. This may be of considerable significance, for example, if we
should decide that extensive ANM PM duplication is not in the public
interest, in which case perhaps a number of AM-FM licensees en-
gaged in total or near-total duplication would surrender their author-
izations.
Operator rules and monitors
111. In the 1961 Notice we asked for comments on non-allocation
matters such as operator rules and monitors. There were comments
in both areas. These matters are being handled by consideration sepa-
rate from this proceeding, and action in these areas will be taken
shortly. :
Miscellaneous suggestions and arguments
112. One party asked us to take steps to regulate the quality of
phonograph cartridges and tapes used in FM stations, so as to insure
real “high fidelity”. This is a difficult area, involving technical and
policy considerations. Our principal concern in the technical regu-
lation of broadcast stations has been in the radiated signal and its
possible effects on other users of the radio spectrum, and our rules
and standards have been directed toward providing the best possible
broadcast service by prescribing standards for the transmitting equip-
ment. In the case of the aural broadcast services, this equipment is
considered to extend from the input microphone to the transmitting
antenna. We have not prescribed general standards of quality for
studio equipment or program sources. It would be difficult, if not
impossible, to write detailed rules covering every piece of studio
equipment, recordings, etc., and we do not believe it appropriate to
attempt it. However. it is the licensee’s responsibility to maintain a
technically sound operation in these respects as in others. We have
found that, with respect to technical quality, broadcasters generally
have attempted to provide the best consistent with the economics of
the market and the state of the art. In the past we have in appro-
40 F.C.C.
FM Broadcast Rules 701
priate cases called the attention of licensees to listener complaints
regarding defective studio equipment, and we will continue this
practice.
118. Some other suggestions made by the commenting parties
deserve brief comment. One was that the class designation of FM sta-
tions—“A” and “B”—should be reversed, on the ground that usually
“Class A” like “Grade A,” signifies a preferable things as compared
to “Class B” or “Grade B,” and that time-buyers are misled in this
respect. Were we starting from scratch, this might have some merit.
But, at this point, we believe reversing the classification designations
would cause more confusion than it could be worth. It might also
tend to imply an invidious distinction against “community” stations
which is not warranted. We do not believe the situation generally
is as serious as this party (a Class B licensee) asserts, or that we
would be warranted in taking this action.
114. The same party also protested against the “inequality” caused
in his area by the fact that he, as an Area 1 Class B station, must
compete with more powerful Area 2 stations located fairly close by
and penetrating his market. This kind of “inequality” of course will
exist wherever there are two zones, between stations close to the line
between them; and, indeed, a certain amount of inequality is inevi-
table unless Ai stations are to operate with approximately the same
facilities. We do not believe that from the standpoint of the over-all
public interest this is a serious problem, and, in any event, to the
extent it is, the “inequality” is outweighed by the desirability of
having different zones to reflect different population and assignme:t
conditions.”
115. One party urged that the interference burden on Class B sta-
tions in the same market from Class A stations—which is said to
affect some more than others by virtue of their position in the band
with respect to the Class A channels—should be equalized by reas-
signing the “A” stations in a given market at strict 1600 ke intervals,
which assertedly would result in each Class B station having one,
but only one, Class A adjacent channel interference problem. "There
is no specific data given as to how this would work and obviously it
would cut down the availability of Class A assignments. Therefore,
and also because of the undesirability of shifting existing stations
mentioned above, we must reject this suggestion.
116. Two other suggestions relate to assignments. One, from a
Richmond, Va., Class B station, is that a “Class C” station in that
city—the state capital—should have a 100 mile protected service
radius. In this respect we must adhere to our earlier judgment, that
only Class B stations should be assigned in Zone I; the public interest
will be better served by the more numerous assignments thus made
possible. On the other hand, a Palo Alto, Calif., Class A station, which
has a pending application for a Class B assignment which would
cause objectionable interference to two adjacent channel San Fran-
2% The particular area involved in this comment (Scranton-Wilkes-Barre in Area 1, and
Wiillamsport in Area 2), will be of course now entirely within Zone I. Whether this will
enable the Scranton-Wiikes-Barre station to improve its competitive position does not
appear, but we have provided for an increase in the Zone I maximum.
40 F.C.C.
702 Federal Communications Commission Reports
cisco stations, argues against any restrictions whatsoever (asserting
the need for an increase in its power in order to provide for stereo
operation). We have at length herein discussed why more protection,
and a more orderly development of the FM service, is desirable, and
therefore this contention must be rejected.?*
117. Intercollegiate Broadcasting System, Inc, (an organization of
“campus” radio stations) urged that, if we do not adopt its proposal
for commercial but “non-profit” operation in the educational band
we permit such operation by 10 watt stations to be assigned on the
20 Class A commercial channels. This suggestion must be rejected,
because such use of the Class A channels—on which numerous as-
signments must be made to accommodate the needs of smaller com.
munities—is completely inconsistent with efficient use of these chan.
nels.
118. In the July Notice, we proposed to adopt for the purpose of
dealing with multiple ownership situations, a rule that commonly
owned stations would not be authorized where there would be overlap
of the 2 mv/m contours. This matter is not dealt with herein, being
currently the subject of a rule-making proceeding regarding overlap
generally.
119. A number of parties urged that before adopting rules in the
FM station assignment area, we should put out a further notice of
rule making, with more specific proposals. In light of our decision
herein—which is for the most part along the lines indicated in the
July Notice and the appendix thereto—we are of the view that except
te the extent mentioned above and reflected in the Further Notice
below, further rule making is unnecessary and would not be in the
public interest. Interested parties have had ample opportunity to
comment on many aspects of FM allocations, including specific pro-
posals of the sort adopted herein. Further opportunity, which would
involve necessarily considerable time, need not and should not be
afforded except in the respects mentioned. The time has come when
the future course of the FM service and FM station assignments must
be determined. S
XV. Conclusions and Order
120. For reasons set forth above, we have decided upon certain
changes in the rules relating to the FM broadcast service, which are
adopted herewith. In certain respects—the procedure relating to ac-
ceptance and action on applications pending the final resolution of
this proceeding, and the showing to be required in applications spec-
ifying directional antennas—these are procedural, and therefore no
notice of proposed rule making is required, under the provisions of
Section 4 of the Administrative Procedure Act. In any event, the
public interest clearly. requires that these actions be taken. Clearly,
it would be inappropriate to accept or grant applications conflicting
with the mileage separations as to existing stations or other standards
adopted herein. If work on a Table of Assignments is to proceed in
an orderly fashion, any grant must be subject to a change in channel
m It may be that the increase in maximum Class A power adopted herein will solve
these problems without change in channel.
40 F.C.C.
FM Broadcast Rules 703
if more over-all assignment efficiency would result. As to the direc-
tional antenna requirements, it would be inappropriate to grant ap-
plications likely conflicting with a standard which may be adopted,
or to accept applications not even complying with the most lenient
standard under consideration. In order to avoid a flood of non-com-
plying applications, it is necessary to make the Procedural rule con-
cerning processing (§1.856) effective as quickly as possible.
121. In view of the foregoing, and pursuant to authority contained
n Sections 4(i) and 303(r) of the Communications Act of 1984, as
amended, lt is ordered, That, effective August 8, 1962, Section 1.356
of the Commission’s Rules Js amended as set forth in Appendix A
hereto; and `
122. It is further ordered, That, effective September 10, 1962, the
provisions of Subparts B and C of Part 3 of the Commission’s Rules
Are amended as set forth in Appendix B hereto.
FEDERAL COMMUNICATIONS COMMISSION,
Ben F. Warre, Acting Secretary.
STATEMENT OF COMMISSIONER Freperick W. Ford IN Wurcn
Cuatrman Minow Concurs
I am in agreement with the Report and Order, but I would not
favor the issuance of it or the Further Notice of Proposed Rulemak-
ing at this time. I would delay the issuance of the Report and Order
until a tentative allocation table could be prepared and included in
the Notice of Proposed Rulemaking which should be released simul-
taneously with the Report and Order.
APPENDIX À
Effective August 8, 1962, paragraph (e) of $ 1.856, and the Note following
that section, are amended to read as follows:
§ 1.356 Processing of FM AND NONCOMMERCIAL EDUCATIONAL FM BROADCAST
APPLICATIONS,
* D * * D * D
(e) Except as provided in the Note to this section, if, upon examination, the
Commission finds that the public interest, convenience and necessity will be
served by the granting of an application for FM broadcast facilities (Class A,
Class B, Class C or noncommercial educational), the same will be granted.
If, on the other hand, the Commission is unable to make such a finding and
it appears that a hearing may be required, the procedure set forth in § 1.862
will be followed.
Nore.—During further consideration of the matters and issues in Docket No. 14185
(pertaining to the revision of the FM broadcast rules), applications for FM broadcast
authorizations (on both commercial and noncommercial educational channels, whether in
or out of hearing status, and regardless of the date they were or may be tendered for
filing) will be subject to the following procedures, notwith standing any provision of the
FM broadcast rules or of this section to the contrary:
(a) Mazimum and minimum facilities. No application for construction permit
for a new station, change in channel, or increase in facilities on the same
channel will be granted, and after August 8, 1962, no such application will be
accepted for filing, unless the facilities of the proposed station meet the maxi-
mum and minimum requirements for facilities for stations of its class set forth
in § 3.204, § 3.209, or § 3.504 of this chapter, as amended July 25, 1962, effective
September 10, 1962: Provided, however, That, no provisions as to minimum
40 F.0.C.
704 Federal Communications Commission Reports
facilities apply to noncommercial educational stations operating on the chan-
nels specified in § 3.501 of this chapter, or to grant or acceptance of applications
by any existing station for increase in facilities on its present channel: and
no provisions as to maximum facilities apply to noncommercial educationa.
stations on channels 201 to 217, inclusive, set forth in § 3.501 of this chanter,
(b) Directional antennas. No application for construction permit for a new
station, change in channel, or existing facilities on the same channel will be
granted, and after August 8, 1962, no such application will be accepted for
filing, where it proposes a directional antenna with a maximum-to-minimum
ratio of more than 15 db.
(c) Minimum mileage separations. The minimum mileage separations set
forth in $ 3.205 of this chapter (as amended July 25, 1962, effective Septem-
ber 10, 1962) apply to all applications for construction permits for new stations,
changes in channel, or increases in facilities, on FM channels 221 through 300
listed in § 3.201 of this chapter, as follows:
(1) No application will be accepted for filing after August 8, 1962, unless the
proposed station is located so as to meet said separations with respect to all
co-channel and adjacent-channel (up to 600 Feis removed) stations authorized
as of August 8, 1962;
(2) No application (regardless of when filed) will be granted unless the
proposed station is located so as to meet said separations with respect to all
co-channel and adjacent-channel (up to 600 ke/s removed) stations authorized
or proposed in other now pending or subsequently accepted applications.
(3) Applications on file or later accepted, which cannot be granted pursuant
to the provisions of paragraphs (a), (b), or (e) of this note (eg, applica-
tions involving short separations only with facilities proposed in other pend-
ing applications), will be held pending.
(d) Consideration pending decision as to an FH Table of Assignments.
Pending decision as to the matter of adopting a Table of Assignments for the
80 FM commercial channels, and preparing and promulgating such a Table
if it is concluded to be in the public interest, applications which ure now on
file or are later accepted, but which cannot be granted under the provisions of
paragraphs (a), (b), or (c) of this note will be held pending. In the prepara-
tion of a Table, effort will be made to find assignments to accommodat such
applications, on the same or other channels (except where they are cleariy
mutually exclusive with each other, such as two applications for the same
channel in the same small community, in which only one FM assignment would
be warranted under general assignment principles). Particular effort will be
made to find assignments to take care of requests in applications on file as of
the date of the adoption of this note (July 25, 1962) and especially, those
applications filed before July 5, 1961 (the date of release of the document
instituting the over-all FM allocation proceeding). If and when a Table is
adopted, applications inconsistent therewith (as then on file, taking into ac-
count amendments, if any) or otherwise inconsistent with the provisions of sub-
part B of Part 8 of this chapter will then be dismissed. If it is decided not to
adopt a Table, consideration will be given as to how to treat applications then
on file which involve no conflicts with existing stations but only with other
nding applications,
pon deent of applications. Notwithstanding any other provision of this
part, any application for FM broadcast facilities may be amended, at any time
pending final disposition of Docket No. 14185, with respect to channel, height,
power, or transmitter location, so as to bring it into compliance with the rules
adopted in Part 3 of this chapter on July 25, 1962 (effective September 10,
1962), or a tentative Table of Assignments when proposed. `.
(£) Applications for changes in transmitter sites. Applications for changes
in the transmitter sites of existing stations operating on channels 221 through
300 specified in § 3.201 of this chapter will not be granted, and after August 8,
1962, will not be accepted for filing, where grant thereof would shorten the
mileage separation between the applicant station and other co-channel or
adjacent-channel stations, and the resulting spacing would be Jess than that
specified in $ 3.205 of this chapter (as amended July 25, 1962, effective
eptember 10, 1962).
š Ta) e educational stations. With respect to grant and (after
August 8, 1962) acceptance of applications for construction permits for new
40 FCC.
FM Broadcast Rules 705
or changed facilities on the channels reserved in § 3.501 of this chapter for
ueational use, the following restrictions wi i iti
ot ed in paragraph (b) of this Note) : Will apply in addition to those
a) Applications for facilities on channels 218, 219, and 220 must meet the
Ën Dei, requested t
G t sted must not exceed the maxim facilities speci
in § 8.209 of this chapter (as amended July 25, 1962, effective gina weeny
1962) for Class B or Class C commercial stations, depending on the zone in
which the requested facilite: would be located. >
Gi requested facilities must be located, with sisting
a ajacent-channel stations on channels 221, 222, and 223, Strana eso than Ee
minimum mileage separations specified for stations of their class in §§ 3.205
and, E of this chapter( as amended July 25, 1962, effective September 10,
962). S
1 (iii) Where the application is for change in transmitter site, the move must
not shorten the separation between the station and other co-channel and
adjacent-channel stations, if the result would be a spacing less than that speci-
fied in § 3.205 of this chapter (as amended July 25, 1962, effective Septem-
per 10, 1002) Se
(2) No app ication for facilities on any channel cified in H i
chapter will be granted (or accepted after Angust 8. 1962) Hy esas
requested would cause objectionable interference within the 1 mv/m contour
of any co-channel or adjacent-channel station. The following standards shall be
used to determine the existence of objectionable interference:
(i) The distance to the 1 mv/m contour shall be determined by use of
Figure 1 of § 3.333 of this chapter (as amended July 25, 1962, effective
September 10, 1962).
(ii) The distance to the applicable interference contour shall be determined
by the (50,10) curve published with the Commission’s Order, FCC 61-1447,
adopted December 6, 1961, setting forth the interim procedure for processing
FM applications and amending $ 1.356.
(iii) Objectionable interference will be considered to exist where, on the
pasis of the curves referred to in this subparagraph, the undesired signal of
a co-channel signal exceeds one-tenth of the desired signal, the undesired
signal of a station 200 ke/s removed exceeds one-half of the desired signal,
the undesired signal of a station 400 kc/s removed exceeds 10 times the
desired signal, or the undesired signal of a station 600 ke/s removed exceeds
100 times the desired signal.
APPENDIX B
Effective September 10, 1962, subparts B and C of Part 3 of the Rules are
amended as set forth below.
1. In “Classification of FM Broadcast Stations and Allocation of Frequencies,”
8§ 8.202-3.205 are deleted, and new §§ 3.202-3.210 are added, as follows:
$ 3.202 INTERNATIONAL AGREEMENTS AND OTHER RESTRICTIONS ON USE OF
CHANNELS.
(a) Authorizations issued by the Commission for FM broadcast facilities
will be subject to the provisions of any agreements entered into by the United
States with Canada concerning FM assignments and authorizations. The Com-
mission may decide after consultation with Canada that an application should
not be granted; or if, pursuant to an agreement providing for timely objection
after grant, Canada files such objection, the Commission may on its own
motion set aside the grant pending consideration. The Commission will give
notice of the filing of such objections.
(b) The frequency 89.1 Mc/s (channel 206) is reserved in the New York City
metropolitan area for the use of the United Nations with the equivalent of
an antenna height of 500 feet above average terrain and effective radiated
power of 20 kilowatts, and the Commission will make no assignments which
would cause objectionable interference with such use.
(e) In Alaska, the frequency band 88-100 Mc/s is allocated exclusively to
Government radio services and the non-Government fixed service. The fre-
quencies 88.1 through 99.9 Mc/s (channels 201 through 260) will not be assigned
in Alaska for use by FM broadcast stations,
40 F.C.C.
706 Federal Communications Commission Reports
(d) In Hawaii, the frequency band 98-108 Mc/s is allocated for non-
broadcast use. The frequencies 98.1 through 107.9 Mc/s (channels 251 through
800) will not be assigned in Hawaii for use by FM broadcast stations.
§ 3.203 ZONES.
For the purpose of allocation and assignment, the United States is divided
into three zones as follows:
(a) Zone 1 consists of that portion of the United States located within the
confines of the following lines drawn on the United States Albers Equal Area
Projection Map (based on standard parallels 2914° and 45%°; North American
datum): Beginning at the most easterly point on the State boundary line
between North Carolina and Virginia; thence in a straight line to a point on
the Virginia, West Virginia boundary line located at North latitude 87° 49
and West Longitude 80° 12’ 30”; thence westerly along the southern boundary
lines of the States of West Virginia, Ohio, Indiana. and Illinois to a point at
the junction of the Hlinois, Kentucky, and Missouri State boundary lines;
thence northerly along the western boundary line of the State of Illinois to
a point at the junction of the Illinois, Iowa, and Wisconsin State boundary
lines; thence easterly along the northern State boundary line of Illinois to
the 90th meridian; thence north along this meridian to the 43.5° parallel;
thence east along this parallel to the Tist meridian; thence in a straight line
to the intersection of the 69th meridian and the 45th parallel; thence east along
the 45th parallel to the Atlantic Ocean. When any of the above lines pass
through a city, the city shall be considered to be located in Zone I. (See
Figure 1 of § 3.699.)
(b) Zone IA consists of that portion of the State of California which is
located south of the 40th parallel.
(e) Zone IT consists of Alaska, Hawaii, Puerto Rico, the Virgin Islands, ang
the rest of the United States which is not located in either Zone I or Zone LA.
$ 3.204 CLASSES OF COMMERCIAL CHANNELS, AND STATIONS OPERATING THEREON,
(a) Class A channels and stations.
(1) Except as provided in § 3.202, the following frequencies are designated
as Class A channels and are assigned for use, in all zones, by Class A stations
only:
Channel
No.
221
224
228
232
Channel
No.
Frequency (Mc) Frequency (Mc)
(2) A Class A station is a station which operates on a Class A channel, and
is designed to render service to a relatively small community, city, or town,
and the surrounding rural area.
(3) A Class A station will not be authorized to operate with effective
radiated power greater than 3 kilowatts (4.8 dbk), and the coverage of a
Class A station shall not exceed that obtained from 3 kilowatts effective radi-
ated power and antenna height above average terrain of 300 feet. For provi-
sions concerning minimum facilities, and concerning reduction in power where
antenna height above average terrain exceeds 300 feet, see § 3.209.
(b) Class B-C channels and Class B and Class O stations.
(1) Except for the channels specified in paragraph (a) (1) of this section,
all of the channels listed in $ 3.201 from 222 through 300 (92.8 through
107.9 Me/s) are classified as Class B-C channels, and (subject to the restric-
tions set forth in $ 3.202) are assigned for use in Zones I and I-A by Class B
stations only, and for use in Zone II by Class C stations only (there are no
Class © stations in Zones I or I-A and no Class B stations in Zone II).
40 F.C.C,
FM Broadcast Rules 707
(2) A Class B station is a Station which operates on a Class B-C channel
gone I or Zone I-A, and is designed to render service to a sizable com-
munity, city, or town, or to the principal city or cities of an urbanized area,
and to the surrounding area.
(3) With respect to Class B stations authorized after September 10, 1962.
no such station will be authorized with effective radiated power greater than
50 kilowatts (17 dbk), and the coverage of a Class B station authorized after
that date shall not exceed that obtained from 50 kilowatts effective radiated
ower and 500 feet antenna height above average terrain. For provisions
concerning Minimum power, and concerning reduction in power where antenna
peight above average terrain exceeds 500 feet, see $ 3.209.
(4) A Class C station is a station which operates on a Class B-C channel
in Zone II, and is designed to render service to a community, city, or town.
and large surrounding area.
(5) With respect to Class C stations authorized after September 10. 1962.
o such station will be authorized with effective radiated power greater than
100 kilowatts (20 dbk), and the coverage of a Class C station authorized after
that date shali not exceed that obtained from 100 kilowatts effective radiated
power and antenna height above average terrain of 2,000 feet, For provisions
concerning minimum power, and reduction in power where antenna height
above average terrain exceeds 2,000 feet, see § 3.209. š
$ 3.205 MINIMUM MILEAGE SEPARATIONS BETWEEN CO-CHANNEL AND ADIACENT-
CHANNEL STATIONS ON COMMERCIAL CHANNELS.
(a) No application for a new station, change in the channel of an existing
station, or (except as provided in paragraph (b) of this section) increase in
antenna height or effective radiated power, or change in location of an existing
station, will be granted unless the proposed facilities will be located at least
as far from the transmitter sites of other co-channel and adjacent-chaunei
stations (both existing and proposed) as the distances specified in this para-
graph. Proposed stations of the respective classes shown in the left-hand
column of the following table shall he located no less than the distance shawn
from co-channel statious and first adjacent-channel stations (200 ke removed)
and second and third adjacent-chamnel stations (400 and 600 ke removed)
of the classes shown in the remaining columns of the table. The distances
shown between stations of different classes apply regardless of whicb is the
proposed station under consideration (e.g., distances shown from a new Class A
station to an existing Class © station are also the distances between a new
Class C and an existing Class A station). The distances between Class B and
Class C stations apply only across zone lines. The adjacent-channel spacings
listed also apply: (1) to applications for noncommercial educational facilities
on Channels 218, 219, or 220, with respect to other stations on Channels 221,
222, or 223; (2) to applications for facilities on Channels 221, 222, or 223 with
respect to noncommercial educational stations on Channels 218, 219, or 220
(for classification of noncommercial educational stations, see § 3.504).
Class of station and frequency separation (ke/s)
Class A Class B Class C 10-watt educational
Class of Sta.
Co- 200 400 600 Co- 200 400 600 Co- 200 400 600 Co- 200 400 600
Ch. Ch. Ch. Ch.
Class ---- 65 40 40 -.. 105 65 65 30 15 15
Class 170 135 65 65 --- 40 40
180 150 65 65 — 65 65
Class C $ -
10-watt educational... _... _.. e --- e en eee <. e e < e e cse oe
NorE.—Intermediate frequency amplifiers of most FM broadcast receivers are designed to operate on
10.7 megacycles, For this reason the assignment of two stations in the same area, one with a frequency of
10.6 or 10.8 megacycles removed frorm that of the other, will be avoided if possible.
(b) Where an existing station is located less than the minimum distances
specified in paragraph (a) of this section with respect to co-channel or
adjacent-channel stations:
40 F.C.C.
708 Federal Communications Commission Reports
(1) It may apply for increases in antenna height, or in effective radiated
power up to the maximum specified in § 3.204 for its class, if the application
for increase is accompanied by a request to decrease power or antenna height
so that the station’s 1 mv/m contour (located pursuant to Figure 1 of § 3.333)
will be no further from the station’s transmitter than with its present facilities,
(2) It may apply for permission to move transmitter site, but this will not
be granted if it would increase the amount by which the station is located at
sub-standard separation.
(e) The zone in which the transmitter of an FM station is located or
proposed to be located determines the applicable rules with respect to minimum
required spacings.
§3.206 REFERENCE POINTS AND DISTANCE COMPUTATIONS.
{a) Station separations in licensing proceedings shall be determined by the
distance between the coordinates of the proposed transmitter site in one com-
munity and the coordinates of an authorized site for the pertinent channel in
the other community.
(b) The distance between reference points is considered to be the length of
the hypotenuse of a right triangle, one side which is the difference in latitude
of the reference points and the other side the difference in longitude of the two
reference points, and shall be computed by the method set forth in this para-
graph. (This method is appropriate for determining distances up to 220 miles,
and for such distance will normally be more accurate than using spherical trig-
onometry without correction for the spheroidal shape of the earth. However, its
accuracy deteriorates rapidly at distances beyond 300 miles and this method
should not be used to compute greater distances.)
(1) Determine the difference in latitude and the difference in longitude
between the two reference points, Convert these two differences into degrees
and decimal parts of a degree in accordance with Table I of § 3.698.
(2) Determine the middle latitude of the two reference points to the nearest
second of latitude (average the latitudes of the two points).
(3) Multiply the difference in latitude by the number of miles per degree of
latitude difference obtained from Table II of § 3.608 for the appropriate middle
latitude (interpolate linearly). This determines the north-south distance in
statute miles (La).
Nove.—In determining necessary distance computations for Alaska, Hawaii, and the
Territories, the appropriate mileage per degree may be obtained by linear interpolation
of the data given on pages 1246 and 1247 of the tables in publication a. O. No. 9 (Bowditch-
American Practical Ñavigator—1958 Edition) of the U.S. Navy Department, Hydrographic
Hie This publication may be purchased from the Government Printing Office, Washington
Oy
(4) Multiply the difference in longitude by the number of miles per degree
of longitude difference obtained from Table III of § 3.698, for the appropriate
middle latitude (interpolate linearly), This determines the east-west distance
in statute miles (Lo).
(5) Determine the distance between the two reference points by the square
root of the sum of the squares of the distances obtained in subparagraphs (3)
and (4) of this paragraph, using sufficient decimal figures to determine the
distance to the nearest mile; i.e.,
D= Ulli
where:
D
Distanee in statute miles,
L, orth-South distance in statute miles,
L.==North-South distance in statute miles,
§ 3.207 PROJECTION FROM INTERFERENCE
(a) Permittees and licensees of FM broadcast stations are not protected from
any interference which may be caused by the grant of a new station, or of au-
thority to modify the facilities of an existing station, in accordance with the
provisions of this subpart.
(b) The nature and extent of the protection from interference accorded to
FM broadcast stations is limited solely to the protection which results from the
minimum assignment and station separation requirements and the rules. with
respect to maximum powers and antenna heights set forth in this subpart.
40 FCC.
FM Broadcast Rules 709
§ 3.208 STATION LOCATION AND PROGRAM ORIGINATION.
(a) (1) Except as provided in paragraph (b) of this section, each FM broad-
cast station will be licensed to serve primarily a particular city, town, political
subdivision, or community which will be specified in the station license and the
station will be considered to be located in such place.
(2) Each station shall maintain a studio, which will be known as the main
studio, in the place where the station is located: Provided, That the main stu-
dio may be located at the transmitter site whether or not the transmitter site
js in the place where the station is located.
(3) A majority (computed on the basis of duration and not number) of a sta-
tion’s programs or, in the case of a station affiliated with a network, two-thirds
of such station's non-network programs, whichever is smaller, shall originate
from the main studio or from other studios or remote points situated in the
lace where the station is located.
(b) (1) Stations will be licensed to serve more than one city, town, political
subdivision, or community only where a satisfactory showing is made that each
such place meets all the requirements of this subpart with respect to the loca-
tion of main studios; that the station can and will originate a substantial num-
per of local live programs from each such place; and that the requirements as
to origination of programs contained in paragraph (a) of this section would
place an unreasonable burden on the station if it were licensed to serve only
one city, town, political subdivision, or community.
(2) A station licensed to serve more than one place shall be considered to be
located in and shall maintain main studios in each such place.
(8) With respect to such station, the requirements in paragraph (a) of this
section as to origination of programs shall be satisfied by the origination of pro-
grams from any or all of the main studios, other studios, or remote points situ-
ated in any or all of the places in which the main studios are located.
(e) The transmitter of each FM broadcast station shall be so located that,
on the basis of the effective radiated power and antenna height above average
terrain employed, a minimum field strength of 70 decibels above one microvolt
per meter, or 3.16 millivolts per meter, will be provided over the entire principal
community to be served,
§ 3.209 POWER AND ANTENNA HEIGAT REQUIREMENTS.
(a) Minimum requirements.
(1) Except as provided in paragraph (b)(2) of this section, the minimum
effective radiated power shall be, for stations of the respective classes, as
follows:
100 watts (—10 dbk).
5 kw (7 dbk).
10 kw (10 dbk).
(2) No minimum antenna height average terrain is specified.
(b) Afavimum power and antenna height.
(1) The maximum effective radiated power in any direction, and maximum
antenna height for equivalence purposes, shall be as follows for the various
classes of stations:
8 Maximum antenna
Maximum power height (feet above
average terrain)
3kw (4.8 dbk). _ 300
50 kw (17.0 dbk) 500
100 kw (20.0 dbk; 2, 000
(2) Antenna heights may be used exceeding those specified in this paragraph
for equivalence purposes, provided effective radiated power is reduced in the
amount less than the normal minimum specified in paragraph (a) (1) of this
Where, under Figure 3 of § 3.333, effective radiated power must be reduced to an
amount less than the normal minimum specified in paragraph (a) (1) of this
section for the class of station involved, the effective radiated power determined
by Figure 8 of $ 8.388 shall be the minimum for the station involved.
40 F.C.C.
279-022—70—_47
710 Federal Communications Commission Reports
(c) Determination of applicable rules. The zone in which the transmitter of
an FM station is located or proposed to be located determines the applicable rules
with respect to the class of station, and thus the minimum and maximum require.
ments as to facilities.
(d) Existing stations. Pending resolution of the issues in Docket No. 14185
stations authorized as of September 10, 1962, which do not conform to the re.
quirements of this section, may continue to operate as authorized; but any ap-
plication to change facilities will be subject to the provisions of this section,
except that the minimum power specified in paragraph (a) of this section shall
not apply to an application to inerease facilities.
§ 3.210 ADMINISTRATIVE CHANGES IN AUTHORIZATIONS.
(a) In the issuance of FM broadcast station authorizations, the Commission
will specify the transmitter output power and effective radiated power in ae.
cordance with the following tabulation:
Rounded out to
nearest figure
Power (watts or kw): (watts or ku)
1 to 8. 05
.1
.Š
1
Š
--- 10
(b) Antenna height above average terrain will be specified in accordance with
the following tabulation :
Rounded out to
nearest
Antenna height above average terrain : Ze
1
5
10
$ 3.251 [Deletion]
2. In “Equipment,” § 3.251 is deleted.
8. In “Technical Operation,” $ 3.267(a) (3) is amended to read as follows:
$ 3.267 OPERATING POWER; DETERMINATION AND MAINTENANCE OF.
(a) +*+
(8) The efficiency factor, F, shall be established by the transmitter manufac-
turer for each type of transmitter for which he submits data to the Commis-
sion, over the entire operating range of powers for which the transmitter is
designed, and shall be shown in the instruction books supplied to the customer
with each transmitter. In the case of composite equipment, the factor F shall
be furnished to the Commission with a statement of the basis used in determin-
ing such factor. 2
§ 3.272 [Deletion]
8a. In “Technical Operation,” § 3.272 is deleted.
§ 3.301 [Deletion]
4. In “FM Technical Standards,” § 3.301 is deleted.
5. In “FM Technical Standards,” $ 3.310 and 3.311 are amended to read as
follows:
83310 DEFINITIONS.
(a) Frequency modulation.
Antenna height above average terrain. The average of the antenna heights
above the terrain from 2 to 10 miles from the antenna for the eight directions
spaced evenly for each 45 degrees of azimuth starting with True North. (In
general, a different antenna height will be determined in each direction from
the antenna. The average of these various heights is considered the antenna
height above the average terrain. In some cases less than 8 directions may be
used. See §3.813(d).) Where circular or elliptical polarization is employed, the
antenna height above average terrain shall be based upon the height of the radi-
ation center of the antenna which transmits the horizontal component of
radiation.
40 F.C.C,
FM Broadcast Rules 711
Antenna power gain. The square of the ratio of the root-mean-square free
space field strength produced at one mile in the horizontal plane, in millivolts
per meter for one kilowatt antenna input power to 137.6 mv/m. This ratio should
be expressed in decibels (db). (If specified for a particular direction, antenna
ower gain is based on the field strength in that direction only.)
Center frequency, The term “center frequency means:
(1) The average frequency of the emitted wave when modulated by a sinus-
oidal signal.
(2) The frequency of the emitted wave without modulation.
Effective radiated power. The term “effective radiated power” means the prod-
uct of the antenna-power (transmitter output less transmission line loss)
times (1) the antenna power gain, or (2) the antenna field gain squared. Where
circular or elliptical polarization is employed, the term effective radiated power
js applied separately to the horizontal and vertical components of radiation.
For allocation purposes, the effective radiated power authorized is the horizon-
tally polarized component of radiation only.
FM Broadcast band, The band of frequencies extending from 88 to 108 mega-
eycles per second, which includes those assigned to noncommercial educational
proadeasting.
FM broadcast channel. A band of frequencies 200 ke/s wide and designated
by its center frequency. Channels for FM broadcast stations began at 88.1 Mc/s
and continue in successive steps of 200 ke/s to and including 107.9 Mc/s.
FM Broadcast station. A station employing frequency modulation in the FM
broadcast band and licensed primarily for the transmission of radiotelephone
emissions intended to be received by the general public.
Field strength. The electric field strength in the horizontal plane.
Free space field strength. The field strength that would exist at a point in the
absence of waves reflected from the earth or other reflecting objects.
Frquency Modulation. A system of modulation where the instantaneous radio
frequency varies in proportion to the instantaneous amplitude of the modulat-
ing signal (amplitude of modulating Signal to be measured after pre-emphasis,
if used) and the instantaneous radio frequency is independent of the frequency
of the modulating signal.
Frequency swing. The instantaneous departure of the frequency of the emitted
wave from the center frequency resulting from modulation.
Multiplex transmission. The term “multiplex transmission” means the simul-
taneous transmission of two or more signals within a single channel. Multiplex
transmission as applied to FM broadcast stations means the transmission of
facsimile or other signals in addition to the regular broadcast signals.
Percentage modulation, The ratio of the actual frequency swing to the fre-
quency swing defined as 100 percent modulation, expressed in percentage. For
FM broadcast stations, a frequency swing of +75 kilocycles is defined as 100
percent modulation.
(b) Stereophonic broadcasting.
Cross-talk. An undesired signal occurring in one channel caused by an electri-
cal signal in another channel.
FM stereophonic broadcast. The transmission of a stereophonic program by a
single FM broadcast station utilizing the main channel and a stereophonic sub-
channel.
Left (or right) signal. The electrical output of a microphone or combination
of microphones placed so as to convey the intensity, time, and location of
sounds originating predominantly to the listener’s left (or right) of the center
of the performing area.
Left (or right) stereophonic channel. The left (or right) signal as electrically
reproduced in reception of FM stereophonic broadcasts.
Main channel. The band of frequencies from 50 to 15,000 cycles per second
which frequency-modulate the main carrier.
Pilot subcarrier. A subcarrier serving as a control signal for use in the recep-
tion of FM stereophonie broadcasts.
Stereophonic separation. The ratio of the electrical signal caused in the right
(or left) stereophonic channel to the electrical signal caused in the left (or
right) stereophonic channel by the transmission of only a right (or left) signal.
40 F.C.C.
712 Federal Communications Commission Reports
Stereophonic subcarrier. A subcarrier having a frequency which is the second
harmonic of the pilot subcarrier frequency and which is employed in FM stereo-
phonic broadcasting.
Stereophonic subchannel. The band of frequencies from 23 to 53 kilocreles per
second containing the stereophonic subcarrier and its associated sidebands.
(c) Facsimile.
Available line. The portion of the total length of scanning line that can be
used specifically for picture signals.
Index of cooperation. The product of the number of lines per inch, the avail-
able line length in inches, and the reciprocal of the line-use ratio (e.g.
1058.2 X8/7=984).
J Line-use ratio. The ratio of the available line to the total length of scanning
‘ine.
Optical density, The logarithm (to the base 10) of the ratio of incident to
transmitted or reflected light.
Rectilinear scanning. The process of scanning an area in a predetermined
sequence of narrow straight parallel strips.
83311 FIELD STRENGTH CONTOURS.
(a) Applications for FM broadcast authorization must show three field
strength contours, These are the 70 dbu (3.16 mv/m), 60 dbu (1 mv/m), and
34 dbu (50 uv/m). These contours indicate only the approximate extent of cov-
erage over average terrain and in the absence of interference. Under actual
conditions, the true coverage may vary greatly from these estimates because
the terrain over any specific path is expected to de different from the average
terrain on which the field strength chart was based. Because of these factors
the estimated contours give no assurance of service to any specific percentage
of receiver locations within the distances indicated.
(b) The field strength contours provided for in this section shall be consid-
ered for the following purposes only:
(1) In the estimation of coverage resulting from the selection of a particular
transmitter site by an applicant for an FM broadcast station.
SEN In connection with problems of coverage arising out of application of
240,
(3) In determining compliance with paragraph (a) of this section concern-
ing the minimum field strength to be provided over the principal community to
be served.
6. In “FM Technical Standards,” present § 3.313 is deleted, and new §3.313
is added, as follows:
§ 8.313 PREDICTION OF COVERAGE.
(a) All predictions of coverage made pursuant to this section shall be made
without regard to interference and shall be made only on the basis of estimated
field strengths.
(b) Predictions of coverage shall be made only for the same purposes as
relate to the use of field strength contours as specified in §3.311. `
(e) (1) In predicting the distance to the field strength contours, the F (50, 50)
field strength chart, Figure 1 of § 3.333, shall be used. The 50 percent field
strength is defined as that value exceeded for 50 percent of the time. The F (50,
50) chart gives the estimated 50 percent of the locations in decibels above 1
microvolt per meter. The chart is based on an effective power of 1 kilowatt
radiated from a half-wave dipole in free space, which produces an unattenuated
field strength at 1 mile of about 103 db above 1 microvolt per meter (137.6 mil-
livolts per meter).
(2) To use the chart for other powers, the sliding scale associated with the
chart should be trimmed and used as the ordinate scale. This sliding scale is
placed on the chart with the appropriate gradation for power in line with the
horizontal 40 db line on the chart. The right edge of the scale is placed in line
with the appropriate antenna height gradations, and the chart then becomes
direct reading (in uv/m and in db above 1 uv/m) for this power and antenna
height. Where the antenna height is not one of those for which a scale is pro-
vided, the signal strength or distance is determined by interpolation between
the curves connecting the equidistant scale. Dividers may be used in lieu of the
sliding scale. In predicting the distance to the field strength contours, the ef-
40 F.C.C.
FM Broadcast Rules 718
feetive radiated power to be used is that in the horizontal plane in the per-
tinent direction. In predicting other field strengths over areas not in horizontal
plane, the effective radiated power to be used is the power in the direction of
such areas; the appropriate vertical plane radiation pattern must, of course, be
considered in determining this power.
(d) The antenna height to be used with this chart is the height of the radia-
tion center of the antenna above the average terrain along the radial in ques-
tion. In determining the average elevation of the terrain, the elevations between
2 and 10 miles from the antenna site are employed. Profile graphs shall be
drawn for 8 radials beginning at the antenna site and extending 10 miles there-
from. The radials should be drawn for each 45 degrees of azimuth starting with
True North, At least one radial must include the principal community to be
served even though such community may be more than 10 miles from the an-
tenna site. However, in the event none of the evenly spaced radials include the
principal community to be served and one or more such radials are drawn in
addition to the 8 evenly spaced radials, such additional radials shall not be
employed in computing the antenna height above average terrain. Where the
2 to 10 mile portion of a radial extends in whole or in part over a large body
of water or extends over foreign territory but the 50 uv/m contour encompasses
land area within the United States beyond the 10 mile portion of the radial,
the entire 2 to 10 mile portion of the radial shall be included in the computa-
tion of antenna height above average terrain. However, where the 50 uv/m con-
tour does not so encompass United States land area and (1) the entire 2 to 10
mile portion of the radial extends over large bodies of water or forcign terri-
tory, such radial shall be completely omitted from the computation of antenna
height above average terrain, and (2) where a part of the 2 to 10 mile portion
of a radial extends over large bodies of water or over foreign territory, only
that part of the radial extending from the 2 mile sector to the outermost por-
tion of land area within the United States covered by the radial shall be em-
ployed in the computation of antenna height above average terrain. The profile
graph for each radial should be plotted by contour intervais of from 40 to 100
feet and, where the data permits, at least 50 points of elevation (generally uni-
formly spaced) should be used for each radial. In instances of very rugged ter-
rain where the use of contour intervals of 100 feet would result in several
points in a short distance, 200- or 400-foot contour intervals may be used for
such distances. On the other hand, where the terrain is uniform or gently slop-
ing the smallest contour interval indicated on the topographic map should be
used, although only relatively few points may be available. The profile graphs
should indicate the topography accurately for each radial, and the graphs
should be plotted with the distance in miles as the abscissa and the elevation
in feet above mean sea level as the ordinate. The profile graphs should indicate
the source of the topographical data employed. The graph should also show the
elevation of the center of the radiating system. The graph may be plotted either
on rectangular coordinate paper or on special paper which shows the curvature
of the earth. It is not necessary to take the curvature of the earth into consid-
eration in this procedure, as this factor is taken care of in the charts showing
signal strengths. The average elevation of the Smile distance between 2 and 10
miles from the antenna site should then be determined from the profile graph
for each radial. This may be obtained by averaging a large number of equally
spaced points, by using a planimeter, or by obtaining the median elevation
(that exceeded for 50 percent of the distance) in sectors and averaging those
values.
(e) In eases where the terrain in one or more directions from the antenna
site departs widely from the average elevation of the 2 to 10 mile sector, the
prediction method may indicate contour distances that are different from what
may be expected in practice. For example, a mountain ridge may indicate the
practical limit of service although the prediction method may indicate other-
wise, In such cases the prediction method should be followed, but a supple-
mental showing may be made concerning the contour distances as determined
by other means. Such supplemental showing should describe the procedure
employed and should include sample calculations. Maps of predicted coverage
should include both the coverage as predicted by the regular method and as
predicted by a supplemental method. When measurements of area are required,
40 F.C.C.
714 Federal Communications Commission Reports
these should include the area obtained by the regular prediction method ang
the area obtained by the supplemental method. In directions where the ter.
rain is such that negative antenna heights or heights below 100 feet for the 9
to 10 mile sector are obtained, a supplemental showing of expected coverage
must be included together with a description of the method employed in pre.
dicting such coverage. In special cases, the Commission may require additional
information as to terrain and coverage.
$ 3.314 [DELETION]
T. In “FM Technical Standards”, § 3.314 is deleted.
8. In “FM Technical Standards”, $ 3.315 is amended to read as follows:
$ 8.315 TRANSMITTER LOCATION
(a) The transmitter location shall be chosen so that, on the basis of the
effective radiated power and antenna height above average terrain employed, a
minimum field strength of 70 decibels above one microvolt per meter (dbu), or
3.16 microvolts per meter, will be provided over the entire principal com.
munity to be served.
(b) The transmitter location should be as near the center of the proposed
service area as possible consistent with the applicant’s ability to find a sufi.
cient elevation to provide service throughout the area. Location of the antenna
at a point of high elevation is necessary to reduce to a minimum the shadow
effect on propagation due to hills and buildings which may reduce materially
the intensity of the station’s signals in a particular direction. The transmitting
site should be selected consistent with the purpose of the station, ie. whether
it is intended to serve a small city, a metropolitan area, or a large region. In-
asmuch as service may be provided by signals of 1 mv/m or greater field
strengths in metropolitan areas, and inasmuch as signals as low as 50 uv/m
may provide service in rural areas, considerable latitude in the geographical
location of the transmitter is permitted; however, the necessity for a high ele-
vation for the antenna may render this problem difficult. In general, the trans-
mitting antenna of a station should be located at the most central point at the
highest elevation available. In providing the best degree of service to an area,
it is usually preferable to use a high antenna rather than a lower antenna with
increased transmitter power. The location should be chosen that line-of-sight
can be obtained from the antenna over the principal city or cities to be served;
in no event should there be a major obstruction in this path.
(e) The transmitting location should be selected so that the 1 mv/m contour
encompasses the urban population within the area to be served. It is recog-
nized that topography, shape of the desired service area, and population dis-
tribution may make the choice of a transmitter location difficult. In such cases
consideration may be given to the use of a directional antenna system, although
it is generally preferable to choose a site where a nondirectional antenna may
be employed. J ñ
(d) In cases of questionable antenna locations it is desirable to conduet
propagation tests to indicate the field intensity expected in the principal city or
cities to be served and in other areas, particularly where severe shadow prob-
lems may be expected. In considering applications proposing the use of such
locations, the Commission may require site tests to be made. Such tests should
include measurements made in accordance with good engineering practice, and
full data thereon must be supplied to the Commission. The test transmitter
should employ an antenna having a height as close as possible to the proposed
antenna height, using a balloon or other support if necessary and feasible,
Information concerning the authorization of site tests may be obtained from
the Commission upon request. o f
neS Present information is not sufficiently complete to establish “blanket
areas” of FM broadcast stations, which are defined as those areas adjacent to
the transmitters in which the reception of other stations is subject to interfer-
40 F.C.C.
FM Broadcast Rules 715
enee due to the strong signal from the other stations. Where it is found neces-
sary to locate the transmitter in a residential area where blanketing problems
may appear to be excessive, the application must include a showing concern-
jng the availability of other sites. The authorization of station construction in
areas where blanketing problems appear to be excessive will be on the basis
that the applicant will assume full responsibility for the adjustment of the
applicant’s station.
(f) Cognizance must of course be taken regarding the possible hazard of the
proposed antenna structure to aviation and the proximity of the proposed site
to airports and airways. Procedures and standards with respect to the Commis-
sions consideration of proposed antenna structures which will serve as a
guide to persons intending to apply for radio station licenses are contained in
part 17 of this chapter (Construction, Marking, and Lighting of Antenna
Structures). `
9. In “FM Technical Standards”, paragraph (e) of $ 3.816 is amended to read
as follows:
s 8.816 ANTENNA SYSTEMS.
* * * * * H D
(e) Applications proposing the use of directional antenna systems must be
accompanied by the following:
(1) Complete description of the proposed antenna system.
(2) Orientation of array with respect to True North; time phasing of fields
from elements (degrees leading or lagging); space phasing of fields from
elements (in feet and degrees) ; and ratio of fields from elements.
(3) Horizontal and vertical plane radiation patterns showing the free
space field strength in millivolts per meter at 1 mile and effective radiated
power, in dbk, for each direction. The method by which the radiation patterns
were computed or measured shall be fully described, including formulas used,
equipment employed, sample calculations and tabulations of data. Sufficient
vertical plane patterns shall be included to indicate clearly the radiation char-
acteristics of the antenna above and below the horizontal plane.
(4) Name, address, and qualifications of the engineer making the calculations.
10. In “FM Technical Standards”, paragraph (a) (1) of $ 3.317 is amended
to read as follows:
§ 3,317 TRANSMITTERS AND ASSOCIATED EQUIPMENT
(a) Electrical performance standards. * * *
(1) ‘The transmitter shall operate satisfactorily in the operating power
range with a frequency swing of 75 kilocycles per second, which is defined as
100 percent modulation.
11. In “FM Technical Standards”, §3.3833 is amended, Figure 1 is amended,
and Figure 3 is added, as follows:
8 3.333 ENGINEERING CHARTS,
This section consists of the following Figures 1, 2, and 3.
40 F.C.C.
716 Federal Communications Commission Reports
_200 F. 7 8 1000 3 4
i H S EE : : š usa
F(50,50) FM CHANNELS a
:
| oH
|=
5 BE:
? ger
5 E E
š |e Gen E
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EK 3 mër
ES To a F 5
š E
c E I
É < 30 ° Ei Ge
š L ES EH
2 8 30 E iË EI
ë m sori
š H EEN
š z 7 ° s:
2 E 20
š A0
š ei bg z H 3090 ="
°
š i 80 CR a
= D
E a i Gi 10 d
$ L ae i :
š jo A XA so, Ge
š H
š ve CH kel
š 2 eo H
> S
= 40, s =
a 370 gn
10 S
190
200
> TTE DEN i ` a
is = > See r e D0 2000 x + $000
Transmitting Antenna Height in Feet
FM CHANNELS
ESTIMATED FIELD STRENGTH EXCEEDED AT 50 PERCENT OF THE POTENTIAL
RECEIVER LOCATIONS FOR AT LEAST 50 PERCENT OF THE TIME
AT A RECEIVING ANTENNA HEIGHT OF 30 FEET
Foc Š 3.333, FIGURE 1 as amended eff, 9-10-62,
40 F.C.C.
Fleld Strength (E) in Microvoits Per Meter for One Kilowatt Radiated Power
717
FM Broadcast Rules
qp
wyar,
wat NI 3
Ee
Gi
E
ae
toner e
EI
wad T 3A08V ap NI d Š 8 g 8 R 8
wi 3A08V qp NI Hä Š 8
ks
0J1V10YY YIMOd
"EEE'E § fL onpa yyTM ogn qog erpog SuTpITS
40 F.C.
718 Federal Communications Commission Reports
Maximum Power in Kilowatis
Antenna Height Above Average Terrain (Feet:
MAXIMUM POWER
versus I HH
ANTENNA HEIGHT Š ===
t TE
$ fr 1 s: SE
ofa Tey EE i s: H
e -15 -10 -5 ° H 10 pty 20
Maximum Power in db Above One Kllowatt (dbk)
FCC § 3.333, FIGURE 3 as adopted eff. 9-10-62.
40 F.C.C.
FM Broadcast Rules 719
12. In Subpart C of Part 3, “Noncommercial Education FM Broadcast Sta-
tions”, §§ 3.504 and 3.505 are deleted, and new §§ 3.504 and 3.505 are added,
as follows:
8 3.504 ZONES, CLASSES OF STATIONS, USE OF CHANNELS, FACILITIES, AND MINI-
MUM MILEAGE SEPARATIONS BETWEEN STATIONS.
(a) Zones. For the purpose of assignment of noncommercial educational FM
stations, the United States is divided into three zones, Zone I, Zone I-A, and
Zone I, having the boundaries specified in § 3.203.
(b) Classes of stations. Noncommercial educational stations operating on
the channels specified in § 3.501 are divided into four classes, as follows:
(1) A Class D educational station is one operating with no more than 10
waits transmitter power output. Class D stations may be assigned in all zones,
on any of the channels specified in $ 3.501.
(2) Noncommercial educational stations with more than 10 watts trans-
mitter output are classified as Class A, Class B, or Class C, depending on the
effective radiated power and antenna height above average terrain, and the
zone in which the station’s transmitter is located, on the same basis as pro-
yided in $ 3.204 for stations on the non-reserved FM channels. Where a sta-
tion is authorized with more than 3 kilowatts (4.8 dbk) effective radiated
power, or coverage greater than that obtained by the equivalent of 3 kilowatts
effective radiated power and 300 feet antenna height above average terrain, it
js classified as a Class B station if its transmitter is located in Zone I or
Zone I-A, and as a Class C station if its transmitter is located in Zone IT.
Class A stations may be assigned in all zones,
(e) Use of, channels. All classes of noncommercial educational stations may
be assigned to any of the channels set froth in § 3.501.
(d) Facilities.
(1) No minimum effective radiated power or antenna height is specified
for stations operating on the channels specified in § 3.501.
(2) On Channels 218, 219 and 220 specified in § 8.501, no Class B or Class 2
educational station will be authorized with effective radiated power greater
than that specified in § 3.209(b) (1) for the respective class of station, and the
maximum effective radiated power permissible shall also be subject to the pro-
visions of $ 3.209 (b) (2).
(e) Minimum mileage separations. No application for a new station, or
new station, or change in channel or transmitter site or increase in facilities of
an existing station, will be granted unless the proposed facilities will be located
so as to meet the adjacent channel mileage separations specified in $ 3.205(a)
for the class of station involyed with respect to stations on Channels 221, 222,
and 228 listed in §3.201 (except where in the case of an existing station the
proposed facilities fall within the provisions of § 3.205(b)).
(£) Hwisting stations. Stations authorized as of September 10, 1962, which
do not meet the requirements of paragraphs (d) and (e) of this section, may
continue to operate as authorized; but any application to change facilities will
be subject to the provisions of this section.
18. In Subpart C of Part 3 “Noncommercial Educational FM Broadcast Sta-
tions”, § 3.505 is amended to read as follows:
§ 3.505 STANDARDS OF GOOD ENGINEERING PRACTICE.
All noncommercial educational stations operating with more than 10 watts
transmitter output power shall be subject to all of the provisions of the FM
Technical Standards contained in Subpart B of this part. Class D educational
stations shall be subject to the definitions contained in § 3.310 of Subpart B
of this part, and also to those other provisions of the FM Technical Stand-
ards which are specifically made applicable to them by the provisions of this
subpart.
$ 3.551 [DELETION]
14. In Subpart C of Part 3 “Noncommercial Educational FM Broadcast Sta-
tions”, § 3.551 is deleted.
40 F.C.C.