Document text
152 Federal Communications Commission Reports
Channel Assignment
FM Stations, Class A, B, C
Frequency Assignment
Station Separation
Table of Assignments
Final rule making order adopted to permit the operation of an
increased number of FM broadcast stations. Rule changes were
needed to meet the demand for FM broadcast service that could
not be satisfied under the present rules. New rules allow Class A
stations to operate on all channels, authorize three new classes of
stations, and reclassify existing stations, after a period of three
years, according to their operating facilities.
-FM Broadcast Stations
BC Docket No. 80-90
FCC 83-259
BEFORE THE
FEDERAL COMMUNICATIONS COMMISSION
WASHINGTON, D.C. 20554
In the Matter of
Modification of FM Broadcast Station BC Docket No.
Rules to Increase the Availability of Com- 0-90
mercial FM Broadcast Assignments. RM-2587
RM-3226
RM-3367
REPORT AND ORDER
(PROCEEDING TERMINATED)
(Adopted: May 26, 1983; Released: June 14, 1983)
By THE COMMISSION: COMMISSIONER QUELLO DISSENTING AND
ISSUING A STATEMENT; COMMISSIONER
FOGARTY NOT PARTICIPATING; COMMISSIONER
RIVERA ISSUING A SEPARATE STATEMENT;
COMMISSIONER SHARP ABSENT.
INTRODUCTION
1. The Commission’s Notice of Proposed Rule Making (“Notice”)
in this proceeding suggested a number of rule changes to increase
the availability of FM stations within the present assignment
structure.!
1 78 FCC 2d 1235; 45 Fed. Reg. 17602; adopted February 28, 1980.
94 F.C.C. 2d
FM Broadcast Stations 153
2. The FM band extends from 88-108 MHz and is divided into
100 channels numbered from 201 to 300. The lower 4 MHz contains
Channels 201 to 220 and is reserved for noncommercial educational
stations. The upper 80 channels between 92 MHz and 108 MHz may
be used by both commercial and noncommercial stations. The use of
these channels is governed by the FM Table of Assignments
(“Table”) found in Section 73.202(b) of the Commission’s Rules. It
provides a listing of communities in which stations are operating, or
may operate, and the channel on which they must transmit.
3. When a new station is desired, the Table must be amended
through a rule making proceeding to add the requested community
and channel. The proposed station must be located a sufficient
distance from pertinent co-channel and adjacent channel stations
and still be capable of providing a strong signal over the desired
community. The distance separation requirements are based upon
the assumption that each station is currently, or at some future time
will be, operating with maximum facilities (effective radiated power,
“ERP,” and antenna height above average terrain, “HAAT”). Thus,
the Table permits stations to begin operating with less than
maximum facilities and to increase them as their financial situations
improve.
4. The Commission authorizes three classes of FM stations. Class
A stations operate only on 20 designated channels and have a service
radius of 15 miles. The service radius is determined from the co-
channel distance separation requirements, which provide protection
from interference to approximately the station's 1 mV/m contour.
Class B or C stations operate on the remaining 60 channels. Whether
a station is designated Class B or Class C depends upon its
geographic location. Class B stations are assigned in the more
densely populated parts of the nation and have a service radius of 40
miles, representing protection of their 0.5 mV/m contour. Areas
where Class B stations may be located are designated Zones I and I-
A. Class C stations are assigned elsewhere (Zone II) and have a
service radius of 57 miles, representing protection of their 1 mV/m
contour. :
5. The Notice recognized that under the present allotment rules,
additional service canhot be offered to many parts of the nation
where demand has not been satisfied. Commission studies identified
three existing standards that appeared to limit new FM service:
(a) Class A stations may operate only on 20 designated channels, thereby
foreclosing substantial areas from using the 60 Class B/C channels for these
. smaller stations;
(b) the distance separation requirements assume stations are operating with
maximum permissible facilities, although 80% of the Class C stations and 35% of
all FM stations were not operating. with maximum, or near maximum, facilities at
the time the Notice was adopted; and
(c) the Class B separations, which reflect protection of the 0.5 mV/m field strength
94 FCC. 2d
154 Federal Communications Commission Reports
contour rather than the 1 mV/m contour, prohibit many communities from
obtaining additional FM allotments.
6. Based on these findings, the Commission proposed to respond
to the continuing demand for FM assignments by:
(a) allowing stations with Class A facilities to operate on the 60 Class B/C channels
if a Class A channel was not available; a
(b) increasing the number of classes allowed from three to five by adding Class B1
(operating facilities between Classes A and B) and Class C1 (operating facilities
between Classes B and C) stations, so protection would more closely approximate
Service area;
(c) permitting Class B stations to operate in the same areas as Class C stations
(Zone ID);
(d) adopting a new distance separation table based on providing uniform protection
to the 1 mV/m (60 dBu) contour of all stations (the primary impact of the adoption
of this proposal would be on Class B stations whose separations are now based on
the 0.5 mV/m contour);
(e) requiring existing Class B and Class C stations operating with less than
maximum, or near maximum, facilities to reach the minimum power and antenna
height specified for the new classification system within three years, or be
reclassified based on their actual operating facilities; and
(f) allowing new Class C stations six years to reach their minimum power and
antenna height requirements because they would be the only class of station to
have a minimum antenna height requirement.”
7. Central to the Notice’s proposals was the retention of the basic
Table of Assignments framework. It did not propose to modify the
allotment structure represented by the Table. Instead, the Commis-
sion sought to focus on those changes that could achieve immediate
benefits and to defer consideration of more complex proposals until a
later date. These included such matters as terrain shielding,
directional antennas, etc.
8. Those parties that submitted comments and reply comments
that relate directly to our discussions are listed in Appendix A.*
Seven months after the close of the reply comment. period, the
National Radio Systems Committee (“NRSC”) submitted new FM
receiver measurement data.* On August 3, 1982, the Commission re-
opened the record to accept the NRSC report and two others filed by
2 The Commission also proposed to adopt the International System of Units
(commonly termed the metric system) for the FM broadcast service because it was
considering modifying many of the technical rules.
The National Radio Systems Committee is co-sponsored by the EIA and the NAB
and “is comprised of persons from the broadcasting and electronics manufacturing
industries and others interested in improving the overall technical quality of radio
broadcasting and reception. The NRSC by its charter does not assume a position of
advocacy on any matter before the Federal Communications Commission or any
other governmental body. One function, however, is to provide agencies with
information on transmitting and receiving technology which may be used in
rulemaking proceedings.”
[Committee description taken from the comments of the NRSC; October 16, 1981.]
94 F.C.C. 2d
FM Broadcast Stations 155
the Advisory Committee on Radio Broadcasting (“Advisory Commit-
tee”).* In addition to accepting the reports, the Commission allowed
30 days for other parties to comment on these late-filed studies,*
9. Subsequently, the Advisory Committee submitted additional
reports and again requested that the Commission re-open the record
to accept them and to request comments on their findings.* The
Commission declined the Committee’s request stating that it would
consider the reports to be ex parte comments submitted under the
guidelines governing non-restricted proceedings. Thus, the Commis-
sion could consider these reports in its deliberations and any other
comments submitted in response to the filing of the reports could
also be considered to be ex parte comments.
Summary of Actions Taken
10. The Commission has reviewed each of the comments filed.
Based on that review, we have decided to amend the rules in the
following manner:
(a) Class A stations will be allowed on Class B/C channels;
(b) the distance separation requirements will not be modified for existing station
classes to reflect uniform protection to the 1.0 mV/m contour (thus, separations for
Class B stations in Zones I and I-A still will be based on the 0.5 mV/m contour
rather than the 1.0 mV/m proposed);
(c) one new class of station, Class B1, with an expected service range of 45
kilometers (28 miles), will be allowed to operate in Zones land I-A;
(d) two new classes of stations, Classes Ci and C2, with expected service ranges of
>
The Commission acted in response to a petition from the Advisory Committee.
This committee evolved from the “Advisory Committee on AM Broadcasting in
Region 2.” The latter committee was established to advise the staff of the
Commission during its preparation for, and participation in, the International
Telecommunications Union Regional Administrative Conference on AM Broad-
casting in the Western Hemisphere. The purview of the AM conference committee
was expanded to include FM broadcast issues when its charter was amended on
September 10, 1980. It was renamed the “Advisory Committee on Radio
Broadcasting” and its organization was altered to specify two subgroups within the
committee. One subgroup was to address technical matters while the other
concentrated on spectrum allocation matters. [See the Memorandum Opinion and
Order issued by the Commission on September 22, 1980 (FCC 80-537).]
The studies are entitled: (1) Report to the National Radio Systems Committee from
the FM Subcommittee Task Force, July 24, 1981 (“NRSC Report”); (2) FM
Broadcasting Receiver Characteristics and Protection Criteria, J uly 7, 1982,
(“Technical Subgroup Report”); and (3) Report on FM Allocation Policies, July 9,
1982 (“Allocations Subgroup Report”). .
The «studies submitted by the Advisory Committee are entitled: Subjective
Evaluations of Audio Degraded by Noise and Undesired FM Signals (“Subjective
Audio Study”), November 17, 1982; A Study of FM Station Mileage Separations
(“Mileage Separations Study”), November 17, 1982; Potential Effects of BC Docket
No. 80-90 on FM SCA Operations (“SCA Study”), November, 1982; and A Study of
Stereo Radio Listening (“Stereo Listening Study”), December 7, 1982.
a
o
94 F.C.C. 2d
156 Federal Communications Commission Reports
72 kilometers (45 miles) and 52 kilometers (32 miles), respectively, will be allowed
to operate in Zone IT;
(e) existing stations will be required to meet minimum facility requirements within
three years or be reclassified to a station class based on the new classifications. For
Class C stations, a minimum antenna height requirement of 300 meters (984 feet)
HAAT will be adopted;
(f) new Class C stations will be required immediately to meet minimum facilities
rather than being provided six years within which to comply; and
(g) the rules contained in the FM service will be converted to the International
(metric) System of Units.
These amendments are intended to provide for additional FM
stations in many parts of the country and still permit existing
stations to provide service equivalent to that embodied in the present
allotment rules. They represent, in our best judgment, the optimum
rule changes necessary to allow new stations while preserving the
unique qualities of the FM service.
ANALYSIS OF THE RECORD
11. Our analysis of the record in this proceeding first will set
forth those comments that relate generally to the legal and policy
issues presented in the Notice. After a summary and discussion of
those comments, we will proceed to a recitation and analysis of those
comments that addressed general technical issues. Then the record
on each specific proposal set forth in the Notice will be summarized
and discussed. Finally, we will discuss various matters that are
ancillary to the adoption of the changes set forth in paragraph 10,
supra, including the implementation of those changes.
Legal and Policy Matters
12. A number of parties argued that sufficient information was
not available, nor sufficient thought given, for the proposals in the
Notice to be satisfactorily considered. ABC, NAB, and other parties
urged the Commission to develop a master plan for an integrated
AM and FM aural broadcast service before seriously considering any
deviations from the existing service structures. They claimed the
current approach of instituting separate proceedings for each service
represented a conviction to create new radio outlets without regard
to public service costs. Cox and Multimedia supplied detailed
historical perspectives of the development of the FM service. Noting
FM’s complementary nature to the AM service, they argued that the
suggested modifications be considered in an omnibus proceeding.
13. ABC also argued that the instant proceeding is an ineffective
mechanism for dealing with important issues such as demand,
economic viability, appropriate service area size, assignment priori-
ties, and viable alternatives. The Advisory Committee urged the
Commission to make more extensive economic studies of FM stations
94 F.C.C. 2d
FM Broadcast Stations 157
before taking final action. Its reports to the Commission, along with
comments submitted by NBC and ABC, cited economic losses and
small profit margins as indications that further competition would
be undesirable in many situations. PAB and NRBA claimed that
additional outlets in marginally profitable markets would result in
less local news and public affairs programming. ABC pointed out
that, according to several court decisions, the Commission is
expected to assess the merits of adding new broadcast stations by
balancing public service gains against losses.
14. Some parties argued that demand by potential broadcasters
does not represent a public interest determination as required by the
Communications Act. Still others claimed that adoption of the
proposals in the Notice would violate Section 307(b) of the Communi-
cations Act, which requires a “fair, efficient and equitable distribu-
tion of radio services.” They suggested that these factors only can be
fully examined if the Commission issues a Notice of Inquiry into
these subjects before proposing specifics in a Notice of Proposed Rule
Making. š
15. NBC contended that the current FM service is efficient and
diverse. Quoting from the Spring 1980 Arbitron data, it stated that of
the top 100 markets containing 71% of the population over 12 years
of age, 88 markets contain 5 or more FM stations; and of the top 150
markets containing 77% of the population over 12 years of age, 123
markets contain 5 or more FM stations. A study performed by A.D.
Ring € Associates (“A.D. Ring”) was submitted to support the
proposition that the proposals would not increase availability in
larger markets. The study investigated potential FM stations under
the proposed changes for 24 of the top 100 markets. It indicated that
no additional FM stations were possible in any of the top 12 markets
and only one was found in the top 15 markets. Of the 9 remaining
markets studied (markets 16 to 96 at ten market intervals), it
indicated that the proposed changes would result in no Class C or C1
stations, 4 Class B stations to 3 communities, 19 Class B1 stations to
7 communities, or 34 Class A stations to all 9 communities.” Because
no additions would be possible in the highest demand markets (e.,
the top 12), several parties claimed that the proposed changes served
no useful purpose.
16. After reviewing the comments submitted in this proceeding,
we believe that no more appropriate forum exists within which to
comprehensively examine the public interest need for additional FM
radio service and the rule changes necessary to bring it about. Every
effort has been made to establish as complete a record as possible
and to encourage widespread public and industry involvement. We
expanded the purview of the Advisory Committee to include the FM
7 Presumably, some combination of Classes A, Bl, and B stations is possible in most
of the communities. However, this is unclear from the data submitted.
94 F.C.C. 2d
158 Federal Communications Commission Reports
service, extensively delayed this proceeding by extending the com-
ment period several times, and even accepted late-filed comments.
The Commission believes the record before us is adequate to explore
all pertinent issues. All matters addressed by the commenting
parties (including those studies concerning new receiver characteris-
tics, average distance separations, and audio listener tests and
surveys) have been fully examined and factored into our decision.
The need for additional outlets and the rule changes necessary to
accommodate them have been carefully weighed against the effects
such changes would have on the present FM service. We have
concluded that the public interest is best served by adopting most of
the rule changes proposed. There exists no reason to investigate
further the desirability of modifying the rules, as many parties
suggested, because such an investigation would only re-confirm what
the record before us already indicates and would needlessly delay the
benefits of additional FM station availability. Moreover, as subse-
quent discussion indicates, we have been keenly aware of the
interrelationships of the AM and FM services in satisfying our
statutory mandate to
make such distributions of licenses, frequencies, hours of operation, and power
among the several States and communities as to provide a fair, efficient, and
equitable distribution of radio service to each of the same.*
17. When assigning radio broadcast stations, the Commission’s
basic objectives have been to provide
~ at least one service to everyone,
- diversified service to as many persons as possible, and
- outlets for local expression addressing each community’s needs and interests.’
We recognize that these goals can be self-contradictory; therefore it
is necessary to strike compromises that both foster service to all and
provide for outlets for local expression in as many communities as
possible. Such compromises have been struck in the past, resulting in
radio service in the United States to 98% of the population with at
least one primary fulltime aural service (.e., one primary nighttime
AM or one FM signal of 1 mV/m field strength or greater). Further
Notice of Proposed Rule Making, Docket No. 20642, at paragraph 53.
The rule changes adopted herein will foster the same goals,
® Section 307(b) of the Communications Act of 1934, as amended; 47 U.S.C. $307(b).
8 The Commission recently simplified its FM allotment priorities and reaffirmed
these goals for this broadcast service. New FM channels are to be allotted: first,
where they will provide a first fulltime aural service; second, where they will
provide a second fulltime aural service or a first local service; and third, where
they are necessary to meet other public interest matters. (See the Report and
Order in BC Docket No. 80-130, reconsideration pending, adopted on May 20,
1982.) Those comments seeking a re-examination of the FM priorities have been.
satisfied by Commission action in BC Docket No. 80-130.
94 F.C.C. 2d
FM Broadcast Stations 159
providing opportunities for new local outlets while preserving
existing primary service areas.
18. Some of the comments stated that demand for assignments
does not represent the necessary Commission finding that such
assignments are “in the public interest.” Demand, however, does
represent an applicant’s judgement of a community’s interest in and
potential financial backing for a new station. We regard this as a fair
basis on which to examine the public interest aspects of new
proposals. As a practical matter, if a community really has litile
potential! for establishing an additional station, we believe it unlikely
that applicants or investors would be willing to extend the effort or
financial backing that is required. As a second matter, potential
competition should not be curtailed by the Commission second
guessing a market’s potential. Other comments claimed that in-
creased competition could result in disservice to the public by
reducing existing programming services. Our experience is that the
public generally benefits from program diversity brought about by
increased competition. In an individual situation, however, based on
an application and appropriate pleadings, the Commission may be
called upon to evaluate the overall adverse impact on service that
could result from the institution of a new service in a community.
See, e.g., Carroll Broadcasting v. FCC, 258 F.2d 440 (D.C. Cir. 1958).
19, We also believe there is ample evidence to support the need
for more FM stations. The Station Requirement List, submitted to
the Region 2 Conference on AM Broadcasting, represents approxi-
mately 3,000 separate locations where the Commission foresaw a
potential need or demand for nearly 4,000 additional radio stations
in the immediate future.'” The importance of the list for this
10 The Commission notified this list to the International Frequency Registration
Board (IFRB) to insure international protection of our future radio needs. The list
of potential station requirements for various countries in the Western Hemi-
sphere was submitted to the Second Session of the Administrative Conference on
AM Broadcasting in Region 2 held in November and December, 1981, to establish
future planning needs. Although time did not allow adoption of all these
requirements, provisions were made for adding them after the conference. (See
List of Requirements Concerning Stations to be Authorized between 1 January
1983 and 31 December 1987; Appendix to Document No. 19-E, 16 October 1981.)
This inventory of potential interest or demand for additional fulltime radio stations
was compiled from lists of:
a) locations of all daytime-only AM stations;
b) cities asserted as needing minority-owned or public radio stations as defined by
National Black Media Coalition and National Public Radio in the Report on New
Station Demand and Viability as submitted by the Advisory Committee on
December 17, 1980;
©) a few places where declarations of interest were filed in response to BC Docket
No. 79-164 (the 9 kHz proceeding); and
94 F.C.C, 2d
160 Federal Communications Commission Reports
proceeding is not the specific communities noted but the magnitude
of the communities identified as being underserved. More than half
of these assignments are in communities with no local AM or FM
assignments, no local nighttime service, or are for additional
minority-owned or local public radio stations. The Commission’s
studies have shown that additional AM stations possible as a result
of our clear channel actions could only satisfy about 125 of these
needs.
20. The A.D. Ring study on the availability of new allotments
assumed that demand for new assignments exists only in the larger
communities already having assignments. Nowhere in the Notice did
we imply that the top 100 markets (sampled by A.D. Ring) represent
the most serious cases of need. In this regard, the Commission
undertook an extensive computer analysis of 200 entries from the
Station Requirements List that had no local radio outlets, contained
only daytime AM stations, or were asserted as needing additional
minority-owned or public radio stations. Our study found that the
existing FM allotment rules would allow a total of 57 new stations at
15 of 200 locations studied (see Table I of Appendix B). In other
words, 7% of the locations studied could have at least one new FM
outlet under the existing rules. For the various proposals under
consideration, the studies indicated that the availability of at least
one new outlet per location ranged from 41% to 61% of the study
locations depending on which modifications are adopted. Thus, the
potential of each of the Commission’s individual proposals to satisfy
the need for additional FM stations can readily be seen.'*
21. To determine if these results were indicative of availability
at a larger number of communities, the Commission conducted
another examination using 1000 entries. This study indicated that
our earlier findings were conservative. It also showed that under the
rules being adopted, additions could be made to approximately: 49%
of the communities studied that have daytime AM stations only;
31% of the communities studied that have no local assignments;
40% of the communities studied that were asserted as requiring
additional minority-owned stations; and 26% of the communities
studied that were asserted as requiring additional public radio
d) communities of at least 2,500 persons which have no local AM or FM
assignments and are located more than 10 miles from cities of at least 25,000
persons (compiled by the staff).
The Commission has made extensive use of this list for international negotiations as
well as to evaluate AM service availability for the 9 kHz proceeding.
11 For convenience, a summary of the studies and number of additions possible for
each alternative is listed in Appendix B. Further explanation of these studies,
their definition and limitations, can be found in a report entitled “Computer
Project for BC Docket No. 80-90 (Increased FM Availability)”, May 13, 1982, that
has been placed in the docket file.
94 F.C.C. 2d
FM Broadcast Stations 161
assignments that cannot be accommodated in the reserved portion of
the FM band (82-92 MHz).'*
22. Other indications of unsatisfied demand for additional FM
service may be found in the comments of more than 35 parties who
supported the proposals in this proceeding. Although the Notice
specifically requested that commenters not submit requests for new
FM allotments, approximately half indicated that additional FM
stations needed in their communities were not available without the
changes proposed. We also note that we receive approximately 200
petitions annually to amend the FM Table of Assignments, and that
approximately 60% of the new assignments have two or more
competing applications submitted.
23. In sum, we are persuaded that there exists a substantial
demand for new FM service that cannot be satisfied under existing
rules. We are persuaded further that the rule changes adopted
herein provide the most efficacious means of accommodating that
demand.
Technical Matters
24. Technical oppositions to the proposals in the Notice generally
alleged that few stations operate with maximum facilities at
minimum spacing. Therefore, stations are covering larger.areas with
a higher quality service than would be expected under the present
rules.
25. The proposals contained in the Notice were, with one
exception, based on the same technical assumptions as the allotment
and assignment rules adopted in 1963. These rules consider interfer-
ence protection to be determined solely by the separation, power, and
antenna height limitations. They do not recognize concepts such as
protected and interfering contours for individual stations. The
distance separations provide protection from co-channel and first
adjacent channel interference within a “primary” service range.'*
12 The difference in availability between the existing rules and the modifications
adopted herein is shown in * Appendix B, Figures 1 and 2. These figures show the
approximate distribution of additions for 1000 study locations throughout the
contiguous United States. Every asterisk or star on Figure 1 indicates an
approximate location (with respect to referenced communities) where an addi-
tional FM station may be added under the existing rules. Figure 2 indicates the
possible station locations under the new rules adopted today, assuming all
existing stations elect to increase facilities to avoid being reclassified.
13 When originally adopted in 1963, the minimum separations were based on the
existing FM propagation curves. These curves are not expected to predict service
or interference at any particular location at any one time, However, they are
useful for predicting service on a large area basis and therefore are used to
analyze general assignment questions. Thus, the predicted service area of a class
of station is indicated by the propagation curves for the generalized situation and
may, or may not, reflect the actual service provided by a given station. For this
reason, the rules state that the only protection to which a station is entitled is
94 F.C.C. 2d
162 Federal Communications Commission Reports
At that time, the Commission decided that service ranges of 15 miles
for Class A stations, 40 miles for Class B stations, and 65 miles for
Class C stations would provide reasonably adequate service areas
while permitting a sufficient number of FM assignments to be
made.'* Assuming that stations operate with maximum facilities,
the minimum co-channel separations yielded protection of the 0.927
mV/m contour for Class A, 0.562 mV/m for Class B, and 0.944
mV/m for Class C stations. The Notice proposed separations that
would have protected the 1.0 mV/m contour for all classes of
stations; in other words it retained the approximate service areas of
the Class A and Class C stations but reduced it for Class B stations.
26. In response, the comments claimed service far beyond these
contours and noted that the present FM allotment rules result in an
interference-limited service. That is, the predicted interference-free
service areas are generally greater than those anticipated by the
minimum separation requirements because few, if any, stations are
limited in every direction by co-channel and adjacent channel
stations operating with maximum facilities at minimum spacings.
Several parties claimed that a signal at the 0.05 mV/m (34 dBu) level
may be received. ABC noted that calculations provided by A.D. Ring
indicated that a field strength of 0.063 mV/m (36 dBu) will permit
satisfactory stereophonic service (in the absence of interference)
while good monophonic reception is possible with a field strength of
only 0.0056 mV/m (15 dBu). Still other parties noted that the CCIR,
the International Radio Consultative Committee, recommends .25
mV/m (48 dBu) for general planning purposes.
27. Metromedia, Cox, Multimedia, and NBC submitted detailed
showings of what they considered the interference-free service
contours of their stations. ABC stated that an examination of their 7
owned and operated stations revealed that their existing interfer-
ence-free service areas were greater than the area recognized by the
minimum distance requirements. Metromedia submitted studies
claiming the interference-free service offered by three of its stations
would be reduced by 28, 37, and 43% of their geographic service
areas if the proposals suggested in the Notice were adopted. Similar
NBC studies indicated population losses for its stations of between
4.8 and 33% if their interference-free service areas were restricted
by the proposals. It further noted that those losing service would not
have it replaced by the new stations. NBC claimed that locations
between 33 and 60 miles from New York City would lose most, if not
that provided by the distance separation requirements, not the predicted service
area indicated by the propagation curves (see Section 73.209 of the Rules). We are
not changing this concept in this proceeding.
14 The propagation curves in use in 1963 predicted a 65 mile service range for Class
C stations. Those curves were refined in 1975 (53 FCC 2d 855), and the new curves
indicate that the 180 mile co-channel separation figure yields a 57 mile service
range as indicated at paragraph 4, supra.
94 F.C.C. 2d
FM Broadcast Stations 163
all, of the New York City service. Thus, it concluded, the suburban
and rural populations surrounding the larger cities would suffer the
greatest losses. Cox and Multimedia also claimed that the only
practical way of serving many suburban areas is with wide-area
metropolitan stations.
28. Another A.D. Ring study submitted by ABC claimed a net
loss in service would result from the Commission’s proposals. It
contained several theoretical assignment situations where new
stations were interjected into certain currently permitted station
groupings. All additions resulted in a net loss of service area.'* It
claimed this proved that any increases in FM availability would be to
the detriment of present listening audiences.
29. NTIA, in reply, argued that stations should only be protected
to “a primary service area” and service beyond that limit is properly
considered secondary or unprotected. It also argued that the A.D.
Ring study did not consider several factors, including the use of
directional receiving antennas in rural areas (which would reduce
the level of the interfering signal), the capture effect of FM receivers
to distinguish the desired signal from the weaker undesired co-
channel signal (which would reduce the large areas of degraded
audio quality)'*, and the population densities in the interference
zone (which should be much smaller than those near new community
outlets).
30. Upon review of these comments, we note that the Commis-
sion recognized in 1963 that certain amounts of potential interfer-
ence-free service had to be discounted if a sufficient number of
assignments were to be made. Thus, we adopted mileage separations
which struck a balance between the size of a station’s contemplated
service area and the number of stations that could be authorized
throughout the country. Our experience since then has indicated
that the balance was not incorrectly determined. From 1,100
commercial FM stations in 1963, we now have 3,800, and the demand
for new FM stations is evident by the number of new channel
15 The evaluations indicated a net loss in service area of:
(a) 2,075 square miles if a Class B station were located at the center of 4 Class B
stations located at the four corners of a square 170 miles on a side;
(b) 563 square miles if a Class B1 station were located at the center of 4 Class B
stations located at the four corners of a square 153 miles on a side;
(c) 1,695 square miles if a Class B station were located at the tip of a triangle 120
miles from 2 Class B stations that are 170 miles from each other; and,
(d) 2,649 square miles if a Class B1 station were located at the tip of a triangle 108
miles from 2 Class B stations that are 153 miles from each other.
Reception of one of two co-channel FM signals of nearly equal strengths is
possible because FM receivers are capable of responding to the stronger of the two
signals. AM receivers provide mixed reception in these cases.
1
94 F.CC. 2d
164 Federal Communications Commission Reports
allotments requested every year and the instances of competing
applications for available channels.
31. We recognize that the introduction of new stations into the
current scheme could cause interference to the reception of existing
stations beyond their normally contemplated service areas. Indeed,
this is the case under present rules where the Commission regularly
receives letters complaining of lost FM service (outside the primary
service area) when a new station is activated or an existing station
modifies its facilties. Proposed rule changes that would permit
additional new stations would similarly create losses of secondary
services. The opponents of the rule changes, however, have failed to
provide any information that the populations allegedly losing such
extended services exceed the population gains from new stations.!7
We believe that these losses are more than compensated for by the
provision of new services, particularly to communities without local
service. In this regard, we note that 98% of the population of the
United States currently receives at least one fulltime primary aural
service. The new stations contemplated herein would not adversely
affect that primary service, but they would provide local service (or
local fulltime service) to communities that are precluded under
current rules. In this manner, the percentage of the population
enjoying primary aural service and the number of communities with
local stations may be increased. On balance, therefore, we believe
that the provision of new primary service and first and/or second
local service is a higher priority than the preservation of service
beyond the normally protected service area of existing stations. This
is particularly the case where that extended service may be
adversely affected under current rules if: the providing station
changes its location; a limiting station is authorized under current
distance separation requirements; or an existing limiting station
changes or increases its facilities within current restrictions. Accord-
ingly, we do not believe it appropriate to protect these extended
service areas at the expense of new primary service.
32. Some commenters also alleged that the present minimum
separation requirements result in a low quality signal at the outer
edge of a station’s primary service range. They noted that while the
original protection ratios are satisfactory for regular FM broadcast
operations, they are unable to protect multiplexed operations
17 The previously referenced theoretical A. D. Ring study is limited to areas of
alleged loss of service only. It, therefore, could not provide information on the
population within those areas, the population that would receive primary service
from the presumed new station, or the other services available in the asserted
“loss” area. The interference-free service areas that Cox and Multimedia claimed
for their stations, however, each contain between 17 and 34 FM stations located
either within or directly along the claimed service contours of each station.
Between 7 and 14 of these locally assigned FM stations are located within the
areas they claim will lose service (except for Station WAIA, Miami, Florida,
where the interference-free service is mostly over swamp land).
94 F.C.C, 2d
FM Broadcast Stations 165
(stereophonic broadcasting and subsidiary communications opera-
tions). The comments urged sufficient protection of the service
contour to permit “satisfactory” reception of these operations at the
full extent of their service range.
33. In support of this argument, these comments called attention
to the international standard for stereophonic reception which is
based on a 50 dB audio frequency (“AF”) signal to noise (“S/N”)
ratio. (The international standard is contained in the recommenda-
tions of the CCIR.) To provide for this level of quality, they argued
that the distance separation requirements should be increased to
provide higher radio frequency (“RF”) desired to undesired (“D/U”)
signal protection ratios.** The Technical Subgroup Report summa-
rized several recent studies and submitted curves indicating the
effect of various distance separations on co-channel protection ratios
for a desired 1 mV/m (60 dBu) signal.*? This report and several
comments noted that the NRSC Report concluded that reception of a
signal yielding a 50 dB AF S/N ratio in the stereophonic mode
requires RF D/U protection ratios of 40 dB for co-channel, 25 dB for
first adjacent channel, and -20 dB for second adjacent channel
stations.
34. Also, Group W alleged that FM subcarrier services could not
be provided effectively if stations operated at minimum separation
distances. They stated that any modifications which would decrease
current protection could significantly reduce the quality of subcarri-
er services. The SCA Study, submitted by the Advisory Committee,
echoed this argument and noted that further investigations should
be performed.
35. Although the Commission was aware of the fact that some
FM stations were providing stereo service in 1963 when it first
addressed this issue in Docket No. 14185, and that such service
required greater protection for high quality reception, it did not
select separations to protect stereo service to the limit of the
18 The Advisory Committee, urging protection of stereophonic service, submitted
three studies dealing with this topic: the Stereo Listening Study; the Subjective
Audio Study; and the Mileage Separations Study. These studies indicated that (1)
approximately one-half of all radio receivers are capable of stereophonic
reception, with stereophonic listening about twice as common as monophonic
listening; (2) a 50 dB AF S/N ratio was necessary for satisfactory stereophonic
reception (if the presence of the interfering signal was to be only “slightly
annoying” according to a panel of expert listerners); and (3) the average co-
channel separation between stations yields a 34 to 40 dB RF D/U signal
protection ratio.
The reports concerning protection standards are: Report to the National Radio
Systems Committee from the FM Subcommittee Task Force, July 24, 1981; Report
of the National Quadraphonic Radio Committee to the Federal Communications
Commission, November 1975; Recommendations and Reports of the CCIR, 1978;
and A Study into Current FM Receiver Performance and the Relevance of FM
Allocation Criteria, Peter Cahn and Associates, April 1978.
1
94 F.C.C. 2d
166 Federal Communications Commission Reports
otherwise contemplated service radius. The requests to increase
protection ratios were rejected based on the need to provide for a
sufficient number of necessary assignments and because stereophon-
ic broadcasts were considered to be an optional enhancement of a
station’s entertainment programming.
36. Nonetheless, the Commission re-examined the desirability of
requiring such protection in response to the comments received in
this proceeding. We used the NRSC receiver data to determine the
expected service ranges under the present rules for monophonic and
stereophonic reception of signals having different qualities. A 30 dB
AF S/N ratio was used to represent the “standard quality” mono-
phonic service now provided by the separation requirements. (This
figure generally is assumed to form the basis for present protection
ratios although, in Docket No. 14185, the Commission did not
acknowledge it as such.) A 50 dB AF S/N ratio was used to represent
the “high quality” stereophonic service referenced by the comments.
We developed the following table based on a receiver having the
performance characteristics obtained by averaging the data con-
tained in the NRSC report (assuming co-channel stations operating
at minimum distance separations with maximum facilities):
Predicted Primary
Type of AF S/N RF D/U Service Area (miles)
Reception Ratios Ratios Class A Class B Class C
mono 30 dB 14 dB 19.4 47.5 63.5
stereo 30 *20 16.6 415 57.1
mono 50 35 7.9 27.1 41.3
stereo 50 40 6.2 22.6 36.1
*RF D/U ratio used to determine present co-channel separation distances.
Thus, the present co-channel Class C separation requirement of 180
miles permits “standard quality” monophonic reception at a distance
of approximately 63 miles while “high quality” stereophonic recep-
tion is expected to a range of 36 miles. All minimum separations
provide for an “inner ring” of high quality stereophonic service
which gradually diminishes to standard quality monophonic service
at the limit of the primary service range in the direction of the
undesired station.
37. To provide stations with the 40 dB RF D/U protection
necessary to achieve a 50 dB AF S/N ratio, however, would require
the separation between co-channel Class C stations to be increased
from 180 miles to 255 miles. Such an increase amounts to a Class C
station’s signal experiencing 20 dB RF D/U protection at a distance
of 82 miles from the transmitter rather than 57 miles as currently
expected. In other words, protection that results in 50 dB AF S/N
stereophonic service simply extends a station’s monophonic service
range. If the new distance separations were the only ones based on
the higher protection levels, the new station classes would require
distances as great, or almost as great, as the present requirements
94 FCC, 2d
FM Broadcast Stations 167
for the larger classes. For example, for a new Class C1 station to offer
a minimal 34 dB RF protection level, it would have to be located at
least 217 miles from an existing co-channel Class C station (while a
new Class C would only have to be separated from an existing Class
C station by 180 miles), Analysis of the adjacent channels yields
analogous results.
38. To require protection at such levels would effectively pre-
clude many new assignments. Even if this proceeding were broad
enough to determine a minumum level for predicted stereo service,
we do not believe that protection of that service beyond what was
contemplated in 1963 would be appropriate. As we found 20 years
ago, such protection would significantly increase the necessary
separation between relevant channels and thereby substantially
decrease the potential for new stations. We believe that the balance
as originally struck provides adequate service areas to potentially
support a station’s operation while giving opportunities to create
enough stations to provide a fair, equitable, and efficient distribution
of radio service among the several States and communities. See 47
USC 307(b) (1936)
39. We recognize that permitting Class A stations on Class B/C
channels and the intermediate classes of stations provide additional
opportunities for the creation of stations that may have a limiting
effect on the stereo service areas enjoyed by existing stations by
virtue of their location at distances exceeding the minimums
established in the rules. However, we believe that the potential gains
of new service, consistent with the mandate of Section 307(b), far
outweigh the losses of enhanced (stereophonic) service predicted by
the commenting parties since protection was not afforded the
affected areas under the existing rules. In making this judgment, we
emphasize that such areas will continue to get the same protection
for monaural service as was originally comtemplated in 1963. That is
to say, the balance is between new service and enhanced (stereophon-
ic) service, and we find no compelling reason to increase previously
granted protections at the expense of needed new service to
communities that would otherwise be precluded from getting a new
FM service.
40. In this regard, we again emphasize that the communities we
have identified as potential locations for new FM assignments under
these rules include a substantial percentage of places with no local
service or with only daytime AM service where existing rules would
not permit a new FM station. We believe that provision of such
service outweighs a predicted loss of multiplex services that may
already be severely curtailed by existing co- and adjacent channel
stations.
41. The requests to increase the protection ratios on which the
separations are based are directly related to the arguments concern-
ing service beyond the theoretical protected contour. Parties have
94 F.C.C. 2d
168 Federal Communications Commission Reports
argued that we should protect a station’s stereophonic service to
what had been the limit of its normally contemplated service radius.
They assert that most stations are located at more than the
minimum mileage required by our rules and such stations therefore
receive stereophonic protection beyond what could be expected at the
minimum distance. We do not doubt that this is the case. Our
mileage requirements are minimums and have never been waived at,
the allotment stage. Moreover, persons seeking new FM stations
desire to serve specific communities. That fact along with the
minimum mileage requirement would result in a location at some
greater distance in almost all cases. If the service areas were
determined solely by the distance to co-channel stations, there would
be many cases where an FM station provided monaural and
stereophonic service to a significantly larger area than that con-
templated by the co-channel separation figures. However, in many
cases, limiting stations are those on adjacent channels.”°
42. Finding that a station’s predicted stereo service area is
limited by co-channel and adjacent channel stations does not mean
that stereo service is unavailable in these areas or that the “losses”
are irreversible. In fact, the new receiver data contained in the
NRSC report indicates that the 20 dB RF D/U ratio provides for
stereophonic reception, if possibly of lesser quality than some parties
believe appropriate, and not just monophonic reception as previously
thought by the Commission and many parties. Several parties used
present protection ratios to claim that their service is being listened
to and enjoyed at the outer edge of their interference-free contours.
Therefore, the arguments suggesting that the signal quality at the
present protection level is “unlistenable” appear highly exaggerated.
Even the listening tests and surveys indicated only that a 30 dB AF
S/N ratio was “annoying” for the “preferred” stereophonic reception
mode. As an alternative to higher protection ratios, persons receiv-
ing service of inferior quality may easily improve it by installing a
directional receiving antenna or improving the performance capabil-
ity of their receiver. In this manner, persons residing in areas
predicted to “lose” service may regain it if they so desire.
43. Several parties also stated that the Commission should
protect a station’s service range from second and third adjacent
channel interference, rather than basing these separations on
substitution of signals.?* Finally, many parties asserted that mobile
20 For example, the stereo service area of station WPGC, Morningside, Maryland is
limited by a single co-channel station (WJAC-FM, Johnstown, Pennsylvania) and
three adjacent channel stations (WFLO-FM, Farmville, Virginia, WFTR-FM,
Front Royal, Virginia; and WFLN-FM, Philadelphia, Pennsylvania).
21 Replacement service assumes that the service of one station will supplant, not
simply interfere with, the service of another station. Using this concept, new
stations must locate outside the predicted service area of stations 2 or 3 channels
removed, and these stations must be outside the service area of the new station.
94 F.C.C. 2d
FM Broadcast Stations 169
G.e., automobile radio) reception problems would be exacerbated if
the distance separations set forth in the Notice were adopted.
44. ABES and ABC both argued that the second and third
adjacent. channel separation requirements should recognize the same
service area as the co-channel and first adjacent channel separation
standards. Not doing so is a direct cause of mobile FM receivers
randomly capturing undesired stations. ABES also claimed that
tuning in the “educational band” (where the primary service range
is given full second and third adjacent channel protection) is
comparatively easy versus tuning in the “commercial band” (where
the replacement service concept permits closer spacing of stations).
It claimed that this difference illustrates the appropriateness of
protecting the primary service contour rather than using the
replacement service concept. As an example of tuning difficulties,
ABES noted mobile reception problems in the Washington-Baltimore
area where 56 stations are assigned in the “commercial” portion of
the FM band. ABES recommended that full protection from second
and third adjacent channel interference be afforded to each station’s
primary service range. ABC and AGK suggested that a compromise
“guardband” solution be adopted if full second and third adjacent
channel! protection standards were unacceptable. Their guardband
compromise was to base the distance separation requirements on a -
40 dB RF D/U ratio for both second and third adjacent channel
separations.?”
45. NTIA, on the other hand, found only minor interference
problems with seven Los Angeles area FM stations that have second
and third adjacent operations at less than minimum separations.
The data did not address whether the public is experiencing
reception problems, except to note that “several station managers
knew of no interference problems.” NAB, in reply, claimed that the
resulting minor interference areas would not be typical because the
receiver data referenced more expensive receivers than the average
ones used by the public.
46. We recognize that some environments cause FM receivers,
particularly mobile receivers, difficulty in maintaining suitable
signal strengths to avoid second and third adjacent channel interfer-
ence. Mobile receivers were not a major planning factor in the
present separation requirements or those proposed in the Notice.
Rather, we used the concept of replacement service. Mobile receiv-
ers, however, are subjected to wide variations in signal strength due
to multipath reflections as they pass through different environments
along highways. In these situations, they are likely to “lock onto”
stronger adjacent channel signals rather than the desired signal.
The Commission believes that the separation distances can be
22 This is the third adjacent channel protection standard required in the educational
portion of the FM band (88-92 MHz). See Section 73.509 of the Rules.
94 FCC. 2d
170 Federal Communications Commission Reports
modified to reduce mobile reception problems and only minimally
affect the potential for additional FM stations. Thus, the rules we are
adopting provide “guardband” protection on second and third
adjacent channels as suggested by ABC and AGK.?3
47. Finally, several parties urged consideration of additional FM
stations on a case-by-case basis, including consideration of direction-
al antennas and terrain.** Cox/Multimedia, however, argued that a
protected contour scheme risks engulfing the FM service with the
interference and processing problems of the AM broadcast service. In
any case, the Commission is not convinced that the benefits of the
Table (i.e., ease of comparing community needs, provision for future
facility growth, and simplicity of processing procedures) should be
abandoned at the present time. Even with the changes adopted
herein, many, if not most, existing stations will be provided the
opportunity for future growth. Although some parties indicated a
preference for the “AM-type” method, this method is too time-
consuming to comport with the Commission’s goals to facilitate
faster processing procedures. The changes adopted herein should
provide the opportunity to establish additional radio stations in
areas of greatest demand that should not be delayed by case-by-case
processing procedures. A go/no-go method as represented by mini-
mum distance requirements still is advantageous and preferred.
Specific proposals
48. Before turning to a discussion of each proposed change, it
may be helpful to reiterate the results of the Commission’s computer
studies on the potential benefits of those changes. Using 200
locations identified as needing additional radio services, the studies
determined how many of these could have an allotment under the
existing rules and each proposed rule change separately. The
resulting progression demonstrates the incremental increase in
availability, i.e., the percentage of locations for which at least one
new allotment was found, for the individual proposals. (The benefits
of each option are set forth in more detail in the individual
discussion of each proposed change and in Appendix B.)
22 Also, the NRSC Report indicated that the second adjacent channel interfering
signal can be 50 dB greater than the desired signal (50 dB RF D/U) and still
provide a 30 dB AF S/N stereophonic output signal. Thus, the -40 dB RF D/U
ratio appears generous for distance separation requirements based on a mono-
phonic reception standard.
Although the use of directional antennas, terrain shielding, and co-location of
transmitters were not proposed in this proceeding, the Commission did request
additional information. We sought guidance on how these methods might be
incorporated into our present Table structure. A variety of information on
increasing FM availability and the potential problems of employing these
techniques were submitted. Specific suggestions related to preservation of the
Table were not provided.
2
ES
94 F.C.C. 2d
FM Broadcast Stations 171
Options Availability
1. Existing rules 1%
2. Class Á stations on Class B/C channels 41%
3. Class B stations in Zone II 41%
4. Additional station classes B1, C2, and C1 43%
5. Uniform protected contour 55%
6. Reclassification (with Option 5) 61%
(without Option 5) 57%
49. Option 2, Class A Stations on Class B/C Channels. This
proposal was opposed by ABC, NBC, and others who suggested that,
although it could result in new assignments in areas outside the
larger radio markets (1.e., outside the top 12 markets), this service
would represent an inefficient use of channels reserved for the wider
area stations. NTIA, on the other hand, suggested that reserving
certain channels for Class A use should be eliminated altogether.
They argued that any class of station should be allowed to operate on
any channel. NAB, in reply comments, argued that this idea would
be contrary to the basic principłe of the Table which ensures stations
for smaller sized markets.
50. Several parties claimed, and our studies confirmed, that this
proposal would provide the single largest increase in availability for
most locations. Our study of 200 locations found that availability of
at least one new station per location would increase from 7% under
the present rules to 41% if this proposal were adopted. Many argued
that these outlets would be a new source of interference outside the
primary service range of existing stations. As stated previously,
however, the Commission believes that the opportunity to establish
additional stations should not be curtailed by providing protection to
secondary service areas. Therefore, we will allow Class A stations to
operate on all channels.
51. NTIA also proposed that Class B and Class C stations be
allowed to operate on Class A channels. However, that change
should offer few potential assignments, and those that are possible
would preclude large areas from future Class A allotments. There-
fore, at this time we will allow Class A operations on any channel,
but other station classes will not be permitted to operate on the Class
Achannels.
52. The Notice further suggested that Class A stations be
permitted to occupy a Class B/C channel only if a Class A channel
were not available. No specific comments addressed this proposed
restriction. The Commission, however, is concerned that defining
2° These parties also argued that adoption of this proposal would result in some
Class A stations operating at a competitive disadvantage to higher power stations.
This issue was addressed in BC Docket No. 80-130. The Commission found there
that intermixture of different classes of stations within the same community
should not be foreclosed as a matter of general policy. In any case, the issue now
before us is not whether different classes of stations may be intermixed in the
same market but whether Class A stations should occupy Class B/C channels.
94 F.C.C. 2d
172 Federal Communications Commission Reports
availability (1.e., reasonable site, city grade coverage, co-location with
AM transmitter, antenna farms, etc.) would be difficult. Therefore,
we have decided not to adopt this restriction because it would require
extensive showings and would be administratively cumbersome to
enforce. We believe the applicant to be the best judge of its
particular situation and accordingly shall not restrict its choice.
Likewise, we will not require these channels to be used by the larger
. class of station first, as some parties urged. To do so might be
counterproductive to the establishment of a local station if a
potential applicant lacked the financial resources to construct and
operate the larger class of station.
53. Options 3 and 4, Intermediate Classes of Stations. The Notice
proposed creating two new classes of stations: Class B1 with facilities
between Classes A and B and Class C1 with facilities between Classes
B and C. It also suggested allowing Class B stations to operate
nationwide. Thus, three classes of stations (Classes A, B1, and B)
would be permitted in Zones I and LA and all five classes (Classes A,
B1, B, C1, and C) in Zone II.
54. Most comments did not focus on allowing Class B stations in
Zone II independently of the other proposals. As pointed out in the
Notice, simply allowing Class B stations to operate in Zone II would
not allow many additional assignments unless the distance separa-
tions were changed.** [The FCC computer studies confirmed that no
increase in availability was possible (Option 3 compared to Option 2)
and only 12 of the Class A stations from Option 2 could become Class
B stations (see Table II of Appendix B).] Consequently, the Notice
proposed to reduce the protected contour of all Class B stations from
0.5 mV/m to 1.0 mV/m.
55. As for the creation of the proposed Class B1 and Class C1
stations, ABC claimed that the A.D. Ring studies proved they would
not be beneficial to the public. It noted that no Class C1 stations
could be identified and the Class B1 stations that were found would
cause interference to existing services over geographic areas that
would exceed the gains from the new services. ABES noted that
additional classes of stations could be supported if variations of the
Notice’s proposals that would provide adequate protection to existing
stations were adopted. Specific modifications were not suggested,
however, except to urge protection of existing interference-free
service areas. NTTA again urged an even greater number of station
classes. It argued that the distribution of service areas for existing
Class B and Class C stations would be more uniform if seven rather
than five classes were adopted. In reply, Cox/Multimedia claimed
that NTIA’s proposal for seven classes does not contain any detailed
26 This occurs because the existing rules require Class B stations to be separated
from co-channel Class C stations by 170 miles, or only 10 miles less than the co-
channel Class C to C requirement of 180 miles.
94 F.C.C. 2d
FM Broadcast Stations 178
technical analysis but merely an assumption that “if five classes of
channels are efficient, seven would be even more efficient.” They
argued that NTIA failed to address the effects of tighter constraints
on station growth, licensee costs, greater levels of predictable
interference, and administrative impact.
56. Although NTIA's seven class proposal may represent more
uniform statistical distribution of existing stations, this is a benefit
of little value and great cost. An analysis of its proposal indicated
only slight differences between co-channel separation requirements
for different classes of stations. For example, NTIA’s Class C1 station
would be separated from a Class C station by 160 miles, while a Class
B station would be separated from the same Class C station by only
156 miles, a difference of only 4 miles. These separations would not
allow stations sufficient room for facility growth or adequate
transmitter site selection. It also would be administratively cumber-
some for the Commission to oversee. While we believe additional
station classes are desirable, a balance must be reached between
complexity and the numbers of potential assignments. Therefore, we
shall not adopt the classes proposed by NTIA.
57. The Commission explored the gains possible if stations with
Class B facilities were assigned in Zone II and protected to the
proposed 1 mV/m contour (i.e., denoted as Class C2),27 We also
explored the proposal to create additional classes of stations so that
existing stations would receive protection more in keeping with the
service rendered. The FCC computer studies examined the number
of assignments possible if three new classes (B1, C2, C1) of stations
were added. Thus, separate classes were studied for the two zones:
Classes A, B1, and B in Zones I and I-A and Classes A, C2, C1 and C
in Zone II. These studies assumed protection of existing stations
equal to that embodied in the present separation requirements. This
option found that availability would only be 43%, compared to the
41% expected by permitting Class A stations to operate on Class B/C
channels (Option 4 versus Option 2). However, the study also
indicated that the stations assigned could operate with greater
facilities. An additional 11 Class B1, 46 Class C2, and 16 Class C1
stations were found (see Table II of Appendix B).
58. Because the larger class of station represents improved
efficiency in terms of service-rendered compared to interference-
caused, the Commission is convinced that adopting these additional
classes of stations would be beneficial.?* We believe that allowing
27 Since the Class B minimum separation requirements depend upon the zone of
operation, stations operating with Class B facilities in Zone II will be termed Class
C2 to avoid confusion with Class B facilities in Zone I.
28 Efficiency according to Docket No. 14185 is defined as: Eff. = 363 x (R/S)2, where
R is the primary service radius of a station and S is the spacing between stations
(see Notice of Inquiry, Notice of Proposed Rule Making, and Memorandum
94 F.C.C. 2d
174 Federal Communications Commission Reports
stations with Class B facilities with modified separation require-
ments in Zone II (Class C2) and creating intermediate classes of
stations (Classes Bi and C1) that serve larger areas than Class A
stations represent major benefits in terms of spectrum efficiency.
59. Option 5, Uniform Protected Contour (1 mV/m). Several
parties submitted detailed showings indicating that changing the
minimum separation requirements to represent a uniform 1 mV/m
protected service contour could severely limit a station’s primary
service range, especially that of Class B stations. Metromedia and
various other parties pointed out that there were specific reasons for
Class B stations currently being based on a 40 mile service range.
They noted that, in 1963, the Commission found that the large
metropolitan communities of the northeast averaged 33 to 40 miles
in radius. They argued, therefore, that a minimum limit of 33 miles
for Class B stations was totally unacceptable for many communities
located in Zone I. ABES stated that such a reduction would be a 32%
loss in primary service area for Class B stations and, in one
particular case, a loss in population of 175,000 persons for each
station located at Indianapolis, Indiana.
60. ABC and others argued that a 1 mV/m protected contour
was previously considered and rejected in 1963 in Docket No. 14185,
They noted than the Commission refused to create a squeezed-in
service by “protecting only the 1 mV/m contour.” Cox submitted
that reducing the minimum spacing would create a system similar to
the AM service and would waste FM’s unique potential for wide-area
service. ABC claimed that this proposal would not represent any
appreciable increase in new FM assignments because only one
addition in the A.D. Ring study was due to reduced separation
requirements. Because the other proposals yielded greater numbers
of potential FM additions, it argued that the uniform protection
proposal would not be instrumental in providing for additional FM
assignments in needy areas. NTIA in reply claimed that both Class A
and Class C stations “have done well” with a 1 mV/m protected
contour and suggested that Class B stations “should be able to also.”
They argued that a decrease in separations would allow new stations
at intermediate distances.
61. ABES focused on the impact of the protection of mobile
receivers and submitted detailed analyses of several situations in the
northeast where several stations are spaced less than the minimum
separation requirements. It claimed that the resulting protection of
only the 1 mV/m contour in these cases has made matters so severe
as to render many signals “unlistenable.” Consequently, reducing
the minimum separation requirements would result in similar areas
where only garbled signals could be received. Because more cities
Opinion and Order at paragraph 39). Thus, the efficiency of co-channel Class C1
stations is 32%, while co-channel Class A stations are only 19% efficient.
94 F.C.C. 2d
FM Broadcast Stations 175
have acquired “New York City-like” architecture that causes
increased signal reflection and diffraction since the present distance
separations were developed, it suggested the Commission avoid any
action that would increase interference to these receivers. ABES
stated that in today’s environment (i.e., tree-lined highways, bridge
abutments, super-highway signs, downtown buildings, etc.), “[t]he
desired signal is subject to very rapid changes in level, beyond the
ability of the receiver signal “leveling” or automatic volume control
to avoid.” It further cited cases in New York City, Philadelphia, and
along the U. S. Route 1 corridor where co-channel and first adjacent
channel stations located at less than minimum spacings have
resulted in many cases of “limited coverage within myriads of
interference.” Thus, ABES argued that greater protection is needed
and the distance separations should not be decreased.
62. The Commission recognized in the Notice that this proposal
would have a substantial impact on the primary service area of
existing Class B stations. Because the present separation require-
ments for Class A and Class C stations afford protection to
approximately the 1 mV/m contour (at .912 and 1.023 mV/m,
respectively, using current propagation curves), they are, for the
most part, unaffected by the proposed change. For the Class B
station, however, this proposal would reflect a change from the .524
mV/m to the 1.0 mV/m field strength contours or a decrease in
primary service range from 40 miles to 33 miles. The Notice,
however, questioned whether the increases in availability justified
reducing the Class B stations’ primary service area. The majority of
the commenting parties, citing the A.D. Ring study statistic of only 1
addition, argued the negative. The FCC computer studies, on the
other hand, revealed that availability would increase from 43%
(Option 4) to 55% with this proposal. Thus, 110 of the 200 study
locations would be provided an opportunity for additional outlets
instead of 86 (see Table I of Appendix B). Also, the number of
stations allowed at these communities would increase from 235 to
332. This new availability, unlike the other proposals under consid-
eration, would be at the expense of the primary service areas of
existing stations. In view of this impact and because urbanized areas
have grown since 1963, the argument against this proposal is most
compelling. The Commission does not consider the incremental
increase in availability to justify the loss of existing primary service
areas. Again, balancing the total number of potential stations
against the potential service rendered, we cannot justify reducing a
station’s expected service area at this time.?°
63. Option 6, Reclassification of Existing Stations. The Notice
29 As noted in comments submitted by Bob Zwick, the Commission is aware that the
1 mV/m contour may be located at a distance of 40 miles by allowing an increase
in facilities for Class B stations. However, this suggestion would not foster the
goal of increasing the availability of FM stations.
94 F.C.C. 2d
176 Federal Communications Commission Reports
further proposed to reclassify all existing stations, after a period of
three years, according to their actual operating facilities. The
Commission noted that many existing stations are operating sub-
stantially below the maximum facilities permitted. Because the
minimum separation requirements assume maximum facilities,
these stations preclude other FM stations from being authorized, yet
do not furnish primary service over the area intended. The three
year period was suggested to give each station the opportunity to
explore its ability to increase facilities and submit an application for
modification of its license.
64. NBC suggested that reclassification of stations where the
need for mutual protection could be demonstrated should not occur.
They argued that if existing stations chose to operate below
minimum facilities, the new assignment “should protect all existing
service areas.” Metromedia did not technically oppose reclassifica-
tion stating that ©. . . it was a more reasonable approach than
reduced distance requirements of providing increased service to the
less populated areas in the West.” Cox and several others, however,
opposed this change, stating that part of FM’s unique identity, which
allows for future expansion, could be destroyed. They argued that
existing licensees would be faced with an unappealing choice. They
either would have to risk present economic investment to increase
their facilities based on estimates of future community growth, or
otherwise be foreclosed from realizing their full potential due to
present circumstances. ABES and others noted that stations may not
be operating with maximum facilities due not only to economic
reasons, but for other reasons as well. They cited the Commission’s
multiple ownership restrictions (Section 73.240), FAA air hazard
limitations, and local zoning restrictions as examples. Because many
of these limitations restrict antenna heights, ABES suggested that
stations be allowed to increase their power to attain the equivalence
of operating with maximum effective radiated power (ERP) and
antenna height above average terrain (HAAT).
65. The Commission realizes that many stations are operating at
less than “full” facilities because of other Commission regulations,
other government agencies” limitations, or restrictions of local
jurisdictions. It is exactly this inconsistency, between the Commis-
sion providing for expansion when the possibility is virtually non-
existent, that we wish to rectify. Rather than viewing reclassification
as discriminatory, the Commission believes that recognizing actual
facility limitations is a realistic means of allowing for additional
outlets. In fact, we view the preclusion of new stations from
relatively underserved communities by stations operating substan-
tially below maximum facilities as being the real case of discrimina-
tion. Additional FCC computer studies verified that availability of
new FM stations could increase from 43% to 57% if reclassification
were considered (see Table III of Appendix B). Because a station's
94 F.C.C. 2d
FM Broadcast Stations 177
classification should reflect its potential, either by spacing require-
ments, economics, or government limitations, the Commission views
reclassification as desirable.
66. The ABES’ suggestion that stations unable to increase their
antenna height be allowed to increase power to attain equivalence of
a station operating at the maximum facilities was considered in
Docket 14185 and rejected. The Commission stated “. . . an increase
in power increases interference more than it does service. Therefore,
we should obviously encourage improvement in service through
greater antenna 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.” [First Report and Order
at para. 79] Because this argument is true today, we must again
reject this alternative.
67. Time Permitted to Upgrade Facilities. The Notice suggested
that existing stations would be given three years to improve their
facilities to the minimum for their class, before any reclassification
took place. It further proposed that new Class C stations have a
period of six years within which to reach minimum facilities before
being reclassified. Since these two proposals consistently were
confused, an explanation appears in order. The first period of 3 years
would apply to all existing licenses, construction permits, or
applications that were authorized, or on file, on the effective date of
this order. Thus, one announced date would be used for evaluating
the facilities of existing stations. The later proposal would continual-
ly be permitted when future Class C applications were authorized.
Because the Class C stations would be the only class with a minimum
antenna height requirement, this time would provide new Class C
stations with an initial opportunity to obtain revenue before possibly
constructing a large antenna tower.
68. The comments failed to provide any specific data that would
support a deadline either longer or shorter than those proposed in
the Notice. ABC argued that three years may be inadequate for
licensees to reach any minimum operating requirements. They
suggested that the Commission authorize liberal extensions of any
deadlines. NTIA fully supported reclassification and submitted 24
months (2 years) as a more than adequate time for expansion.
However, the reply comments of Cox/Multimedia urged that 2 years
was an unrealistic time period to allow stations to make an
application for a change in facilities. Several parties wished to have
an unlimited time in which to effect the changes. Finally, the
difference in the time permitted existing and future stations
received no comment.
69. Lacking details, it is incumbent upon us to balance the public
interest. benefits of the new services possible after reclassification
against the inconvenience to broadcasters. On balance, we believe
that, for simplicity, a single date should apply to all instances. We
94 F.CC. 2d
178 Federal Communications Commission Reports
cannot allow an open-ended time period continually to frustrate the
opportunity to establish the new stations. Nor do we intend to
provide time that is inadequate to consider and submit applications
for facilities equal to or greater than the minimum for a class of
station. In this regard, we emphasize that licensees can protect their
classification merely by filing an application to upgrade their
facilities. It is not necessary that the application be granted or the
construction be completed by the deadline date. Additionally, we
expect that any group seriously contemplating a new Class C service
station should have good economic support and be able to begin
operations with the larger facilities. Specifying a different six year
period for each new Class C authorization would create confusion
and be administatively difficult to implement.
70. Based on a weighing of the benefits and inconveniences, and
considering the delays in reaping the benefits of the other changes
adopted herein, we will indicate a date three years from the effective
date of this order by which all stations must apply for appropriate
minimum facilities. After the 3 year time period for expansion has
expired, a complete listing of the FM Table of Assignments will be
published to indicate the new class designations that reflect the
facilities authorized, or those for which an application has been
filed.39
71. The Commission is also using the opportunity presented by
this proceeding to modify its rules governing “major” and “minor”
modifications of station authorizations. Currently, any modification
that represents a change of 50%, or more, in the area within a
station’s predicted 1 mV/m field strength contour is considered a
major modification of an authorized FM station. Because the
distance separation requirements are based on using maximum
facilities, we believe the procedure to increase facilities (that will be
encouraged by adopting the reclassification proposal) could be
greatly simplified. Therefore, we shall designate these changes as
minor modifications.
Miscellaneous
72. Preferences. Many existing licensees of either Class A or
short-spaced stations requested they be given preference in the
assignment of any new channels which may become available. NPR
and CPB also requested similar preferential treatment be afforded to
80 The Commission does not consider reclassification as a modification of a station's
license. Because the license authorizes only the station’s actual facilities, it would
not have to be altered in anyway. Reclassification is merely the re-designation of
a station’s potential status in a geographic table of channel reservations. Even if
our action could be construed as a license modification, the record adduced in
response to present Notice is entirely sufficient to explore licensees’ concerns, and
they would not be entitled to separate hearings based upon reclassification. See,
WBEN, Inc. v. U.S., 396 F.2d 601 (2nd Cir. 1968)
94 F.C.C. 2d
FM Broadcast Stations 179
educational, noncommercial entities in either the allotment or the
assignment process.** ABC supported establishing assignment priori-
ties including favoring applicants that seek to convert daytime only
AM stations to fulltime local outlets. Several licensees of short-
spaced stations submitted detailed examples of how mutual interfer-
ence problems have curtailed their primary service areas. They also
requested preference in the use of any new allotment that could
alleviate their present circumstances.
73. The Commission is not convinced that this proceeding is the
best vehicle for considering preferences of this type. It has focused on
FM allotment matters rather than questions of channel usage by a
particular entity or group. We believe these questions are more
appropriately considered in separate rule making proceedings fo-
cused on licensing policies rather than allotment rules. For example,
we note that the outstanding Notice of Inquiry and Notice of
Proposed Rule Making in BC Docket No. 82-538, has asked for
comments on the desirability of providing licensees of daytime-only
AM stations a preference for the use of any FM allotments that
might become available in their communities. 47 Fed. Reg. 38937
(published September 3, 1982). We believe that preferences for
daytime-only AM licensees, existing short-spaced FM licensees and
other worthy groups are best resolved in proceedings specifically
devoted to such matters.*?
74. Puerto Rico. Portorican American Broadcasting Co. request-
ed special consideration of the problems encountered in Puerto Rico
because of terrain. It submitted a detailed explanation of the
difficulties experienced trying to improve the facilites of its FM
station WOQI, Ponce, Puerto Rico, by changing its transmitter site.
It urged the Commission to allow flexibility for existing stations to
improve their service before permitting additional outlets on the
island.
75. The Commission again is reluctant to consider rule changes
for individual situations. Instead, we prefer to account for any
specific problems through the present processing methods. In
reviewing Portorican’s comments, we note that its request involves a
waiver to locate at less than minimum spacings to existing FM
stations on the island. Further, it urges grant of the waiver using
calculations employed in the noncommercial, educational section of
the rules (§ 73.509), which is based on protection of existing contours.
31 NPR specifically requested individual channels be reserved for future use in
communities lacking adequate public radio service.
32 We recognize that many licensees of existing stations, including AM daytime
stations, will be interested in seeking the use of the new FM allotments that will
be available as a result of this proceeding. In light of this interest, and in
recognition of the valuable community service that these licensees have provided,
we intend shortly to issue a Notice of Proposed Rule Making proposing procedural
means to facilitate such improvements of existing service.
94 F.C.C. 2d
180 Federal Communications Commission Reports
Inequities because of terrain in Puerto Rico were addressed in the
Fourth Report and Order (Docket No. 14185) adopted in 1964 and
again in a recent Report and Order (BC Docket No. 81-421). We
prefer to continue this pattern and will address any particular
problems that are unique to Puerto Rico in separate proceedings
when needed.
76. Aviation. The Commission also had a request by ARINC and
AOPA to recognize potential increases in interference to aeronauti-
cal navigation and communication services that are immediately
adjacent to the FM broadcast band at 108-136 MHz.** AOPA noted
that according to its surveys 43 locations currently experience
interference and “innumerable” other cases have had to be rectified
through reassignment of aeronautical frequencies. Both argued that
the proposals set forth in the Notice, except for Class A additions,
would have an adverse impact on aviation. They and the FAA also
expressed concern over the encouragement of tall antenna towers,
especially of Class C stations, that intrude into navigable airspace.
77. The problem of potential interference to avionics by FM
stations is well known to the Commission. It has been handled
satisfactorily in the past via coordination procedures with the FAA,
and we are confident that any potential interference problems can
continue to be handled effectively. Finally, we note that the
minimum requirement for antenna height above average terrain
(HAAT) is not a requirement on the antenna tower structure itself.
Thus, it is difficult to estimate the problems that could arise due to
the Class C minimum HAAT requirement. Antenna tower heights
normally are supplied to the FAA at the application stage when
individual antenna height above ground is known. This procedure
should continue to enable us to sort out any potential problems due
to tower heights.
78. Existing short-spaced stations. Short-spaced stations are
those licensed prior to adoption of the minimum distance separation
requirements that failed to meet the new spacings (Fourth Report
and Order in Docket No. 14185). ABES urged the Commission to
correct the defects adopted for consideration of short-spaced stations
in Docket No. 14185 (see Section 73.213). They recommended that
the short-spaced station rules be amended to accord full protection
from second and third adjacent channel interference. They suggest
these cases be administered in a manner similar to the educational
rules (Section 73.509), where actual signal strengths are used to
determine allowable radiation.
79. The Notice stated that the rules governing existing short-
spaced stations would be examined later if necessary. In the
33 These parties indicated that interference to aviation services can be caused by
intermodulation products of two or more FM broadcast signals or by the
combined field strengths from high powered FM stations causing receiver
desensitization.
94 F.C.C. 2d
FM Broadcast Stations 181
meantime we have determined that short-spaced stations shall
continue to be subject to the existing rules. If these stations are
reclassified, separation will be based on their previous class of
station.
80. Implementation. The Commission is aware of the tremendous
interest many groups and individuals have in the outcome of this
proceeding. Since the Notice was adopted, status inquiries have been
made on a daily basis. These contacts and our own investigations
lead us to believe that a pent-up demand will be unleashed after
adoption of the rule changes outlined above. Our goal is to respond to
requests for new allotments as quickly as possible and minimize the
backlog of mutually exclusive petitions. Proceedings addressing such
petitions take considerably longer to resolve and place greater
demands on the Commission’s legal and technical staff than the
routine uncontested proceedings. To facilitate prompt service to the
public, we also desire to process applications quickly.
81. Unfortunately, our present staff resources are not adequate
to respond in a reasonable time even if our expectation of demand is
grossly overstated. Consequently, we will delay the effective date of
the new rules until sufficient staff is available to handle the
increased workload.** When additional resources are made avail-
able, the Commission will begin modifying its computer programs to
permit the use of the new rules. At the same time, we shall institute
a rather large scale rule making to amend the FM Table of
Assignments using approximately 500 locations from the “needs”
list compiled for the Region 2 Conference on AM broadcasting.
82. That rule making will request the public to indicate interest
in the proposed assignments or to propose alternative assignments
by the comment date. Only in that manner can the Commission
avoid receiving an overwhelmingly large number of petitions on the
effective date of the new rules. We believe our course of action is
preferable since it allows us to maintain control over the initial
proposals and any counter proposals that may be made. Similarly,
we shall attempt to avoid the filing of a large number of applications
for new allotments which might occur if a single Report and Order
were adopted that addressed them in toto. Therefore we shall adopt a
series of Reports and Orders addressing the proposed allotments in
individual groups. In this manner, applications should be effectively
metered to correspond to the Commission’s staff resources.
83. Upon completion of the omnibus proceeding, other FM
petitions for amendment of the Table will be accepted and consid-
ered. Before the effective date of the new rules, any petitions or
34 The Senate Commerce Committee has already recommended an increase in the
Commission’s FY 1984 budget to specify funds for the processing of FM petitions
and applications received because of rule changes made in the instant proceeding.
The House Appropriations Committee has also recommended additional FY 1984
funds to increase the staff to respond to the anticipated increased workload.
94 FCC. 2d
182 Federal Communications Commission Reports
applications that do not conform to the “old” rules will be returned.
The Commission regrets that this unusual procedure is necessary.
However, we must be in a position to address petitions and
applications upon the effective date of the new rules and no suitable
alternative exists given our present resources.
84. Metrication. As indicated in the Notice, we believe that this
would be an appropriate time to convert the FM broadcast service to
the International System of Units in order to conform to the
Commission’s program for conversion of all our rules to metric (see
Public Notice, FCC 76-737, July 28, 1976). The Commission believes
the conversions should be realistic values of “convenient” metric
figures rather than a simple multiplication by the appropriate
factor. For example, antenna height maxima will be 100, 150, 300,
and 600 meters rather than the 92, 153, 305, and 610 meters
proposed.** In all cases, the metric term shall be the determining
factor in any discrepancies. Also, the rules adopted today will govern
any disputes that may arise and will take precedence over any other
rule sections which may refer or relate to the changes being made
herein.** Obviously, all circumstances cannot be anticipated. There-
fore, the Commission will offer continuing guidance on this subject
as appropriate.
CONCLUSION
85. Since certain modifications can be made without affecting
the primary service areas of existing stations and there appear to be
many underserved locations, the Commission is persuaded that
changes to the FM allotment rules are appropriate. Therefore, we
shall: (1) allow Class A stations to operate on all channels, (2)
authorize three new classes of stations, and (3) reclassify existing
stations, after a period of three years, according to their operating
facilities.
86. Although every effort has been made to hold constant the
present degree of expected service, a station’s existing predicted
primary service area may change slightly due to the introduction of
new classes of stations, reclassification, or conversion to the Interna-
tional System of Units. Any subsequent additions to the FM Table of
35 We recognize that some requirements will increase while others will decrease.
However, conversion to convenient numbers is preferred notwithstanding any
slight modifications that may result. Of course, all stations operating with
facilities in excess of the maximums adopted will be permitted to continue
operating with their existing facilities.
36 All factors have been converted to the appropriate decimal place of their metric
equivalent. For convenience, some conversion factors are listed below:
meters = .3048 x feet
kilometers = 1.609x miles
square kilometers = .386 x square miles
94 F.C.C. 2d
FM Broadcast Stations 183
Assignments resulting in the operation of new stations will be in
accordance with the rules established herein, and as such their
operation will not constitute a modification of existing licenses under
Section 316 of the Communications Act of 1934, as amended. WBEN,
Inc. v. United States, 396 F. 2d 601 (2nd Cir. 1968). Accordingly,
hearings at the time of actual individual changes are not required
and are not anticipated. In view of the detailed nature of this
proceeding, we are confident that the Mass Media Bureau expedi-
tiously can resolve disputes which may arise as a result of the
conversion process. Accordingly, we delegate to the Chief, Mass
Media Bureau, such authority.
87. Because the Commission wishes to adopt new classes of
stations but reject the uniform protection standard of 1 mV/m (60
dBu), slight adjustments have been made to the proposed facilities of
the new classes of stations. Although three additional classes (Class
B1, B, and C1) were proposed for Zone II, we believe that the two
chosen offer approximately the same variety as the three intended
under the uniform protection standard.*” Therefore, the following is
a summary of the classes, maximum facilities, allowed zone, and, for
reference only, the approximate co-channel primary service ranges
and resultant field strengths:
Maximum Service
Station Facilities Permitted Radius Field Strength
Class kW & m.fft.) Zone km.(mi.) mV/m (dBu)
A 3 & 100 (328) 18:2 24 (15) 1.0 (60)
Bl 25 & 100 (328) 1 45 (28) 7 (57)
B 50 & 150 (492) 1 64 (40) 5 (54)
C2 50 & 150 (492) 2 52 (32) 1.0 (60)
C1 100 & 300 (984) 2 72 (45) 1.0 (60)
c 100 & 600 (1968) 2 92 (57) 1.0 (60)
88. NTIA also suggested that minimum facilities be based on the
distance to the 1 mV /m (60 dBu) contour. Although this coverage is
an important consideration, the determining factor must be a
station's authorized power and minimum antenna heights are, in
most cases, unduly restrictive. The Commission continues to believe
that the city grade signal requirement is normally the best way to
enforce minimum areas of service. Only Class C stations will have a
minimum antenna height requirement to exceed the Class C1
maximum of 300 meters (984 feet). Some parties expressed the
opinion that this would be a discriminatory policy toward Class C
licensees. ABES and others questioned the choice of the minimum
37 The definition of Class Cl was kept in order to avoid confusion with the Canadian
Class C1 that also is allowed 100 kW ERP and 300 meters HAAT. This results in
Class C2 denoting a smaller facility station than Class C1, Although the Class C2
would be allowed the same facilities as a Class B station, its service radius would
only be 52 kilometers (32 miles) rather than the 64 kilometer (40 mile) range of
the Class B.
94 F.C.C. 2d
184 Federal Communications Commission Reports
height requirement for Class C stations and said that simply
choosing one-half the existing maximum height was arbitrary. The
Commission, however, is convinced from its own records and the data
submitted by NTIA that an antenna height of 600 meters (1968 feet)
HAAT is an unrealistic expectation for most of the country. While
we do not wish to foreclose the possibility of this extended coverage
station altogether, the Commission believes that, since 80% of the
Class C facilities operate below the Class C1 requirements, recogniz-
ing this condition via a minimum antenna height is completely
justifiable.
89. On the other hand, we are attempting to better define a
station’s class based on its operating facilities. Since the station
should clearly belong to one class of station, minimum power
requirements will be set as proposed. Therefore, the minimum power
per class must exceed the maximum of the next lower class for its
zone, except for Class A stations which will continue to have a
minimum requirement of 100 watts.
90. The Commission also is adopting an amended distance
separation table to incorporate the new classes of stations. New
separations are inserted for the new class relationships that recog-
nize that interference within the primary service ranges for each
class of station does not exceed an undesired to desired ratio of 1:10 (-
20dB) for co-channel stations and 1:2 (-6dB) for first-adjacent channel
stations. The existing co-channel and first adjacent channel separa-
tions are the approximate metric equivalent rounded off to the
nearest kilometer. The second and third adjacent channel separa-
tions represent either the existing spacings converted to kilometers
or the “guardband compromise” of not allowing the undesired signal
to exceed the desired signal by 100:1 (40 dBu) within the desired
station’s primary service range, whichever is greater. Finally, the
distances for stations separated by 53 or 54 channels correspond to
those of the major station classification as proposed in the Notice.
91. Those allotments and assignments which are within 320
kilometers (199 miles) of the Canadian or Mexican border must
conform to the requirements specified in the FM Broadcast Agree-
ment existing between the United States and the respective country.
Since the present agreements do not acknowledge Class B1, Class C2,
and, in the case of Mexico, Class C1 stations, these classes of stations
must meet the criteria of the Class B or Class C station classes. Thus,
the new distance separation requiréments are presented in three
separate tables depending upon whether the allotments and assign-
ments to be considered are located in the United States, Canada, or
Mexico.
92. According to the definitions adopted at the 1979 World
Administrative Radio Conference (WARC) of the International
Telecommunications Union, the term “allotment” rather than
“assignment” more closely identifies the designation of a frequency
94 F.C.C. 2d
FM Broadcast Stations 185
or channel for use in a specific geographic area. Assignment is the
authorization of a radio frequency channel for use by an entity under
specific conditions. Thus, a channel may be allotted to a community
or place but assigned to a licensee. A plan of potential channel
designations should be referred to as Table of Allotments. The rules
will be amended to denote the Table as the: Table of FM Allotments.
93. In view of the foregoing, IT IS ORDERED, pursuant to the
authority of $$ 4(1), 303(f), (g) and (r) and 307(b) of the Communica-
tions Act of 1934, as amended, that the rules are amended as set
forth in the attached Appendix C, effective on the date specified in a
future public notice issued by the Commission indicating that
resources have been made available for implementing the new rules
(see paragraphs 80 thru 83, supra).
94. IT IS FURTHER ORDERED, That this proceeding IS TER-
MINATED. For further information on this matter contact Kathryn
S. Hosford, Mass Media Bureau, (202) 632-9660.
FEDERAL COMMUNICATIONS COMMISSION
WILLIAM J. TRICARICO, Secretary
* Appendices A, B, and Figures 1 and 2 - may be seen in the
FCC Dockets Branch.
APPENDIX ©
1. Section 73.202 is amended by revising the headnote, paragraph (a) and the heading
title of paragraph (b) to read as follows:
373.202 Table of Allotments.
(a) General. The following Table of Allotments contains the channels (other than
noncommercial educational Channels 201-220) designated for use in communities in
the United States, its territories, and possessions. All listed channels are for Class B
stations in Zones I and LA and for Class C stations in Zone II unless otherwise
specifically designated.
(1) Channels designated with an asterisk may only be used by noncommercial
educational broadcast stations. Noncommercial educational FM allotments (Chan-
nels 201-220) available for use in various communities in Arizona, California, New
Mexico, and Texas are listed in §73.504. The rules governing the use of noncommer-
cial educational channels in other communities are contained in §73.501.
(2) Each channel listed in the Table of Allotments reflects the class of station that
is authorized, or has an application filed, to use it based on the minimum and
maximum facility requirements for each class contained in §73.211.
Note. The provisions of this subparagraph [(a)(2)] become effective [3 years from the
effective date of the Report and Order in BC Docket 80-90.].
(b) Table of FM Allotments.
* * * * *
2. Section 73.203 is revised in its entirety to read as follows:
§73.203 Availability of channels.
Applications may be filed to construct FM broadcast stations only at the communi-
94 FOC. 2d
186 Federal Communications Commission Reports
ties and on the channels contained in the Table of Allotments (§73.202(b)). Applica-
tions that fail to comply with this requirement, whether or not accompanied by a
petition to amend the Table, will not be accepted for filing. However, applications
specifying channels that accord with publicly announced FCC orders changing the
Table of Allotments will be accepted for filing even though such applications are
tendered before the effective dates of such channel changes.
3. Section 73.204 is revised to read as follows:
373.204 International agreements and other restrictions on use of channels.
See §§73.207, 73.220, and 73.1650.
4. Section 73,205 is amended by revising the introductory text to read as follows:
§73.205 Zones.
For the purpose of allotments and assignments, the United States is divided into
three zones as follows:
5. Section 73.206 is revised in its entirety to read as follows: §73.206 Classes of stations
and permissible channels.
(a) The following frequencies are reserved for use by Class A stations:
Frequency Channel Frequency Channel
(MHz) Number (MHz) Number
92.1 221 100.1 261
92.7 224 100.9 265
93.5 228 101.7 269
94.3 232 102.3 272
95.3 237 103.1 276
95.9 240 103.9 280
96.7 244 104.9 285
97.7 249 105.5 288
98.3 252 106.3 292
99.3 257 107.1 296
(b) Stations designated as Class A, B1, and B may be authorized in Zones I and I-A.
Classes A, C2, C1, and C may be authorized in Zone II. The facilities for each class of
station are listed in $73.211. The 20 channels listed in paragraph (a) of this Section
may only be used by Class A stations but the other channels may be used by any class
of station.
(c) The rules applicable to a particular station, including minimum and maximum
facility requirements, are determined by its class. Class designation is based on the
zone in which the station’s transmitter is located, or proposed to be located.
6. Section 73.207 is amended by revising paragraphs (a) and (b) to read as follows:
$73.207 Minimum distance separation between stations.
(a) FM allotments and assignments must be separated from other allotments and
assignments on the same channel and five adjacent channels by certain minimum
distances. If transmitter sites do not meet the minimum distances listed in paragraph
(b) of this Section, the Commission will not accept petitions to amend the Table of
Allotments, applications for new stations, or applications to change the channel or
location of existing assignments. Class D (secondary) assignments, however, are
subject only to the separation distances contained in subparagraph X3). (See Section
73.512 for other rules governing the channel and location of Class D (secondary)
assignments.)
94 F.C.C. 2d
FM Broadcast Stations 187
(b) The distances listed below apply only to allotments and assignments operating on
the same channel or one of five critical channels adjacent to the desired channel. The
five adjacent channels are the first (200 kHz removed from the main channel), the
second (400 kHz removed), the third (600 kHz removed), the fifty-third (10.6 MHz
removed), and the fifty-fourth (10.8 MHz removed). The distances shown must be met
regardless of which is the proposed station (i.e., distances shown from a new Class A
station to an existing Class C station are also the distances between a new Class C
station and an existing Class A station).
(1) Allotments and assignments in the United States must be separated from other
domestic allotments and assignments by the following minimum distances.
Table A
MINIMUM DISTANCE SEPARATION REQUIREMENTS
in kilometers (miles)
Relation Co-channel 200 kHz 400/600 kHz 10.6/10.8 MHz
AtoA 105 (65) 64 (40) 27 (17) 8 (5)
A to BL 138 (86) 89 (55) 48 (30) 8 (65)
A to B 163 (101) 105 (65) 69 (43) 16 (10)
A to C2 163 (101) 103 (64) 55 (34) 32 (20)
A to Cl 196 (122) 129 (80) 74 (46) 32 (20)
AtoC 222 (138) 169 (105) 105 (65) 32 (20)
B1 to Bl 175 (109) 114 (71) 50 (31) 24 (15)
Bl to B 211 (131) 145 (90) 71 (44) 24 (15)
B1 to C2 200 (124) 134 (83) 56 (35) 40 (25)
Bi to Cl 233 (145) 161 (100) 77 (48) 40 (25)
Bl to C 259 (161) 193 (120) 97 (60) 40 (25)
B to B 241 (150) 169 (105) 74 (46) 24 (15)
B to C2 237 (147) 164 (102) 74 (46) 40 (25)
B to Cl 270 (168) 195 (121) 79 (49) 40 (25)
B to C 274 (170) 217 (135) 105 (65) 40 (25)
C2 to C2 190 (118) 130 (81) 58 (36) 48 (30)
C2 to Ch 224 (139) 158 (98) 77 (49) 48 (30)
C2 to C 249 (155) 188 (117) 98 (61) 48 (30)
C1 to C1 245 (152) 177 (110) 82 (51) 48 (30)
Cl to € 270 (168) 209 (130) 101 (63) 48 (30)
Cto C 290 (180) 241 (150) 105 (65) 48 (30)
(2) G) Under the Canada-United States FM Broadcasting Agreement, domestic U.S.
allotments and assignments that are located within 320 kilometers (199 miles) of the
common border must be separated from Canadian allotments and assignments by
the following distances. Class B1 and Class C2 allotments and assignments must be
considered Class B allotments and assignments when using this table.
Table B
MINIMUM DISTANCES SEPARATION REQUIREMENTS
in kilometers (miles)
Relation Co-channel 200 kHz 400 kHz 600 kHz
AtoA 145 (90) 80 (50) 40 (25) 32 (20)
AtoB 217 (135) 137 (85) 72 (45) 64 (40)
A to C1 241 (150) 161 (100) 105 (65) 97 (60)
AtoC 241 (150) 193 (120) 121 (75) 113 (70)
B to B 249 (155) 169 (105) 97 (60) 72 (45)
B to C1 274 (170) 201 (125) 121 (75) 97 (60)
B toC 274 (170) 225 (140) 137 (85) 113 (70)
C1 to CI 306 (190) 225 (140) 145 (90) 113 (70)
C1 to € 306 (190) 249 (155) 169 (105) 121 (75)
C toC 306 (190) 257 (160) 169 (105) 129 (80)
94 F.C.C. 2d
188 Federal Communications Commission Reports
Gi) Under the Canada-United States FM Broadcasting Agreement, a short
spacing of up to 8 kilometers (5 miles) in the direction of a related station may be
considered acceptable depending on the circumstances of each individual case.
(3) Under the Mexican-United States FM Broadcasting Agreement, U.S. allotments
and assignments located within 320 kilometers (199 miles) of the common border
must be separated from Mexican allotments and assignments by the following
distances. Class B1 and Class C2 allotments and assignments must be considered
Class B and Class C1 allotments and assignments must be considered Class C when
using this table.
Table C
MINIMUM DISTANCE SEPARATION REQUIREMENTS
in kilometers (miles)
Relation Co-channel 200 kHz 400/600 kHz 10.6/10.8 MHz
AtoA 105 (65) 65 (40) 25 (15) 8 (a)
A to B 175 (110) 105 (65) 65 (40) 16 (10)
A toC 210 (130) 170 (105) 105 (65) 32 (20)
A to D 95 (60) 50 (30) 25 (15) 8 (5)
B to B 240 (150) 170 (105) 65 (40) 25 (15)
B to C 270 (170) 215 (135) 105 (65) 40 (25)
B to D 170 (105) 95 (60) 65 (40) 16 (10)
C to C 290 (180) 170 (150) 105 (65) 48 (30)
Cto D 200 (125) 155 (95) 105 (65) 25 (15)
D to D 18 (11) 10 (6) 5 (3) 3 (2)
7. Section 73.208 is amended by revising paragraphs (a), (b) (2), and (c) to read as
follows:
§ 73.208 Reference points and distance computations.
(a) (1) The following reference points must be used to determine distance separation
requirements when petitions to amend the Table of Allotments (§ 73.202(b)) are
considered:
firstly, transmitter sites if authorized;
secondly, reference coordinates designated by the FCC;
thirdly, coordinates listed in the United States Department of Interior publication
entitled Index to the National Atlas of the United States of America; or
lastly, coordinates of the main post office.
(The community’s reference points for which the petition is submitted will normally
be the coordinates listed in the above publication.)
(2) When the distance between communities is calculated using community
reference points and it does not meet the minimum separation requirements of $
78.207, the channel may still be allotted if a transmitter site is available that would
meet the minimum separation requirements and still permit the proposed station to
meet the minimum field strength requirements of § 73.315. A showing indicating the
availability of a suitable site should be submitted with the petition. In cases where a
station is not authorized in a community or communities and the proposed channel
cannot meet the separation requirement a showing should also be made indicating
adequate distance between suitable transmitter sites for all communities.
b* * *
94 F.C.C. 2d
FM Broadcast Stations 189
(2) The coordinates of the other community as listed in the publication listed in
paragraph (a) of this Section; or, if not contained therein,
* + * + =
te) The distance between reference points is considered to be the length of the
hypotenuse of a right triangle, one side of which is the difference in latitude of the
reference points and the other side the difference in longitude of the two reference
points. Distance must be computed by the method given in this paragraph. (This
method may be used to accurately determine distances up to 350 kilometers (217
miles)). For these distances, this method will normally be more accurate than
calculations using spherical trigonometry that do not correct for the spheriodal shape
of the earth. Its accuracy deteriorates rapidly, however, for distances beyond 475
kilometers (295 miles) and it should not be used in those cases.
(1) Convert the latitudes and longitudes to degrees and decimal parts of a degree in
accordance with Table I of $ 73.698.
(2) Determine the middie latitude of the two reference points to the nearest second
of latitude (average the latitudes of the two points).
LATm = (LAT: + LAT»)/2
(3) Determine the number of kilometers per degree of latitude difference for the
appropriate middle latitude.
LAT; = 111.108 - .566 cos(2 LAT»)
(4) Determine the number of kilometers per degree of longitude difference for the
appropriate middle latitude.
LONGx = 111.391 cos(LATm) — .095 cos(3 LATn)
(5) Determine the north-south distance in kilometers.
LAT = LAT: (LAT, - LAT»)
(6) Determine the east-west distance in kilometers.
LONG = LONG: (LONG: - LONG»)
(7) Determine the distance between the reference points by the square root of the
sum of the squares of the distance obtained.
DIST = (LAT? + LONG?)
where:
LAT; € LONG: = coordinates of one location in decimal degrees.
LAT: & LONG» = coordinates of second location in decimal degrees,
LAT = middle latitude between points,
LAT: = kilometers per degree of latitude difference
LONG» = kilometers per degree of longitude difference,
LAT = north-south distance in kilometers,
LONG = east-west distance in kilometers, and
DIST = distance between two reference points in kilometers.
In computing the above, sufficient decimal figures must be used to determine the
distance to the nearest kilometer.
94 F.C.C. 2d
190 Federal Communications Commission Reports
8. Section 73.209 is amended by revising paragraphs (b) and (c) to read as follows:
§ 73.209 Protection from interference.
* = * * *
(b) The nature and extent of the protection from interference accorded FM broadcast
stations operating on Channels 221-300 is limited solely to the protection that results
from the distance separation requirements and the rules governing maximum power
and antenna heights. These rules are specified in this Sub part.
(c) When the FCC determines that grant of an application would serve the public
interest, convenience, and necessity, an antenna location may be specified in a
designated antenna farm area that results in separations less than those specified in
this Sub part. All FM allotments and assignments must be afforded protection from
interference equivalent to the protection afforded under the minimum separations
specified in this Sub part.
9, Section 73.211 is revised in its entirety to read as follows:
§ 73.211 Power and antenna height requirements.
(a) Minimum requirements. (1) Except as provided in paragraph (b)(2) of this Section,
the minimum effective radiated power for:
Class A stations must equal 0.1 kW (10 dBk);
Class B1 stations must exceed 3kW (4.8 dBk);
Class B stations must exceed 25 kW (14 dBk);
Class C2 stations must exceed 3 kW (4.8 dBk);
Class C1 stations must exceed 50 kW (17 dBk); and
Class C stations must equal 100 kW (20 dBk).
(2) Class C stations must have a minimum antenna height above average terrain of
at least 300 meters (984 feet). No minimum antenna height above average terrain is
specified for Classes A, B1, B, C2, or C1 stations.
(b) Maximum power and antenna height. (1) The maximum effective radiated power
in any direction and maximum antenna height above average terrain (HAAT) for the
various classes of stations are listed below:
Maximum antenna HAAT
Class Maximum Power in meters (feet)
A 3kW (4.8 dBk) 100 (328)
B1 25 kW (14.0 dBk) 100 (328)
B 50 kW (17.0 dBk) 150 (492)
cz 50 kW (17.0 dBk) 150 (492)
Cl 100 kW (20.0 dBk) 300 (984)
c 100 kW (20.0 dBk) 600 (1968)
(2) Antenna heights may exceed that specified in this paragraph if the effective
radiated power is reduced so that the distance to the 1 mV/m (60dBu) contour
extends no farther than it would if the station were operating with the maximum
power and antenna HAAT for its particular class of station. The location of the 1
mV/m (60 dBu) contour is determined using Figure 1 of § 73.333. The antenna
HAAT is determined using the procedure contained in § 73.313. When antenna
HAAT is less than 30 meters (100 feet), an antenna HAAT of 30 meter (100 feet)
must be assumed to determine equivalence. When a station’s effective radiated
power must be reduced below the normal minimum for its class (specified in
paragraph (a\(1) of this Section) the value determined will be the minimum for the
particular station involved.
94 F.C.C. 2d
FM Broadcast Stations 191
(3) For Class B stations in Puerto Rico and the Virgin Islands, a maximum antenna
HAAT of 600 meters (1968 feet) with an effective radiated power of 25 kW will be
allowed. For antenna heights above 600 meters (1968 feet), the power must be
reduced so that the station’s 1 mV/m contour (located pursuant to Figure 1 of §
73.333) will extend no farther from the station’s transmitter than with the
maximum facilities allowed. For powers above 25 kW (up to 50 kW), no antenna
height will be authorized that results in greater coverage by the 1 mV/m contour
than can be obtained with the maximum facilities.
(c) Existing stations. Stations authorized prior to [the effective date of the Report and
Order in BC Docket 80-90] that do not conform to the requirements of this Section,
may continue to operate as authorized. Stations operating with facilities in excess of
those specified in paragraph (b) of this Section may not increase their effective
radiated powers or extend their 1 mV/m field strength contour beyond the location
permitted by their present authorizations. The provisions of this Section will not
apply to applications to increase facilities for those stations operating with less than
the minimum power specified in paragraph (a) of this Section.
10. Section 73.212 is amended by revising paragraph (b) to read as follows:
§ 73.212 Administrative changes in authorizations.
* * * * *
(b) Antenna heights above average terrain will be rounded out to the nearest meter.
11. Section 73.213 is amended by revising paragraphs (a), (e), and subparagraphs
(Di) and (iii) to read as follows:
$ 78.213 Stations and spacings below the minimum separations.
(a) Stations authorized prior to November 16, 1964, at locations that do not meet the
minimum distances specified in $ 73.207 may apply for changes in facilities if the
requested facilities conform to those listed in the following table:
Facilities To Be Authorized For Short-Spaced FM Stations
Facilities authorized
Class of Separation in kilometers Power Antenna height
Station Co-channel First adjacent (kW) (meters)
A to A 72-105 3 100
AtoA 64-71 2 100
A to A less than 64 1 100
A to B 80-105 3 100 Class A
50 150 Class B
A to B 64-79 3 100 Class A
20 150 Class B
A to B less than 64 3 100 Class A
10 150 Class B
A to C 129-169 3 100 Class A
100 600 Class C
A toC 97-128 3 100 Class A
50 600 Class C
A to © less than 97 3 100 Class A
100 600 Class C
BtoB 201-241 129-169 50 150
BtoB 161-200 105-128 20 150
BtoB 121-160 80-104 10 150
B to B less than 121 less than 80 5 150
B to C 225-274 177-217 50 150 Class B
100 600 Class C
94 F.C.C. 2d
192 Federal Communications Commission Reports
BtoC 177-224 137-176 20 150 Class B
50 600 Class C
B to C 145-176 97-136 10 150 Class B
20 600 Class C
BtoC less than 145 less than 97 5 150 Class B
10 600 Class C
CtoC 241-290 201-241 100 600
Cto € 193-240 153-200 50 600
CtoC 161-192 121-152 20 600
Cto C less than 161 less than 121 10 600
+ . * * *
(e) The powers listed in the table are the maximums the FCC will authorize.
Antenna heights may exceed those specified in the table if the effective radiated
power is reduced so that the 1 mV/m contour extends no further than it would with
the maximum power and antenna height. The antenna height value to be used is that
above average terrain and not that in any particular direction. When antenna heights
are less than 30 meters (100 feet), a value of 30 meters (100 feet) must be assumed for
the purposes of this paragraph.
ore?
(2) * *
(Da? GP”
(ii) When a station does not meet the minimum separations to co-channel or first
adjacent channel stations, it may apply for up to the maximum listed facilities for
the separations that would exist at the new transmitter site. (See subdivision (iii) of
this subparagraph for further restrictions on very short-spaced stations).
Gii) The provisions of this subparagraph apply where the resulting separation
after the move would be less than: co-channel, 64 kilometers Class A to Class A,
121 kilometers Class B to Class B, 145 kilometers Class B to C or vice versa, or 161
kilometers Class C to Class C; first adjacent channel 64 kilometers Class A to Class
B or vice versa, 80 kilometers Class B to Class B, 97 kilometers Class A or B to
Class C, or vice versa, and 121 kilometers Class C to Class C. Stations so situated
may apply to move and use either their present facilities or no more than those
specified for their distance brackets in paragraph (a) of this Section, if the move
would not decrease the short distance by more than 5 kilometers. If the move
would decrease the short distance a greater amount, a station will be permitted no
more than the facilities that would give it, in the critical direction, a 1 mV/m
contour located no further out than that which would result from using the former
location and the maximum facilities specified for the distance bracket.
Note. For the purposes of the above Section, Classes B1 and C2 will be considered
Class B and Class C1 will be considered Class C until further notice.
12. Section 73.220 amended.
In paragraph (a) the phrase “500 feet” is revised to read “150 meters (492 feet).”
13, Section 73.240 amended.
In paragraph (aX2) the phase “100 miles” is revised to read “160 kilometers (100
miles).”
14. Section 73.310 is amended by revising the headnote and the first two definitions in
paragraph (a) to read as follows:
94 F.C.C. 2d
FM Broadcast Stations 193
§ 73.310 FM technical definitions.
(a) Antenna height above average terrain, (HAAT). HAAT is calculated by:
determining the average of the antenna heights above the terrain from 3 to 16
kilometers (2 to 10 miles) from the antenna for the eight directions evenly spaced for
each 45 ° of azimuth starting with True North (a different antenna height will be
determined in each direction from the antenna); and computing the average of these
separate heights. In some cases less than eight directions may be used, (See $
73.313(d).) Where circular or elliptical polarization is used, the antenna height above
average terrain must be based upon the height of the radiation of the antenna that
transmits the horizontal component of radiation.
Antenna power gain. The square of the ratio of the root-mean-square (RMS) free
space field strength produced at 1 kilometer in the horizontal plane in millivolts per
meter for 1 kW antenna input power to 221.4 mV/m. This ratio is expressed in
decibels (dB). If specified for a particular direction, antenna power gain is based on the
field strength in that direction only.
* + * n =
15. Section 73.313 is amended by revising paragraphs (c) [introduction], (cX1), (d), (e),
(£), (g), and (h) to read as follows:
$ 73.313 Prediction of coverage.
* * * * *
(c) In predicting the distance to the field strength contours, the F(50,50) field
strength chart, Figure 1 of $ 73.333 must be used. The 50% field strength is defined as
that value exceeded for 50% of the time.
(1) The F(50,50) chart gives the estimated 50% field strengths exceeded at 50% of
the locations in dB above 1 uV/m. The chart is based on an effective power radiated
from a half-wave dipole antenna in free space, that produces an unattenuated field
strength at 1 kilometer of about 107 dB above 1 uV/m (221.4 mV/m).
» * * * *
(d) The antenna height to be used with this chart is the height of the radiation center
of the antenna above the average terrain along the radial in question. In determining
the average elevation of the terrain, the elevations between 3 and 16 kilometers from
the antenna site are used.
(1) Profile graphs must be drawn for eight radials beginning at the antenna site
and extending 16 kilometers therefrom. The radials should be drawn for each 45 ° of
azimuth starting with True North. At least one radial must include the principal
community to be served even though it may be more than 16 kilometers from the
antenna 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, these radials must not be used in computing the antenna height above
average terrain.
(2) Where the 3 to 16 kilometers 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 16 kilometers portion of
the radial, the entire 3 to 16 kilometers portion of the radial must be included in the
computation of antenna height above average terrain. However, where the 50 uV/m
contour does not so encompass United States land area and (i) the entire 3 to 16
kilometers portion of the radial extends over large bodies of water or foreign
territory, such radial must be completely omitted from the computation of antenna
height above average terrain, and (ii) where a part of the 3 to 16 kilometers portion
of a radial extends over large bodies of water or over foreign territory, only that part
of the radial extending from the 3 kilometers sector to the outermost portion of land
94 F.C.C. 2d
194 Federal Communications Commission Reports
area within the United States covered by the radial must be used in the computation
of antenna height above average terrain.
(3) The profile graph for each radial should be plotted by contour intervals of from
12 to 30 meters and, where the data permits, at least 50 points of elevation
(generally uniformly spaced) should be used for each radial. In instances of very
rugged terrain where the use of contour intervals of 30 meters would result in
several points in a short distance, 60 or 120 meter contour intervals may be used for
such distances. On the other hand, where the terrain is uniform or gently sloping
the smallest contour interval indicated on the topographic map should be used,
although only relatively few points may be available. The profile graph should
indicate the topography accurately for each radial, and the graphs should be plotted
with the distance in kilometers as the abscissa and the elevation in meters above
mean sea level as the ordinate. The profile graphs should indicate the source of the
topographical data used. 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 that shows the curvature of the earth. It is not necessary to
take the curvature of the earth into consideration in this procedure, as this factor is
taken care of in the charts showing signal strengths. The average elevation of the 13
kilometer distance between 3 and 16 kilometers 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% of the distance) in sectors and
averaging those values.
(4) Examples of HAAT calculations:
(i) The heights above average terrain on the eight radials are as follows:
Meters
0° 120
45° 255
90° 185
135° 90
180° -10
225° -85
270° 40
315° 85
The antenna height above terrain (defined in § 73.310(a)) is computed as follows:
(120 + 255 + 185 + 90 - 10 - 85 + 40 + 85) / 8 = 85 meters.
(ii) Same as (i), except the O ° radial is entirely over sea water. The antenna
height above average terrain is computed as follows (note that the divisor is 7 not
8):
(255 + 185 + 90 - 10-85 + 40 + 85) / 7 = 80 meters.
(iii) Same as (i), except that only the first 10 kilometers of the 90 ° radial are in
the United States; beyond 10 kilometers the 90 ° radial is in a foreign country. The
height above average terrain of the 3 to 10 kilometer portion of the 90 ° radial is
105 meters. The antenna height above average terrain is computed as follows (note
that the divisor is 8 not 7,5):
(120 + 255 + 105 + 90 - 10 - 85 + 40 + 85) / 8 = 75 meters.
(e) In cases where the terrain in one or more directions from the antenna site
departs widely from the average elevation of the 3 to 16 kilometer sector, the
prediction method may indicate contour distances that are different from what may
94 F.C.C. 2d
FM Broadcast Stations 195
be expected in practice. For example, a mountain ridge may indicate the practical
limit of service although the prediction method may indicate otherwise. In such cases,
the prediction method should be followed, but a supplemental showing may be made
concerning the contour distances as determined by other means. Such supplemental
showings should describe the procedure used 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, these should include the area obtained by the regular prediction
method and the area obtained by the supplemental method. In directions where the’
terrain is such that antenna heights less than 30 meters for the 3 to 16 kilometer
sector are obtained, an assumed height of 30 meters must be used for the prediction of
coverage. However, where the actual contour distances are critical factors, a
supplemental showing of expected coverage must be included together with a
description of the method used in predicting such coverage. In special cases, the FCC
may require additional information as to terrain and coverage.
(f) The effect of terrain roughness on the predicted field strength of a signal at points
distant from an FM transmitting antenna is assumed to depend on the magnitude ofa
terrain roughness factor (h) which, for a specific propagation path, is determined by
the characteristics of a segment of the terrain profile for that path 40 kilometers in
length located between 10 and 50 kilometers from the antenna. The terrain roughness
factor has a value equal to the distance, in meters, between elevations exceeded by all
points on the profile for 10% and 90% respectively, of the length of the profile
segment. (See $ 73,333, Figure 4.)
(8) If the lowest field strength value of interest is initially predicted to occur over a
particular propagation path at a distance that is less than 50 kilometers from the
antenna, the terrain profile segment used in the determination of terrain roughness
factor over that path must be that included between points 10 kilometers from the
transmitter. and such lesser distances. No terrain roughness correction need be
applied when all field strength values of interest are predicted to occur 10 kilometers
or less from the transmitting antenna.
(h) Profile segments prepared for terrain roughness factor determinations are to be
plotted in rectangular coordinates, with no less than 50 points evenly spaced within
the segment using data obtained from topographic maps with contour intervals of
approximately 15 meters (50 feet) or less if available.
* * x * *
16. Section 73.314 is amended by revising paragraphs (b)(1\ii), (b)(2) [introduction],
and subparagraphs (ii), (v), (vii), and (viii) to read as follows:
§ 73.314 Field strength measurements.
b* * *
Met?
BD * *
(ii) Each radial is marked, at a point exactly 16 kilometers from the transmitter
and, at greater distances, at successive 3 kilometer intervals. Where measure-
ments are to be conducted over extremely rugged terrain, shorter intervals may be
used, but all such intervals must be of equal length. Accessible roads intersecting
each radial as nearly as possible at each 3 kilometer marker are selected. These
intersections are the points on the radial at which measurements are to be made,
and are referred to subsequently as measuring locations. The elevation of each
measuring location should approach the elevation at the corresponding 3
kilometer marker as nearly as possible.
(2) Measurement procedure. All measurements must be made utilizing a receiving
94 F.C.C. 2d
196 Federal Communications Commission Reports
antenna designed for reception of the horizontally polarized signal component,
elevated 9 meters above the roadbed. At each measuring location, the following
procedure must be used:
0. * *
(ii) The antenna is elevated to a height of 9 meters.
* * * * *
(v) A mobile run of at least 30 meters is made, that is centered on the intersection
of the radial and the road, and the measured field strength is continuously
recorded on a chart recorder over the length of the run.
* * * * *
(vii) If, during the test conducted as described in paragraph (b)(2)(iii) of this
Section, the strongest signal is found to come from a direction other than from the
transmitter, after the mobile run prescribed in subparagraph (b)(2\v) of this
Section is concluded, additional measurements must be made in a “cluster” of at
least five fixed points. At each such point, the field strengths with the antenna
oriented toward the transmitter, and with the antenna oriented so as to receive the
strongest field, are measured and recorded. Generally, all points should be within
60 meters of the center point of the mobile run.
(viii) If overhead obstacles preclude a mobile run of at least 30 meters, a “cluster”
of five spot measurements may be made in lieu of this run. The first measurement
in the cluster is identified. Generally, the locations for other measurements must
be within 60 meters of the location of the first.
* * * * *
(0* * *
* * * * U
(2) Measurement procedure. All measurements must be made using a receiving
antenna designed for reception of the horizontally polarized signal component,
elevated 9 meters above ground level.
* . , . *
17. Section 73.316 is amended by revising the headnote and paragraph (e) to read as
follows:
§ 73.316 FM antenna systems.
* * * * *
(e) Applications proposing the use of FM transmitting antennas in the immediate
vicinity (i.e. 60 meters or less) of other FM or TV broadcast antennas must include a
showing as to the expected effect, if any, of such approximate operation.
* * * * *
18. Section 73.333 is amended by revising the introductory text, Figures 1 and la, and
deleting Figure 3 as follows:
$73.333 Engineering Charts.
This Section consists of the following Figures 1, la, and slider, 4, and 5 (Figure 3
deleted).
* * * * *
19. Section 73.504 is amended by revising the introduction of paragraph (c) to read as
follows:
94 FCC. 2d
FM Broadcast Stations 197
11
F(50,50) FM CHANNELS =o
oe: 1.5
10 uz = 2
a - 5
3 »
9 s
i
5 15
a z 20
e =
w = so
==
PARU = z so
F z Et
T E so
= ieee = == > A so
2 6
z +r ttt + T ”
> .o
> 5
»
w + 100
= + r — + 110
e T 7 120
CJ 130
o 3 140
z 150
= 160
z 170
+ 2 180
z 190
00
= 10
a 30
m4 230
gd
= HH
fa 290
R [300
aT
a > :
Tí 7 = R
-2 == z a -
30 50 100 500 1600
Transmitting Antenna Height in Meters
FCC 873.333 FIGURE 1 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 9 METERS
94 F.C.C. 2d
DISTANCE IN KILOMETERS
198
UY/M FOR 1 Kw ERP
FIELD STRENGTH IN DB ABOVE
FCC 573.333
Federal Communications Commission Reports
A
SESAZEZ ZZ
6 ==
==
s === i
at SU
= ZEP |)
Ñ
|
|
|
i
|
|
M
|
|
|
|
|
RE
-20 eS SSS R A |
Z TA eee
O O O ZA
= SSS See
i ES)
ee |
pe ee
=== A
|
:
|
i
|
= ==
=== ===
30 50 100 200 500 1000 1600
Transmitting Antenna Height in Meters
FIGURE la FM CHANNELS
ESTIMATED FIELD STRENGTH EXCEEDED AT 50 PERCENT
OF THE POTENTIAL RECEIVER LOCATIONS FOR AT LEAST 10 PERCENT
OF THE TIME AT A RECEIVING ANTENNA HEIGHT OF 9 METERS
94 F.C.C. 2d
ETERS
DISTANCE IN KILO
FM Broadcast Stations | 199
$ 73.504 Channel assignments under the U.S.A.-Mexico FM Broadcast Agreement.
* + * + *
(e) The minimum distance separations given in $ 73.207 apply to the following:
* + » * *
20. Section 73.506 is amended by revising the headnote and paragraphs (aX3) and (b),
and by adding new paragraph (c) to read as follows:
$ 73.506 Classes of Noncommercial Educational FM stations and channels.
(aj* * *
* * * * *
(3) Noncommercial educational stations with more than 0.01 kW transmitter
power output are classified Class A, B1, B, C2, C1, or C, depending on the effective
radiated power, antenna height above terrain, and the zone in which the station’s
transmitter is located, on the same basis as provided for in §§ 73.205, 73.206, and
73.211 for stations on the non-reserved FM channels.
(b) Any noncommercial educational station except Class D may be assigned to any of
the channels listed in § 73.501. Class D noncommercial educational FM stations
applied for or authorized prior to June 1, 1980, may continue to operate on their
authorized channels subject to the provisions of § 73.512.
21. Section 73.507 is amended by revising paragraph (c) and note to read as follows:
§ 73.507 Minimum distance separation between stations.
* * * * *
(cX1) Stations separated in frequency by 10.6 or 10.8 MHz (53 or 54 channels) from
allotments or assignments on non-reserved channels will not be authorized unless
they conform to the following separation table:
Required spacing
Class of stations: kilometers (miles)
AtoA.. 228 (5)
BtoA 16 (10)
B to B .24 (15)
Cto A .32 (20)
C to B .40 (25)
Cto C .48 (30)
(2) Under the United States-Mexican FM Broadcasting Agreement, for stations
and assignments differing in frequency by 10.6 to 10.8 MHz (53 or 54 channels), the
following separations apply to U.S. noncommercial educational FM allotments and
assignments and Mexican allotments or assignments in the border area.
Required spacing
Class of stations: kilometers (miles)
C to D .. .24 (15)
B to D .. .16 > (10)
Cto D 8 (5)
DtoD.. RE) (2)
Note. For purposes of this Section, Classes B1 and C2 will be considered Class B, and
Class C1 will be considered Class C until further notice.
22. Section 73.509 is amended by revising paragraph (e) to read as follows:
94 F.C.C. 2d
200 Federal Communications Commission Reports
§ 73.509 Protection from interference.
* * * * *
(e) No application for FM Channel 200 will be accepted if the requested facility
would cause interference to Channel 6 operations, including TV translators on this
channel. Such objectionable interference will be considered to exist whenever the 15
dBu contour of the proposal, based on the F(50,10) curves in $ 73.333 Figure la, would
overlap the 40 dBu contour of the television station, based on the F(50,50) curves in 8
73.333 Figure 1.
23. Section 73.511 is amended by revising paragraph (b) to read as follows:
$ 73.511 Power and antenna height requirements.
* * U * *
(b) On Channels 218, 219, and 220 specified in $ 73.501, no educational station will be
authorized with effective radiated power greater than that specified in $ 73.211(b)(1)
for the respective class of station, and the maximum effective radiated power
permissible shall also be subject to the provisions of $ 73.211(bX2).
23. Section 73.3573 is amended by revising paragraphs (aX1) and (c) as follows:
§ 73.3573 Processing FM broadcast and FM translator station applications.
(aj* * *
(1) In the first group are applications for new stations or for major changes in the
facilities of authorized stations. A major change for FM stations authorized under
this Part is any change in frequency, station location, or class of station; or, any
antenna location which would result in a change of 50% or more in the area within
the station's predicted 1 mV/m field strength contour. (A change in area is defined
as the sum of the area gained and the area lost as a percentage of the original area.)
For FM translator stations authorized under Part 74, it is any change in frequency
(output channel), primary stations, or authorized principal community or area.
However, the FOC may, within 15 days after the acceptance for filing of any other
application for modification of facilities, advise the applicant that such application is
considered to be one for a major change and therefore is subject to the provisions of
§§ 73,3580 and 1.1111 pertaining to major changes.
* . * * *
(e) If, upon examination, the FCC finds that the public interest, convenience and
necessity will be served by the granting of an application for FM broadcast facilities,
the same will be granted. If the FCC is unable to make such a finding and it appears
that a hearing may be required, the procedure given in $ 73.3593 will be followed.
* * U * *
Dissenting Statement of FCC Commissioner James H. Quello
In Re: FM Drop-Ins - Docket No. 80-90
I don’t believe the engineering record or the hypothetical need
developed in Docket 80-90 justifies the proposed widescale increase
in FM allotments.
This action would cause degraded service, turmoil and interfer-
ence for millions of existing listeners, contention and litigation
among applicants and further administrative burdens on a Mass
Media Bureau already overburdened with a huge backlog of AM-FM
and low power TV applications.
94 F.C.C. 2d
FM Broadcast Stations 201
I believe a wiser, more reasoned approach would be to present new
FM allotments on a case-by-case basis through waiver requests. This
would provide an opportunity to actually test the extent of interfer-
ence and overall public acceptance before risking an untested,
strongly contested, widescale increase and reallotment.
T lend considerable weight to the expert engineering study by A.
D. Ring which indicates a net loss in service would result in the
Commission’s proposals. I agree with the logic in the study that any
increase in FM availability would cause a significant detriment to
present listening. Also, I believe it is a rule of physics, not of this
Commission, that a new station causes interference far beyond the
boundaries of new service.
Tm concerned that the value of a strong secondary service now
enjoyed by millions of listeners is allotted a much lower priority than
the undocumented need for a new, frequently substandard, FM
service. I also believe FM stereo should be treated as a significant
state of the art improvement in basic service, rather than as a mere
expendable ancillary enhancement.
To the extent that the Commission has relied upon the “need” for
vastly increased FM allotments, I believe it has been misled. I have
seen nothing in the record which documents this alleged need
beyond some “wish lists” prepared on a hypothetical basis and
largely for purposes other than this Rulemaking.
The only rational public interest reason for embarking upon this
massive change in the Table of Allotments is to provide for better,
more diversified FM radio service to the American people. The fact
is, however, this revised scheme of allocation will merely provide
different service in many instances and reduced or deleted service in
others. As suggested before, it is axiomatic that for each new service
introduced, interference to existing service is also introduced. For
some listeners, their present stereo service will become monaural.
For others, their present monaural service will become further
degraded or disappear.
SEPARATE STATEMENT
OF
COMMISSIONER HENRY M. RIVERA
RE: Modification of FM Technical Rules to Increase the Avail-
ability of Broadcast Stations—BC Docket 80-90.
By this decision, the Commission has dramatically increased the
potential for local FM radio service to the American public and the
enhanced competition and diversity that increased service implies.
The Commission’s staff forecasts that many major cities, where
additional outlets were previously foreclosed, will now be eligible for
additional stations as a consequence of today’s rule changes. Many
communities in remote locations will now qualify for their first local
94 FCC. 2d
202 Federal Communications Commission Reports
service as well. All told, the Mass Media Bureau estimates that this
decision will make it possible to satisfy as much as 57 percent of the
expressed demand for additional FM radio stations; under the old
allocation structure, just seven percent of this demand could have
been accommodated. More specifically, of the 1000 communities
studied, additional stations can now be assigned to approximately 49
percent which have daytime-only AM service and 31 percent of those
which have no local service. This action will also serve the interests
of 40 percent of the communities said to need additional minority-
owned stations, as well as the interests of 26 percent of the locations
desiring additional public radio stations.
The public interest benefits of our decision are clear and substan-
tial. Still, because the paramount objective of this proceeding has
been to secure additional service, it was imperative for the Commis-
sion to ensure that the proposed technical changes to allow
additional FM stations would not significantly degrade the FM
service overall. With one exception (the uniform protected contour
proposal), the Commission has concluded that the addition of new
FM stations will not detract materially from the technical integrity
of existing FM service, and I believe our determinations in this
regard are both responsible and consistent with sound engineering
principles.
The Commission has decided that, rather than entertaining
random requests for the new channels made possible by these rule
changes, most of these new channels should be allotted in one
omnibus proceeding. Our decision to amend the FM Table of
Allotments accordingly is especially wise. The licensing of additional
FM stations will now proceed in a smooth and orderly fashion, which
will minimize potential delays and maximize the expeditious deliv-
ery of new FM service consistent with FCC resources.
While I would have preferred more expeditious consideration of
these proposals, I am delighted that we have finally and affirmative-
ly acted upon them. And, although I wish resource limitations did
not require postponing the effective date of our action until Fiscal
Year 1984, we will still be moving forward during the intervening
four months with preparation of the rulemaking that is required for
the public to apply for stations under the newly adopted technical
rules.
In sum, this Report and Order marks a renewed Commission
commitment to the principles of diversity and competition—princi-
ples which must be the basis for the integrity and credibility of our
ongoing broadcast deregulatory efforts. The public interest is well-
served by this decision in and of itself, and I am especially pleased to
see this long-awaited action taken at last.
94 F.C.C. 2d