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AGBs salle
— DURS NTU SIO EIN
FEDERAL COMMUNICATIONS COMMISSION
OFFICE OF CHIEF ENGINEER
RESEARCH AND STANDARDS DIVISION
REPORT NO. RS75-08
FM BROADCAST CHANNEL FREQUENCY SPACING
By
Harry Fine
and
George L. Sharp
WASHINGTON, D. C. 20554
December 1975
SUMMARY
This report studies the effect of reducing the adjacent channel
frequency offset from the presently used 200 kHz to 150 kHz and
to 100 kHz. The analysis shows quite conclusively that both
the 100 kHz offset, with a receiver filter, and the 150 kHz off-
set (no filter) are more efficient in population and area coverage
efficiency than the 200 kHz offset for both stereophonic and
monaural operation. The 100 kHz offset, with filter, gives
about twice the improvement that the 150 kHz offset offers.
However, the 100 kHz offset advantage is contingent upon the
use of a low pass filter following the demodulator in the stereo-
phonic receiver, without which the 100 kHz offset is somewhat
worse than the 200 kHz offset. For lack of protection criteria
the effect of reducing the frequency offset upon SCA and quadra-
phonic operation could not be evaluated.
FM BROADCAST CHANNEL FREQUENCY SPACING
Introduction
The total spectrum bandwidth available for assignment to FM broad-
cast stations is limited and in some areas quite congested. It is
therefore desirable that station assignments be made in the most
efficient manner. The present study was undertaken to determine
the relative efficiency of adjacent channel FM assignments at 100
kHz or 150 kHz separations as contrasted with the present assign-
ment plan which uses 200 kHz separations. The area coverage effi-
ciencies, service ranges and available number of station assignments
are compared for both monaural and stereophonic operation. The
technical station operating parameters, such as emission bandwidth,
frequency deviation, etc., are assumed to be unchanged. The study
does not include the effects of Subsidiary Communications Authori-
zations (SCA) and quadraphonic operations.
A simplified equilateral triangular cochannel lattice assignment
plan has been assumed for thys study as the most efficient station
assignment configuration.——/ Admittedly, such a regular configuration
is not representative of the true physical distribution of the dis-
tances between population centers, nor are the transmitting antenna
heights uniform nor the radiated powers all the same. In effect,
all the station parameters, as well as the physical and propagation
parameters, are statistically variable. The net effect is to increase
substantially the overall standard deviations in the results, which
means that because of this variability, the actual performance could
differ greatly from what these idealized computations predict. Never-
theless, the comparisons and trends indicated in this study should
be sufficient for the ο. of station assignment policy.
Thus, the Ad Hoc Committe l/used substantially the same techniques
for its TV studies and noted (P 5 of Vol. II), "Even though the
present data may be inadecuate for meking an accurate prediction
of the eventual total service, it should be noted that comparisons
of national services which differ because of different allocation
policies can, nevertheless, be made with a high degree of accuracy.
For example, useful comparisons can be made between the results to
be expected with different antenna heights, powers, station separations,
etc."
Service Concepts and Criteria
Since the wanted and interfering signals in the FM frequency range
(88-108 MHz) vary both in time and from location to location, it is
useful to describe the service in statistical terminology, using
the same concepts of service that have been developed for TV broad-
που Thus, the service at any location is considered to be
732
Should the 100 kHz adjacent channel offset operation be adopted in the
U.8., there would then be the economic incentive to mass-produce such
filters at a reasonable cost especially in view of the increasing use
of integrated circuits. Therefore, the emphasis in this report has
been upon the use of such low pass filters in the stereophonic re-
ceivers for the 100 kHz offset. The problem of retrofitting existing
stereo receivers which do not have filters, is beyond the scope of
this report.
For this study the following values of minimum usable field strength
levels were assumed to compute service in the presence of noise only:
Monaural : 24 dBa
Stereophonic : 36 dBu.
The monophonic value was derived by applying а 10 dB fading тасъог1/
to the 50 uy/m median field strength which has often been used by the
F.C.C. for rural service. And, the stereophonic value was tasn obtained
by adding 12 dB to the monophonic value, as suggested by CCIR=/. Other
numbers may be substituted for the above but the computed trends will
not be changed, except perhaps at the greater cochannel spacings. Ве-
cause of the multiple interference for a full lattice, the noise is
relatively unimportant except for a combination of wide spacings and
low radiated power.
The receiving antenna discrimination pattern of Fig. 2 was used for
servi ge computations. It is similar to that of CCIR Recommendation
119,2’ except that the discrimination increases with the square of
the secant of the angle fro: the main beam rather than the logarithmic
trend of CCIR. The secant squared variation is believed to be more
typical for receiving antennas.
A triangular lattice network of cochannei stctions with stations
located at the vertices of the equilateral triangles provides the
most efficient area coverage for a channel, as outlined in Reference 4.
Consequently, equilateral triangie cochannel networks were employed
in this study. The edjacent channel stations were located as erfi-
ciently as possible within the equilateral cocrannel triangles, using
the assignment techniques developed in References 5 and б. The assign-
ment method is described in more detail in Annex A.
Figs. 3, 4 and 5 illustrate the most efficient regular assignment plans
for FM broadcast stations with minimum adjecent channel carrier offsets
of 200, 150 end 100 kHz, respectively. Only the basic parellelograms,
consisting of two adjacent equilateral cochannel triangles, are shown.
The numbers at the various station locations denote ihe multiples of
the minimum permissible adjacent channel frequency offset. The
negative numbers indicate that the station carrier frequency is lower
than the reference carrier frequency. Thus, in Fiz. В the station at
A ш
The number of station assignments available, compared to that at a
200 kHz offset, is computed from
(3) = 2
Nat Моо = (Sago/SAr) (200748)
where
p
~
н
the minimur. frequency offset, іп kHz
the numoer of frequency offsets before a channel
(4) may be repeated at a given location, Гог а freauency
offset of Af
г
>
--
Ш
the cociannel spacing for a frequency otfsct сг Af,
s
Af in km
The service ranzes and lattice efficiencies were computed under the
assumed lattice configurations of Figs. 3, 4 and 5, using ure multiple
interference computation techniques of Annex 2 for the combinations
of transmitting antenna height and radiated power given elow in Table 1,
Table 1
Curve Power, kw Transmitting Antenna
—— meg Antenna
Height, ft
A 50 2000
B 50 1000
ς 50 500
D 10 500
E 3 300
Discussion .
Using the parameters listed in Table 1, service contours and efficiencies
were computed for 200 kHz, 150 kHz, and 100 kHz, without filter, offsets
for both monaural and stereophonic operations. In addition, the
service contours and efficiencies were also computed for the 100 kHz
stereophonic operation, with filter. These are plotted versus
ege
a single criterion but rather on a joint weighted comparison of
the several criteria. So long as the service radius per station
is great enough to cover the required area and to provide for
economic viability, it becomes a relatively unimportant parameter
to the allocation engineer. Thus, the main attention should be
focussed upon the overall area efficiency and the relative number
of station assignments - i.e. the area and the population coverage.
No attempt will be made here to assess the relative importance of
the overall area efficiency and the relative number of available
station assignments, other than to note that they are both quite
important. Further, it is believed that stereophonic coverage for
FM is much more important than monaural coverage.
For purposes of comparison, Table 2 was derived from Fig. 6 through
19. At the cochannel spacings for which the maximum area efficiencies,
the cochannel spacings at which they occur, the station service radii
for these spacings, and the relative number of station assignments
available both for monaural and stereophonic operation. It is
noted that both the relative number of assignments and the relative
efficiency of operation increase as the frequency offset is decreased,
except that the 100 kHz operation, without filter, is the least
efficient mode of operation. On the other hand, the station service
range decreases somewhat as the offset is reduced. Thus, for a full
lattice of Class B FM stations - 50kw at 500 ft.the stereo area
efficiency at 100 kHz offset, with filter, is 23% greater than with
the 200 kHz offset and the available number of station assignments
is 51% greater. The improvement for 150 kHz offset as compared to
the 200 kHz offset runs about half that for the 100 kHz offset,
with filter. A comparable improvement is available for all height-
power combinations used in the study. Unquestionably, the improvement
available in reducing the offset below 200 kHz is substantial. For
monaural operation the trends are similar but the improvements in
"overall area" efficiency and available number of assignments, as
the frequency offset is reduced, are even greater than for stereo
operation.
The comparisons between the different offsets are made from a some-
what different point of view in Table 3, which was also compiled
from Figs. 6 through 19. In this table, the stereophonic service
radius is kept constant, the cochannel spacings being varied to
provide the desired service radius. Thus, if the service radius is
set to provide a given service area per station on the basis that such
à service radius is required to provide station economic viability,
the comparison still shows that the 100 kHz offset, with receiver
filter, is the most efficient operation and that the 100 kHz offset,
without filter, is the least efficient. Again, the 150 KHz offset
-8A-
It should also be emphasized that our cities and towns are not
arranged geographically in nice regular lattices, so that the
full efficiencies of the reduced offsets could not be realized
in practise. However, the relative trends and comparative
advantages would be realizeable, so that the results of this
report should be useful in assessing the costs for continuing
with the present 200 kHz offset.
Conclusions
The analysis shows conclusively that from a technical point of
view both the 100 kHz offset, with a low pass receiver filter
after the second demodulator, and the 150 kHz offset are more
efficient than the presently used 200 kHz offset, both in overall
area coverage efficiency and in the available number of station
assignments - i.e. in area and population coverage. The 100
kHz offset, with filter, shows about twice the improvement that
the 150 kHz offset offers. However, the 100 kHz offset advantage
would be contingent upon the use of receiver filters, without which
the efficiency would be a little worse than that for the 200 kHz
plan. Also, since there already exists a viable FM system with
a 200 kHz offset,any reassessment would have to consider other
factors, such as the costs of changing station frequencies, the
costs for incorporating the receiver filters for 100 kHz offset,
reduced SCA service range, and reduced quadraphonic service range.
>= κ,
Annex A
REGULAR EFFICIENT ASSIGNMENT PLANS
The assignment plans were designed along the concepts developed in
References 5 and 6 for the efficient distribution of adjacent channel
stations within the cochannel lattice. The technique not only
provides an efficient assignment plan but also gives a systematic
method of locating the stations in a regular order, with each
station receiving equal cochannel and adjacent channel interference
protection. The practical application of the technique for locating
the adjacent channel stations within the basic cochannel parallelogram
of two adjacent equilateral cochannel triangles is relatively simple.
The basic cochannel parallelogram is subdivided into N2 equal smaller
parallelograms, as shown in Figs. 3, 4 and 5, by dividing the sides of
the basic parallelogram into N equal parts and drawing a grid of
parallel lines through the dividing points. №1 is the number of
adjacent channel stations. And, N is also the number of frequency
offsets before a channel may be repeated at a given location. The
stations are ordered in multiples of the minimum offset frequency А,
so that m Д f represents the carrier frequency offset. Using the
lower left corner of the basic cochannel parallelogram as the zero
of a graph plot, the adjacent channel stations are located in
regular order at points
(A1) (X, Y) = (mA, mB) теш =ї ees |
m Af = carrier frequency offset, in kHz
Af - minimum frequency offset, in kHz
When mA or mB exceeds N or a multiple of N, the remainder is used
for plotting the stations within the basic parallelogram. Thus,
for plotting purposes
(A2) mA -aN = mA -bN arbe 0,1,2:.
21,2
In the above, a may be different from b.
Various values of A and B are tried and the best combination with
respect to interference is selected by observation. The choice is
not difficult and can usually be made quite readily, since those
adjacent channel combinations are known, which are the most susceptible
to interference. Further, a number of combinations of parameters A
and B give essentialiy the same lattice, rotated about the center axis.
- 11 -
Annex B
COMPUTATION OF SERVICE AND INTERFERENCE
The method used for the computation of station service in the
presence of both single and multiple sources of interference will
be developed in this Annex. It is a combination of two methods
described in Volume II of the Ad Hoc Report .2/
The field strength from a station may be described, approximately
as a two dimensional lognormal (in p v/m) or normal (in ави)
distribution, in order to account for the variability with time
and from location to location. Thus, the field strength may be
described by:
(B1) F(L,T) = F(50,50) + MEL * Ya dBu
where
F(L,T) = the level of field strength exceeded for
T percent of the time in at least L percent
of the locations, in dBu
F(50,50) = field strength median in both time and
location, in dBu
(B2)
στ = standard deviation for time variability, in dB
с = standard deviation for location variability,
L :
in dB
X(T), Y(L) = standard variates for the normal distribution
In (Bl), F(50,50) and ©. may be obtained from FCC Report R6602,2/
where T
(B3) от = F(50,10) - F(50,50) dB
1.282
From Volume I of the Ad Hoc Reportl/is obtained the value of
(84) "c 8.3 dB
And the standard Gaussian variate, X(T) or Y(L), is tabulated in
many statistical textbooks. It is also plotted in Figure 30 of
Reference 8. š
- 13 -
are added powerwise statistically to give a resultant required
wanted field which is also constant with time and has a variabilility
with location which is assumed to be lognormal. “his technique for
combining multiple interferences is good so long as the Fari have
about the same standard deviations for their location distributions.
It is therefore used to combine all the interferences except noise
which is assumed not to vary from location to location. To compute
the resultant lognormal distribution from the various interference
sources (except noise), the first two central moments for the individ-
ual location distributions Far; are added.
a= ехр(о;2/2) Ση watts
p= [ехр(о;®) = ) expla?) ХР? warts?
(вв) 4 9,7 0.230269 =1.90655 nepers
R = ipfe 10 watts
а= 8.3 a
The resultant median and normal standard deviation are then computed
from:
αι” = in[ {+ μκ/αξ] nepers?
(59) 4 Py = аехр(-<, 2/2) — watts
k = 0.468 (for zero correlation)
The factor К was found empirically to improve the lognormal approxima-
tion for the resultant. More details on this lognormal approximation
for the resultant distribution of the required wanted signal may be
found in Volume II of Reference 1. The values of (B9) may be converted
to the more useful units:
σι dr = 4.3429 Sar ав
(B10)
Е, (50,50) = 10 log Ry,
ави
- 15-
BIBLIOGRAPHY
"Report of the Ad Hoc Committee for the Evaluation of the Radio
Propagation Factors Concerning the TV and FM Broadcasting Services
in the Frequency Range Between 50 and 250 Mc", Volume I, (May 31,
1949) and Volume II (July 7, 1950)
International Radio Consultative Committee (CCIR), XII th Plenary
Assembly, New Delhi, 1970, Volume V, Part 1, "Broadcasting Service
(Sound) "
. International Radio Consultative Committee (CCIR), XII th Plenary
Assembly, New Delhi, 1970, Volume V, Part 2, "Broadcasting Service (TV)"
K.A. Norton and H. Fine; "A Study of Methods for the Efficient
Allocation of Radio Frequencies to Broadcasting Services Operating
in the Range Above 50 Mc"; Reference E to the "Report of the Ad Hoc
Committee for the Evaluation of the Radio Propagation Factors Concerning
the TV and FM Broadcasting Services in the Frequency Range Between 50 and
250 Mc", Report CRPL -4-5, August 1, 1949.
H. Eden, H.W. Fastert and K.H. Kaltbeitzer, "Methods for Planning Optimum
TV Networks for Bands IV and V", E. B. U. Review No. 59-A, (February, 1960)
H.W. Fastert "The Mathematical Theory Underlying the Planning of Trans-
mitter Networks", E. B. U. Review No. 60, (April, 1960)
J. Damelin, W.A. Daniel, H. Fine, G.V. Waldo, "Development of VHF and
UHF Propagation Curves for TV and FM Broadcasting" FCC Report No. R 6602
(September 1966)
H.Fine "A Further Analysis of TASO Panel 6 Data on Signal to Inter-
Radios and Their Application to Description of TV Service" FCC ТЕК
Report No. 5.1.2 (April, 1960)
ES LE
Table 2
Comparison Under Conditions of Maximum Efficiency
2000 ft. 1000 ft. 500 ft. 500 ft. 300 ft
Monaural 50 kw 50 kw 50 kw 10 kw 3 kw
$100 (mi) 230 200 205 200 195
E100 (%) 22.8 21.5 19.6 19.5 16.7
R100 (mi) 41.0 34.5 33.3 32.7 29.3
N100/N200 1.91 2.00 2.10 1.90 1.70
Е100/Е200 1.25 1.28 1.32 1.32 1.37
5150 (mi) 190 200 205 200 185
E150 (%) 20.8 20.0 18.2 18.2 15.2
8150 (mi) 39.5 38.7 39.6 38.7 32.7
N150/N200 1.87 1.33 1.40 1.27 1.26
E150/E200 1.14 1.19 1.22 1.23 1.25
5200 (mi) 225 200 210 195 180
E200 (%) 18.2 16.8 14.9 14.8 12.2
R200 (mi) 50.5 43.0 42.5 39.5 33.0
Stereophonic
$100 (mi) 285 265 265 245 245
E100f (%) 18.9 16.7 14.5 13.5 10.2
R100f (mi) 46.0 40.1 37.3 33.5 25.4
N100f/N200 1.42 1-51 1.51 1.40 1.33
Е100#/Е200 1.19 1:33 1.23 1.24 1.34
$1005 (mi) 350 345 345 305 280
ElOOu (5) 14.7 12.6 10.6 9.5 6.9
RlOOu (mi) 50.0 45.0 41.0 35.0 27.2
N100u/N200 0.94 0.89 0.89 0.90 1.02
E100u/E200 0.92 0.91 0.90 0.87 0.91
5150 (mi) 250 240 245 215 205
E150 (%) 16.9 15.3 13.0 12.1 8.9
R150 (mi) 47.0 42.8 40.0 34.0 27.2
N150/N200 1.23 1.22 1.18 1.21 1.27
E150/E200 1.06 1.10 1.10 1.11 1.17
5200 (mi) 240 230 230 205 200
E200 (5) 15.9 13.9 11.8 10.9 7.6
R200 (mi) 50.5 45.0 41.3 35.5 29.0
= E =
Table 3 (Continued)
Comparison Under Conditions of Constant Service Radius
Stereophonic Monaural
Rstereo (mi) АЕ Sst Est Nae ΕΔε Emono Rmono EA:
(kHz) (mi) G) Nooo E200 (5) (mi) E200
50 kw, 500 ft.
100# 390 11.9 1.08 1.12 15.5 57.0 1.15
50 1004 442 9.0 0.84 0.85 14.0 61.5 1.04
150 330 11.2 1.01 1.06 15.1 58.2 1.12
200 287 10.6 Р es I3.5 55.0 =
100Е 287 14.2 1.20 1.20 18.3 45.7 1.24
40 1000 337 10.5 0.87 0.90 17.1 51.8 1.16
150 243 13.0 1.11 1.10 17.7 46.5 1.20
200 222 11.8 — -- 14.8 45.0 --
100# 218 13.9 1.30 1.37 19.5 35.5 1.34
зо 100u 264 9.4 0.89 0.90 18.8 42.5 1.29
150 188 12.0 1.17 1.15 18.2 36.3 1.25
200 i76 10.4 == I 14.6 35.0 ==
100# 160 11.0 1.49 1.47 18.7 26.0 1.43
20 100u 202 7.2 0.93 0.96 19.5 33.0 1.49
150 145 9.0 1.21 1.20 16.5 26.5 1.26
200 138 7.5 == == 13.1 26.0 =
10 kw, 500 ft.
100Ε 303 12.7 1.20 1.21 17.7 47.0 1.25
40 100u 333 9. 0.89 0.89 15.6 51.7 1.10
150 257 11.7 1.11 1.11 16.7 47.8 1.18
200 235 10.5 -- -- 14.2 46.5 za
100f 220 13.9 1.31 1.37 19.6 36.0 1.34
30 100u 267 9.2 0.89 0.88 18.5 42.5 1.27
150 192 11.8 1.15 1.13 18.1 37.2 1.24
200 178 10.4 == “= 14.6 35.7 =
100Е 162 11.2 1.45 1.47 18.7 26.0 1.43
20 100u 202 7.2 0.93 0.95 19.5 33.0 1.49
150 146 9.2 1.19 1.21 16.5 27.0 1.26
200 138 7.6 == ae 13.1 27.0 ==
3 kw, 300 ft.
100f 258 9.8 1.30 1.29 15.4 37.8 1.29
30 100u 312 6.8 0.89 0.89 13.5 42.7 1.13
150 224 8.6 1.15 1.13 14.5 39.0 1.22
200 208 7.6 = = 11.9 37.7 ==
100 177 9.5 1.42 1.48 16.4 26.5 1.44
20 100u 220 6.0 0.92 0.94 16.4 33.0 1.44
150 157 7.6 1.20 1.19 14.6 27.3 1.28
200 149 6.4 => кес 11.4 26.8 ==
100Е 113 1:57 1.61 12.7 14.5 1.63
10 100u 142 0.99 1.03 14.8 19.6 1.90
150 103 1.26 1.22 10.2 14.3 ЖТ
200 lan з.б == == T.R 14.7 =
50
30
m
o
PROTECTION RATIO (dB)
o
o
-10
-20
-30
-40
= 20: =
Figure 1
REQUIRED SIGNAL TO INTERFERENCE RATIOS
vs.
CARRIER FREQUENCY DIFFERENCE
@ STEREOPHONIC (FILTERED RECEIVER)
О STEREOPHONIC (UNFILTERED RECEIVER)
4 MONAURAL
206 300
CARRIER FREQUENCY OFFSET (kHz)
abet 1 “Charis
t
° ο ο ο ο
ЖЕ ОЖ Ж
Figure 2
RECEIVING FM ANTENNA GAIN PATTERN
-20 log sec@ ав; 05%6$59.9°
-6 ; 8259.99
3
е
^R
š
š
g
E
н
8
B
Е
Е
š:
Е
š
А.
= 23
FM STATION NETWORK LATTICE
(150 kHz Minimum Difference Between Channels)
Numbers 0-5 refer to Frequency Difference in 150 kHz multiples, positive
being above the desired channel and negative being below the desired channel.
Equilateral triangles are formed by any 3 co-channel stations.
Carrier Difference S/I Protection Ratio in dB
m Stereophonic
Multiple in kHz Monaural Unfiltered
o 0 28 36
1 150 8 15
2 300 -7 -7
9 450 -25 -25
4 600 -40 -40
5 720 Е A
Figure 4
DISTANCE TO SERVICE CONTOUR - KILOMETERS
=
=
о
=.
сә
e
`D
©
со
©
-ᾱ
©
o
e
ul
C
>
e
Ww
[7]
гу
°
=
>
100
CO-CHANNEL STATION SPACING - MILES
100 200 300 400
50 kw, 2000 ft
50 kW, 1000 ft
50 kW, 500 ft
10 kW, 500 ft
3 kW, 300 ft
Figure 6
DISTANCE TO THE SERVICE CONTOUR
vs.
CO-CHANNEL STATION SPACING
Hy = 30 ft Р, and Hy as specified
200 kHz Offset Plan
Monaural Broadcasting
200 300 400 300 600
CO-CHANNEL STATION SPACING - КНОМЕТЕВ$
SATIW - UNOLNOO SOIAWSS OL AONVILSIG
-GZ-
e
Ф
- KILOMETERS
°
o
w
©
DISTANCE TO SERVICE CONTOUR
гы
e
m
e
CO-CHANNEL STATION SPACING - MILES
100 200 300
P and H
t t
400
50 kW, 2000 ft
50 kW, 1000 ft
50 kW, 500 ft
10 kW, 500 ft
3kW, 300 ft
Figure 8
DISTANCE TO THE SERVICE CONTOUR
vs.
CO-CHANNEL STATION SPACING
H, = 30 ft
_ 100 kHz Offset Plan
100 200 300 400 500
CO-CHANNEL STATION SPACING - KILOMETERS
600
Pt and H, as specified
Monaural Broadcasting
SW'IDIWN - YNOLNOD ΠΌΟΙΛῈΞΠΘ OL HONV.LSIG
-10-
CO-CHANNEL STATION SPACING - MILES
ο 100 200 300 400
Р, and H
`D
e
t
- 50 kW, 2000 ft
- 50 kW, 1000 ft
- 50 kW, 500 ft
- 10 kW, 500 ft
70 : - 3kW, 300 ft
со
°
ul
e
Figure 10
"n
о
EM M — DISTANCE TO THE SERVICE CONTOUR
30 : | 7/4 vs.
CO-CHANNEL STATION SPACING
20 р Hp = 30 ft Pt and H; as specified
DISTANCE TO SERVICE CONTOUR - KILOMETERS.
0 100 200 300 400 500 600
CO-CHANNEL STATION SPACING - KILOMETERS
150 kHz Offset Plan Stereophonic Broadcasting
SATIN - UNOLNOO ЧОТАЧЯ$ OL ADNVISIC
- 62 -
110
fast
e
©
- KILOMETERS
> со ο
© © ©
o
о
> у
о о
DISTANCE TO SERVICE CONTOUR
N
©
10
CO-CHANNEL STATION SPACING - MILES
100 200 300 400
100
50 kW, 2000
50 kW, 1000
50 kW, 500
10 kW, 500
3kW, 300
^ Figure 12 `
‘DISTANCE TO THE SERVICE CONTOUR
vs.
CO-CHANNEL STATION SPACING
H, = 30 ft Р, апа н, as specified
.. 100 kHz Offset Plan Stereophonic Broadcasting
(with Receiver Filter)
200 300 400 500 600 700
CO-CHANNEL STATION SPACING - KILOMETERS
70
SATIN ΠΠΟΙΝΟΟ ΠΟΙΛΗΠ5 OL SONV.LSIG
- [E -
EFFICIENCY - PERCENT
249
CO-CHANNEL STATION SPACING - MILES
100 200 300
Р, and Hy
50 kW, 2000 ft
50 kW, 1000 ft
50 kW, 500 ft
10 kW, 500 ft
3 kW, 300 ft
100
CO-C
Figure 14
FM STATION ALLOCATION EFFICIENCY
vs.
CO-CHANNEL STATION SPACING
Finite Power
——— Infinite Power
H, = 30 ft P, and H, as specified
150 kHzOffset Plan Monaural Broadcasting
i | '
| | i :
!
200 300 400 500
HANNEL STATION SPACING - KILOMETERS
400
- €€ -
600
EFFICIENCY - PERCENT
24
22
20
18
=
о
CO-CHANNEL STATION SPACING
100 200
Figure 16
FM STATION ALLOCATION EFFICIENCY
cCoO- CHANNEL STATION SPACING
Finite Power
——— Infinite Power
Hy = 30 ft P, and Н; as specified
200 kHz Offset Plan Stereophonic Broadcasting
Py and Ht
50 kW, 2000 ft
50 kW, 1000 ft
50 kW, 500 ft
10 kW, 500 ft
3 kW, 300 ft
100 200 300 400
CO-CHANNEL STATION SPACING - KILOMETERS
1000 ft
ee 2
- SẸ -
CO-CHANNEL STATION SPACING - MILES
100 š 200
24 о т | 300 400
22 - Figure 18
FM STATION ALLOCATION EFFICIENCY
ув.
2p CO-CHANNEL STATION SPACING
Finite Power
18 ——— Infinite Power
Hy, = 30 ft P, and Н, as specified
16 — 100 kHz Offset Plan Stereophonic Broadcasting
m : (no Receiver Filter)
O
14 ση NN m 23 " í Е ===
f. i |
' ! '
12 iS πμ URS DEREN ЕЯ e
Ὁ ан | | es
9 P. an t i
810 - 50 kW, 2000 ft
9 - 50 kW, 1000 ft
fy - 50 kW, 500 ft
ἃ 9 - 10 kW, 500 ft
- 3kW, 300 ft
6 uut | É 4
4
2
0
0 100 200 300 400 500 600
CO-CHANNEL STATION SPACING - KILOMETERS
EREOPHONIC SERVICE CONTOUR - KILOMETERS
TOST
DISTANCE
=
k
©
[un
e
e
80r
тор
60
50
40
30
20
10
e
[ο 30 ft P, and H, as specified
DISTANCE TO MONAURAL SERVICE CONTOUR - MILES
10 20 30
Figure 20
STEREOPHONIC SERVICE RANGE
vs.
MONAURAL SERVICE RANGE
P+ and н;
50 kW, 2000 ft
50 kW, 1000 ft
50 kW, 500 ft
10 kW, 500 ft
3 kW, 300 ft
Offset Plans
100 kHz Plan, Filtered Receiver
150 kHz Plan, Unfiltered Receiver
200 kHz Plan, Unfiltered Receiver
100 kHz Plan, Unfiltered Receiver
20 30 40 50 60 70 80 90 100 10 120 130
DISTANCE TO MONAURAL SERVICE CONTOUR - KILOMETERS
140
- UNOLNOD ADIAUAS DINOHdMOAYALS OL ADNVALSIC
SATIN
- 6£ -