CHAPTER 1
Definitions
The following definitions supplement those contained in the International Telecommunication
Convention and in the Radio Regulations.
1.1 Coverage area
The area within which the field strength of the wanted transmitter is equal to or
greater than the usable field strength.
In this area the protection against interference is provided for 99% of time.
Note - The field strength of the wanted transmitter is derived from the propagation curve
relating to 50% of locations and for 50% of time.
1.2 Service area
The part of the coverage area in which the administration has the right to demand
that the agreed protection conditions be provided.
1.3 Usable field strength (Eu)
Minimum value of the field strength necessary to permit a desired reception quality,
under specified receiving conditions, in the presence of natural and man-made noise
and interference, either in an existing situation or as determined by agreements or
frequency plans.
Note 1 - The desired quality is determined in particular by the protection ratio against
noise and interference and, in the case of fluctuating noise or interference, by the
percentage of time during which the required quality must be ensured.
Note 2 - The receiving conditions include, amongst others:
- the type of transmission and frequency band used;
- the receiving equipment characteristics (antenna gain, receiver characteristics,
siting);
- receiver operating conditions, particularly the geographical zone, the time and
the season, or if the receiver is mobile, the local variations of the field strength
due to propagation effects.
Note 3 - The usable field strength can be calculated by the simplified multiplication method, or the power sum method. For the application of the Article 4 procedure, the simplified multiplication method
is used.
1.4 Nuisance field
The field strength of the interfering transmitter (at its pertinent e.r.p.) modified
by the relevant protection ratio.
CHAPTER 2
Propagation
2.1 Propagation data for the VHF broadcasting service
2.1.1 General
The propagation data given in this chapter were used for the planning of the broadcasting
service. They relate field strength to path length and the effective transmitting
antenna height. They represent the field strength exceeded at 50% of locations for
50% and 1 % of the time and apply to both horizontal and vertical polarization.
The data are given for various types of areas and climates, namely, land, cold sea,
warm sea and areas subject to extreme super-refractivity. The definition of these
categories has to be based on statistical data; it is thus to a certain extent arbitrary,
but experience indicates that the following distinctions are appropriate for the application
of the data set out in this chapter.
Cold sea
Seas, oceans and other substantial bodies of water at latitudes greater than 23.5°
North or South, but excluding the Mediterranean, the Black Sea, the Red Sea and the
area extending from the Shatt-al-Arab to and including the Gulf of Oman.
Warm sea
Seas, oceans and other substantial bodies of water at latitudes less than 23.5° North
or South, including the Mediterranean and the Black Sea.
Area of extreme super-refractivity
Seas, oceans and other substantial bodies of water in the area extending from the
Shatt-al-Arab to and including the Gulf of Oman.
Note - In bilateral and multilateral negotiations during the Conference, some administrations
in the Eastern Mediterranean area (East of 30° E) used the criteria described in section
2.3, for the application of the 1 % time curves, the sea area was assumed to include
also a coastal strip extending up to 50 km inland and for the Nile delta region (from
30° East to 32° East) a coastal strip extending up to 200 km inland.
2.1.2 Area of extreme super-refractivity
2.1.2.1 Oversea paths
For oversea path calculations for 50% of the time, Figure 2.2 was used. For the application
of the 1 % time curves, the sea area includes also a coastal strip extending up to
50 km inland.
For oversea paths in the area from the Shatt-al-Arab up to and including the Gulf
of Oman, calculations for propagation occurring for 1 % of the time were based on
the following formulae:
E = 106.9 - 20 log d for 10 ≤ d ≤ 400
E= 78.9- 0.06 d for d > 400
where
d = path length in km,
E = field strength in dB (μV/m).
2.1.2.2 Overland paths
For overland path calculations for 50% of the time, Figure 2.1 was used. For overland
path calculations for 1 % of the time, Figure 2.3 was used, but any coastal strip
as defined in section 2.1.2.1 was treated as sea.
2.1.2.3 Mixed paths
For both 1% and 50% of the time, mixed paths were evaluated according to the procedure
set out in section 2.1.3.5.
2.1.3 Application of the curves
2.1.3.1 Time variability
The field-strength values given in Figures 2.1 to 2.5, are those exceeded for 50%
and 1 % of the time. They are expressed in decibels relative to 1 μV/m and correspond
to an effective radiated power of 1 kW.
The 50% time curves were used for the determination of coverage areas. The 50% and
1% time curves were used for interference calculations for steady and tropospheric
interference respectively.
2.1.3.2 Effective transmitter antenna height
The effective height of the transmitting antenna, h1, is defined as its height over the average ground level between distances of 3 km
and 15 km from the transmitter in the direction of the receiver. The height of the
receiving antenna, h2, was assumed to be 10 m above ground level.
The curves given in Figures 2.1 to 2.5 correspond to effective transmitter antenna
heights, h1, from 37.5 to 1200 metres.
For effective antenna heights, h1, of 20 m and 10 m, additional curves can be derived from the 37.5 m curve by applying
correction factors of - 5dB and - 11 dB for distances up to 25 km, and 0 dB in both
cases for distances in excess of 250 km, with linear interpolation for intermediate
distances. For effective transmitter antenna heights, h1, of less than 10 m, the values derived for 10 m are used.
2.1.3.3 Location variability
The curves given are representative of 50% of locations, the percentage which was
used for planning purposes.
2.1.3.4 Terrain irregularity correction
The curves for propagation overland refer to the kind of irregular rolling terrain
found in many parts of Region 1. No terrain irregularity correction was taken into
account in drawing up the Plan.
Note - In bilateral or multilateral coordinations during the Conference, some administrations
took account of actual path profiles. This method may also be used for coordination
after the Conference.
2.1.3.5 Mixed land/sea path calculations
When the propagation path is partially over land and partially over sea, the following
method is used for interpolation between the appropriate land and sea curves.
EL,t: field strength for land path equal in length to the mixed path for t% of the time,
ES,t: field strength for sea path equal in length to the mixed path for t% of the time,
EM,t: field strength for mixed path for t% of the time,
ds : length of sea path,
dT : length of total path.
The field strength for the mixed path(EM,t) is then determined by using the formula:
In the calculations of mixed paths, a computerized approximation of the coastline
was employed. It should be borne in mind that in some cases this may give rise to
certain inaccuracies when compared to calculations based on the actual coastline.
2.2 Propagation data for the aeronautical radionavigation service
The compatibility calculations are based on free space propagation conditions. In
drawing up the Plan the calculations were limited to the test points of the aeronautical
radionavigation station in line of sight from the broadcasting station, it being assumed
that the effective Earth's radius is 4/3 of the actual radius.
2.3 Additional propagation data for the Eastern Mediterranean
In bilateral and multilateral negotiations during the Conference, some administrations
in the Eastern Mediterranean (East of 30° E) calculated the field strength for 1 %
of the time for oversea paths using the following formulae:
E = 106.9 - 20 log d-0.07 d for 10 ≤ d < 100
E= 99.9 -20 logd for 100 ≤ d ≤ 568
E = 78.9 - 0.06 d for d > 568
where
d = path length in km,
E = field strength in dB (μV/m).
FIGURE 2.1
Field strength (dB (µV/m)) for I kW e.r.p.
Propagation over land
50% of the time: 50% of the locations; h2 = 10 m
- . - . - Free space
PROPAGATION CURVES FOR THE BROADCASTING SERVICE
FIGURE 2.2
Field strength (dB (µV/m)) for 1 kWe.r.p.
Propagation over sea
50% of the time; 50% of the locations; h, = 10 m
- . - . - Free space
PROPAGATION CURVES FOR THE BROADCASTING SERVICE
FIGURE 2.3
Field strength (dB (µV/m)) for 1 kW e.r.p.
Propagation over land
1% of the time; 50% of the locations; h2 = 10 m
- . - . - Free space
PROPAGATION CURVES FOR THE BROADCASTING SERVICE
FIGURE 2.4
Field strength (dB (µV/m)) for 1 kWe.r.p.
Propagation over cold sea
1 % of the time; 50% of the locations; h2 = 10 m
- . - . - Free space
PROPAGATION CURVES FOR THE BROADCAST1NG SERVICE
FIGURE 2.5
Field strength (dB (µV/m)) for 1 kW e.r.p.
Propagation over warm sea
(excluding areas subject to extreme super-refractivity)
1 % of the time; 50% of ths locations; h2 = 10 m
- . - . - Free space
PROPAGATION CURVES FOR THE BROADCASTING SERVICE
CHAPTER 3
Technical standards and transmission characteristics for the sound broadcasting service
3.1 Transmission systems
In planning, the following transmission systems were used, as specified by the administrations
when notifying their requirements:
System 1: Monophonic (maximum frequency deviation + 75 kHz)
System 2: Monophonic (maximum frequency deviation ± 50 kHz)
System 3: Stereophonic, polar modulation system (maximum frequency deviation + 50
kHz)
System 4: Stereophonic, pilot-tone system (maximum frequency deviation + 75 kHz)
System 5: Stereophonic, pilot-tone system (maximum frequency deviation + 50 kHz)
Column 9 of the Plan indicates the system used in accordance with the above classification.
The addition of sub-carriers for the transmission of supplementary informationwas considered as being included in each of the five systems above, provided that
the maximum carrier frequency deviation was not exceeded and the protection required
was not increased.
As an alternative, other systems having different characteristics (e.g. other pre-emphasis
characteristics, digital modulation) may be used, provided that such use does neither
cause greater interference nor demand higher protection than the reference system
indicated in the Plan.
3.2 Channel spacing
A uniform channel spacing of 100 kHz was adopted in principle for both monophonic
and stereophonic emissions.
The nominal carrier frequencies are, in principle, integral multiples of 100 kHz.
3.3 Modulation standards
3.3.1 Monophonic transmissions
The radio-frequency signal consists of a carrier frequency modulated by the sound
signal after preemphasis with a maximum frequency deviation of ±75 kHz or +50 kHz.
The pre-emphasis characteristic of the sound signal is identical to the admittance-frequency
curve of a parallel resistance-capacitance circuit having a time constant of 50 μs.
3.3.2 Stereophonic transmissions
The radio-frequency signal consists of a carrier frequency modulated by baseband signal
according to the specifications of the polar modulation or the pilot-tone system.
The maximum frequency deviation is + 50 kHz for the polar modulation system and +75
kHz or +50 kHz for the pilot-tone system.
The pre-emphasis characteristics of the sound signals M and Sare identical to the admittance-frequency curve of a parallel resistancecapacitance
circuit having a time constant of 50 μs.
3.4 Protection ratios
3.4.1 Monophonic transmissions
The radio-frequency protection ratios required to give satisfactory monophonic reception
for 99 % of the time are given by the curve M2 in Figure 2.6 for systems using a maximum
frequency deviation of +75 kHz. For steady interference a higher degree of protection
is required; this is shown by the curve M1 in Figure 2.6. The protection ratios at
specific frequency spacing values are also given in Table 2.1.
The corresponding values for systems using a maximum frequency deviation of + 50 kHz
are given in Figure 2.7 and Table 2.2.
3.4.2 Stereophonic transmissions
The radio-frequency protection ratios required to give satisfactory stereophonic reception
for 99% of the time are given by curve S2 in Figure 2.6 for transmissions using the
pilot-tone system and a maximum frequency deviation of + 75 kHz. For steady interference,
a higher degree of protection is required; this is shown by the curve S1 in Figure
2.6. The protection ratios at specific frequency spacing values are also given in
Table 2.1.
Table 2.2 and Figure 2.7 give the radio-frequency protection ratios required for satisfactory
reception in the case of tropospheric interference (99% of time), or in the case of
steady interference for stereophonic transmissions using the pilot-tone system or
the polar modulation system with a maximum frequency deviation of + 50 kHz.
Table 2.3 gives the radio-frequency protection ratios required for satisfactory stereophonic
reception in the case of tropospheric interference (99% of time), or in the case of
steady interference where the wanted and interfering transmitters use different maximum
frequency deviations.
The protection ratios for stereophonic broadcasting assume the use of a lowpass filter
following the frequency modulation demodulator in the receiver designed to reduce
interference and noise at frequencies greater than 53 kHz in the pilot-tone system
and greater than 46.25 kHz in the polar modulation system. Without such a filter or
an equivalent arrangement in the receiver, the protection-ratio curves for stereophonic
broadcasting cannot be met, and significant interference from transmission in adjacent
or nearby channels is possible.
Note - The protection ratios for steady interference provide approximately a 50 dB signal-to-noise
ratio. (Weighted quasi-peak measurement in conformity with CCIR Recommendation 468-3,
with a reference signal at maximum frequency deviation.)
FIGURE 2.6
Radio-frequency protection ratio required by broadcasting services in Band 8 (VHF)
at frequencies between 87.5 MHz and 108 MHz using a maximum frequency deviation of
+ 75 kHz
Curve M1: monophonic broadcasting; steady interference
Curve M2: monophonic broadcasting; tropospheric interference
(protection for 99% of the time)
Curve S1: stereophonic broadcasting; steady interference
Curve S2: stereophonic broadcasting; tropospheric interference
(protection for 99% of the time)
TABLE 2.1
|
Frequency spacing (kHz)
|
Radio-frequency protection ratio (dB) for a maximum frequency deviation of + 75 kHz
|
|
Monophonic
|
Stereophonic
|
|
Steady interference
|
Tropospheric interference
|
Steady interference
|
Tropospheric interference
|
|
0
|
36
|
28
|
45
|
37
|
|
25
|
31
|
27
|
51
|
43
|
|
50
|
24
|
22
|
51
|
43
|
|
75
|
16
|
16
|
45
|
37
|
|
100
|
12
|
12
|
33
|
25
|
|
150
|
8
|
8
|
18
|
14
|
|
200
|
6
|
6
|
7
|
7
|
|
250
|
2
|
2
|
2
|
2
|
|
300
|
-7
|
-7
|
-7
|
-7
|
|
350
|
-15
|
-15
|
-15
|
-15
|
|
400
|
-20
|
-20
|
-20
|
-20
|
FIGURE 2.7
Radio-frequency protection ratio required by broadcasting services in Band 8 (VHF)
at frequencies between 87-5 MHz and 108 MHz using a maximum frequency deviation of
+50 kHz
Curve Ml: monophonic broadcasting; steady interference
Curve M2: monophonic broadcasting; tropospheric interference
(protection for 99% of the time)
Curve S1: stereophonic broadcasting; steady interference
Curve S2: stereophonic broadcasting; tropospheric interference
(protection for 99% of the time)
TABLE 2.2
|
Frequency spacing (kHz)
|
Radio-frequency protection ratio (dB) for a maximum frequency deviation of ± 50 kHz
|
|
Monophonic
|
Stereophonic
|
|
Steady interference
|
Tropospheric interference
|
Steady interference
|
Tropospheric interference
|
|
0
|
39
|
32
|
49
|
41
|
|
25
|
32
|
28
|
53
|
45
|
|
50
|
24
|
22
|
51
|
43
|
|
75
|
15
|
15
|
45
|
37
|
|
100
|
12
|
12
|
33
|
25
|
|
125
|
7.5
|
7.5
|
25
|
18
|
|
150
|
6
|
6
|
18
|
14
|
|
175
|
-2.5
|
2
|
12
|
11
|
|
200
|
-3.5
|
-2.5
|
7
|
7
|
|
225
|
-6
|
-3.5
|
5
|
5
|
|
250
|
2
|
-6
|
2
|
2
|
|
275
|
-7.5
|
-7.5
|
0
|
0
|
|
300
|
-10
|
-10
|
-7
|
-7
|
|
325
|
-12
|
-12
|
-10
|
-10
|
|
350
|
-15
|
-15
|
-15
|
-15
|
|
375
|
-17.5
|
-17.5
|
-17.5
|
-17.5
|
|
400
|
-20
|
-20
|
-20
|
-20
|
TABLE 2.3
|
Frequency spacing (kHz)
|
Maximum frequency deviation:
wanted transmitter ± 50 kHz
interfering transmitter ± 75 kHz
|
Maximum freq uency deviation:
wanted transmitter ± 75 kHz
interfering transmitter ± 50 kHz
|
|
Radio-frequencyprotection ratio (dB) stereophonic
|
Radio-frequencyprotection ratio (dB) stereophonic
|
|
Steady interference
|
Tropospheric interference
|
Steady interference
|
Tropospheric interference
|
|
0
|
49
|
41
|
45
|
37
|
|
25
|
53
|
45
|
51
|
43
|
|
50
|
51
|
43
|
51
|
43
|
|
75
|
45
|
37
|
45
|
37
|
|
100
|
33
|
25
|
33
|
25
|
|
125
|
25
|
18
|
24.5
|
18
|
|
150
|
18
|
14
|
18
|
14
|
|
175
|
12
|
11
|
11
|
10
|
|
200
|
7
|
7
|
7
|
7
|
|
225
|
5
|
5
|
4.5
|
4.5
|
|
250
|
2
|
2
|
2
|
2
|
|
275
|
0
|
0
|
-2
|
-2
|
|
300
|
-7
|
-7
|
-7
|
-7
|
|
325
|
-10
|
-10
|
-11.5
|
-11.5
|
|
150
|
-15
|
-15
|
-15
|
-15
|
|
375
|
-17.5
|
-17.5
|
-17.5
|
-17.5
|
|
400
|
-20
|
-20
|
-20
|
-20
|
3.5 Calculation of nuisance field
To apply the protection-ratio curves of Figures 2.6 and 2.7, it is necessary to determine
whether, in the particular circumstances, the interference is to be regarded as steady
or tropospheric. A suitable criterion for this is provided by the concept of "nuisance field", which
is the field strength of the interfering transmitter (at its pertinent e.r.p.) modified
by the relevant protection ratio.
Thus, the nuisance field for steady interference is given by the formula:
Es = P + E (50,50) + As
and the nuisance field for tropospheric interference is given by the formula:
Et = P + E(50, T) + At
where
|
P:
|
e.r.p. (dB (1 kW)) of the interfering transmitter;
|
|
A:
|
radio-frequency protection ratio (dB);
|
|
E(50, T):
|
field strength (dB (μV/m)) of the interfering transmitter, normalized to 1 kW, and
exceeded during T% of the time,
|
and where indices s and t indicate steady or tropospheric interference respectively.
The protection-ratio curve for steady interference is applicable when the resulting
nuisance field is stronger than that resulting from tropospheric interference,
i.e.Es ≥ Et.
This means that As should be used in all cases when:
E(50,50) + As ≥ E(50, T) + At.
3.6 Minimum field strength
The planning was based on the following median values of the minimum usable field
strength (measured 10 m above ground level):
- stereophonic service: 54 dB (μV/m) in rural areas;
- monophonic service: 48 dB (μV/m) in rural areas.
These values apply for systems with a maximum frequency deviation of ±50 kHz or ±75
kHz.
3.7 Maximum radiated power
No maximum power values have been specified.
3.8 Characteristics of transmitting and receiving antennas - polarization
3.8.1 Transmitting antennas
The maximum effective radiated power and, in the case of directional antennas, the
azimuth(s) relative to True North together with the azimuths of the - 3 dB points
anti-clockwise and clockwise from the azimuth of the maximum, have been indicated
in accordance with the Radio Regulations (Appendix 1, section D, column 9).
The attenuation (dB) with respect to the maximum value of the effective radiated power
has been specified at 10° intervals in a clockwise direction starting at True North.
Where administrations have been unable to give information in such detail, they have,
where possible, provided the values at 30° intervals in a clockwise direction starting
at True North.
For mixed polarized transmissions, the effective radiated powers and radiation patterns
have been specified separately for the horizontally and vertically polarized components.
3.8.2 Receiving antennas
For stereophonic transmissions, the directivity curve in Figure 2.8 was taken into
account by administrations for assessing coverage areas. For monophonic transmissions,
an omnidirectional receiving antenna was assumed.
In the computer analysis of the Plan during the Conference, no account was taken of
receiving antenna directivity, since the usable field strength was calculated at the
transmitter site.
The antenna was assumed to be at a height of 10 m above the ground.
FIGURE 2.8
Discrimination obtained by the use of a directional receiving antenna for sound broadcasting
stations in the band 87.5 to 108 MHz
Note 1 - It is considered that the protection shown will be available at the majority of
antenna locations in built-up areas. At clear sites in open country, slightly higher
values will be obtained.
Note 2 - The curve in Figure 2.8 is valid for signals of vertical or horizontal polarization,
when both the wanted and the unwanted signals have the same polarization.
3.8.3 Polarization
Administrations were free to choose the polarization to be used in their countries.
Polarization discrimination was not taken into account in the planning procedure,
except in specific cases with the agreement of affected administrations. In such cases,
a value of 10 dB was used for orthogonal polarization discrimination.
3.9 Receiver sensitivity and selectivity
Receiver sensitivity and selectivity were taken into account when specifying the values
of the minimum usable field strength and the radio-frequency protection ratios.
CHAPTER 4
Determination of the usable field strength by the simplified multiplication method
4.1 Principle of calculation
The usable field strength is determined for a specified coverage probability (with
respect to time and location) and depends on the values of the nuisance fields:
E si = Pi + Eni (50, T) + Ai + Bi
where:
|
Esi:
|
the nuisance field of the ithtransmitter corrected by the discrimination factor of the receiving antenna,
|
|
Pi:
|
the e.r.p. in dB (kW) of the ith unwanted transmitter,
|
|
Eni(50, T):
|
the field strength, in dB (μV/m), normalized to an e.r.p. of 1 kW, of the ith unwanted transmitter. The field strength is exceeded at 50 % of the locations during
at least T% (e.g. 1 %) of the time,
|
|
Ai:
|
the radio-frequency protection ratio, in dB, associated with the ith unwanted transmitter,
|
|
Bi:
|
the receiving antenna discrimination, in dB.
|
Appropriate account of the effect of multiple interference can be taken by the use
of statistical computation methods among which the simplified multiplication method
is the least complex. With this method the usable field strength Eu can be calculated by iteration from:
where
|
pc:
|
the coverage probability (e.g. 50% of locations, (100 -T)% of time) in the presence of n nuisance fields;
|
|
L(x):
|
the coverage probability in the presence of a single nuisance field, which equals
the probability integral for a normal distribution (see section 4.2 below).
|
|
σn = 8.3 dB:
|
standard deviation according to location of the wanted and interfering field strengths,
in dB (μV/m).
|
4.2 Calculation by computer
The calculation of the usable field strength with the simplified multiplication method
is based on the probability integral for a normal distribution:
This integration can, however, be avoided in the practical calculation by replacing
it with a polynomial approximation as followd:
L (x) = 1 - ½(1 + a1x + a2x2 + a3x3 + a4x4)-4 + ε(x)
with
a 1 = 0.196854
a 2 = 0.115194
a 3 = 0.000344
a 4 = 0.019527
ε (x) represents the error between the approximation and the exact value, obtained
by the probability integral. Since |ε(x)| is less than 2.5.10 -4, this error can be neglected.
The above approximation was used to calculate the multiple interference by the simplified
multiplication method.
4.3 Manual calculation
The basic material for the manual calculation of the usable field strength in applying
the simplified multiplication method is given below.
The manual calculation needs only additions, subtractions, multiplications, divisions
and the reading of a value from Table 2.4.
An example with five interfering transmitters is given in Table 2.5.
Experience has shown that it is expedient to begin with a value for Eu 6 dB larger than the largest of the Esi values. If the difference between 0.52 and the result (product of the 5 values of L(xi)) equals Δ, the value of Eu should be modified by Δ /0.05 to obtain a better approximation. The whole process
can be repeated to obtain better accuracy.
Table 2.5 shows that even after the second step, the difference between the value
obtained and the precise value is of the order of 0.2 dB.
TABLE 2.4
|
X
|
φ(x)
|
x
|
φ(x)
|
x
|
φ(x)
|
x
|
φ(x)
|
|
0.00
|
0.0000
|
0.60
|
0.4515
|
1.20
|
0.7699
|
1.80
|
0.9281
|
|
01
|
0.0080
|
61
|
0.4581
|
21
|
0.7737
|
81
|
0.9297
|
|
02
|
0.0160
|
62
|
0.4647
|
22
|
0.7775
|
82
|
0.9312
|
|
03
|
0.0239
|
63
|
0.4713
|
23
|
0.7813
|
83
|
0.9328
|
|
04
|
0.0319
|
64
|
0.4778
|
24
|
0.7850
|
84
|
0.9342
|
|
0.05
|
0.0399
|
0.65
|
0.4843
|
1.25
|
0.7887
|
1.85
|
0.9357
|
|
06
|
0.0478
|
66
|
0.4907
|
26
|
0.7923
|
86
|
0.9371
|
|
07
|
0.0558
|
67
|
0.4971
|
27
|
0.7959
|
87
|
0.9385
|
|
08
|
0.0638
|
68
|
0.5035
|
28
|
0.7995
|
88
|
0.9399
|
|
09
|
0.0717
|
69
|
0.5098
|
29
|
0.8029
|
89
|
0.9412
|
|
0.10
|
0.0797
|
0.70
|
0.5161
|
1.30
|
0.8064
|
1.90
|
0.9426
|
|
11
|
0.0876
|
71
|
0.5223
|
31
|
0.8098
|
91
|
0.9439
|
|
12
|
0.0955
|
72
|
0.5285
|
32
|
0.8132
|
92
|
0.9451
|
|
13
|
0.1034
|
73
|
0.5346
|
33
|
0.8165
|
93
|
0.9464
|
|
14
|
0.1113
|
74
|
0.5407
|
34
|
0.8198
|
94
|
0.9476
|
|
0.15
|
0.1192
|
0.75
|
0.5467
|
1.35
|
0.8230
|
1.95
|
0.9488
|
|
16
|
0.1271
|
76
|
0.5527
|
36
|
0.8262
|
96
|
0.9500
|
|
17
|
0.1350
|
77
|
0.5587
|
37
|
0.8293
|
97
|
0.9512
|
|
18
|
0.1428
|
78
|
0.5646
|
38
|
0.8324
|
98
|
0.9523
|
|
19
|
0.1507
|
79
|
0.5705
|
39
|
0.8355
|
99
|
0.9534
|
|
0.20
|
0.1585
|
0.80
|
0.5763
|
1.40
|
0.8385
|
2.00
|
0.9545
|
|
21
|
0.1663
|
81
|
0.5821
|
41
|
0.8415
|
05
|
0.9596
|
|
22
|
0.1741
|
82
|
0.5878
|
42
|
0.8444
|
10
|
0.9643
|
|
23
|
0.1819
|
83
|
0.5935
|
43
|
0.8473
|
15
|
0.9684
|
|
24
|
0.1897
|
84
|
0.5991
|
44
|
0.8501
|
20
|
0.9722
|
|
0.25
|
0.1974
|
0.85
|
0.6047
|
1.45
|
0.8529
|
2.25
|
0.9756
|
|
26
|
0.2041
|
86
|
0.6102
|
46
|
0.8557
|
30
|
0.9786
|
|
27
|
0.2128
|
87
|
0.6157
|
47
|
0.8584
|
35
|
0.9812
|
|
28
|
0.2205
|
88
|
0.6211
|
48
|
0.8611
|
40
|
0.9836
|
|
29
|
0.2282
|
89
|
0.6265
|
49
|
0.8638
|
45
|
0.9857
|
|
0.30
|
0.2358
|
0.90
|
0.6319
|
1.50
|
0.8664
|
2.50
|
0.9876
|
|
31
|
0.2434
|
91
|
0.6372
|
51
|
0.8690
|
55
|
0.9892
|
|
32
|
0.2510
|
92
|
0.6424
|
52
|
0.8715
|
60
|
0.9907
|
|
33
|
0.2586
|
93
|
0.6476
|
53
|
0.8740
|
65
|
0.9920
|
|
34
|
0.2661
|
94
|
0.6528
|
54
|
0.8764
|
70
|
0.9931
|
|
0.35
|
0.2737
|
0.95
|
0.6579
|
1.55
|
0.8789
|
2.75
|
0.9940
|
|
36
|
0.2812
|
96
|
0.6629
|
56
|
0.8812
|
80
|
0.9949
|
|
37
|
0.2886
|
97
|
0.6680
|
57
|
0.8836
|
85
|
0.9956
|
|
38
|
0.2961
|
98
|
0.6729
|
58
|
0.8859
|
90
|
0.9963
|
|
39
|
0.3035
|
99
|
0.6778
|
59
|
0.8882
|
95
|
0.9968
|
|
0.40
|
0.3108
|
1.00
|
0.6827
|
1.60
|
0.8904
|
3.00
|
0.99730
|
|
41
|
0.3182
|
01
|
0.6875
|
61
|
0.8926
|
10
|
0.99806
|
|
42
|
0.3255
|
02
|
0.6923
|
62
|
0.8948
|
20
|
0.99863
|
|
43
|
0.3328
|
03
|
0.6970
|
63
|
0.8969
|
30
|
0.99903
|
|
44
|
0.3401
|
04
|
0.7017
|
64
|
0.8990
|
40
|
0.99933
|
|
0.45
|
0.3473
|
1.05
|
0.7063
|
1.65
|
0.9011
|
3.50
|
0.99953
|
|
46
|
0.3545
|
06
|
0.7109
|
66
|
0.9031
|
60
|
0.99968
|
|
47
|
0.3616
|
07
|
0.7154
|
67
|
0.9051
|
70
|
0.99978
|
|
48
|
0.3688
|
08
|
0.7199
|
.68
|
0.9070
|
80
|
0.99986
|
|
49
|
0.3759
|
09
|
0.7243
|
69
|
0.9090
|
90
|
0.99990
|
|
0.50
|
0.3829
|
1.10
|
0.7287
|
1.70
|
0.9109
|
4.00
|
0.99994
|
|
51
|
0.3899
|
11
|
0.7330
|
71
|
0.9127
|
|
|
|
52
|
0.3969
|
12
|
0.7373
|
72
|
0.9146
|
|
|
|
53
|
0.4039
|
13
|
0.7415
|
73
|
0.9164
|
|
|
|
54
|
0.4108
|
14
|
0.74S7
|
74
|
0.9181
|
|
|
|
0.55
|
0.4177
|
1.15
|
0.7499
|
1.75
|
0.9199
|
|
|
|
56
|
0.4245
|
16
|
0.7540
|
76
|
0.9216
|
|
|
|
57
|
0.4313
|
17
|
0.7580
|
77
|
0.9233
|
|
|
|
58
|
0.4381
|
18
|
0.7620
|
78
|
0.9249
|
4.417
|
1 - 10-5
|
|
59
|
0.4448
|
19
|
0.7660
|
79
|
0.9265
|
4.892
|
1 - 10--6
|
|
0.60
|
0.4515
|
1.20
|
0.7699
|
1.80
|
0.9281
|
5.327
|
1 - 10--7
|
TABLE 2.5
CHAPTER 5
Frequency compatibility between sound and television broadcasting
5.1 Introduction
Several countries are operating television transmitters using the D/SECAM system in
the band 87.5-100 MHz. All sound broadcasting requirements for stations in the area
of coordination with countries using this band for television in accordance with the
Regional Agreement (Stockholm, 1961), have been assessed for compatibility with television
stations.
5.2 Protection of sound-broadcasting stations within the coordination area
Calculations have been carried out to verify that there is no deterioration in the
service areas of existing sound broadcasting stations which are operating in accordance
with the Regional Agreement (Stockholm, 1961) (notified to the IFRB before 1 December
1983) and which are situated in the area of coordination with countries using this
band for television in accordance with the Regional Agreement (Stockholm, 1961). For
purposes of comparison, the reference situation (as described in section 5.4 below)
has been used as a basis.
A sound broadcasting station was considered to be situated in the coordination area
when its distance from the nearest point of the border of the country using this band
for television in accordance with the Regional Agreement (Stockholm, 1961) is less
than the distance in Table B of Annex 1 to the Stockholm Agreement.
5.3 Comparison
For the purpose of assessing compatibility with television stations (see section 5.1
above) or protection to service areas of existing sound broadcasting transmitters
(see section 5.2 above), the existing situation has been used as a reference situation
and has been compared with the new Plan in the course of its development. To permit
these comparisons, it has been necessary to calculate (as in section 5.6 below) the
usable field strength (Eu) for all television transmitters and all existing sound broadcasting stations (as
in sections 5.1 and 5.2 above) at a number of test locations (not more than 12) within
the existing service area, as specified by the administrations concerned.
5.4 Reference situation
All existing or planned assignments to television or sound broadcasting stations in
the band 87.5-100 MHz appearing in the Regional Plan (Stockholm, 1961) and those for
which the procedure of the Regional Agreement (Stockholm, 1961) has been successfully
applied before the date of the opening of the Second Session of the Conference, have
been taken into account. The sound broadcasting stations in Region 3 and in the part
of Turkey not covered by the Regional Agreement (Stockholm, 1961) which are operating
in accordance with the Radio Regulations and notified to the IFRB before 1 December
1983 have been included in the reference situation. The calculation for the reference
situation has only been made once.
5.5 Situation resulting from planning
All existing or planned assignments to television stations (as in section 5.4 above)
and all sound broadcasting transmitters in the draft Plan have been taken into account.
5.6 Usable field strength for a transmitter at the specified test location
5.6.1 The nuisance field from each interfering transmitter was calculated according
to section 3.5 of Chapter 3 using, in principle, propagation curves for 1 % of the
time and the appropriate protection ratio taken:
5.6.1.1 for the wanted television transmitter,
- from Table 2.6 for interference from a television transmitter, or
- from Figure 2.9 for interference from a sound broadcasting transmitter.
Note - Since the protection ratio curve for the D/SECAM television broadcasting system
against FM sound broadcasting interference is not defined for deviations of 6-7 MHz
from the vision carrier frequency (see Figure 2.9), the protection of the sound carrier,
considered as modulated according to system 2, was calculated separately.
5.6.1.2 for a wanted sound broadcasting transmitter,
- from Table 2.7 or Figure 2.10 for interference from a television transmitter, using
protection ratio values for tropospheric interference, or
- from section 3.4 of Chapter 3 for interference from a FM sound broadcasting transmitter.
5.6.2 Receiving antenna discrimination is taken,
- from Figure 2.11 for a wanted television transmitter,
- from Figure 2.8 in Chapter 3 for a wanted sound broadcasting transmitter.
5.6.3 For orthogonal polarization, a discrimination value of 10 dB was applied for
a wanted television transmitter. No polarization discrimination was applied for a
wanted sound broadcasting transmitter.
5.6.4 The interference contribution of each interfering transmitter is the value of
the nuisance field derived from section 5.6.1, plus any discrimination value derived
from sections 5.6.2 or 5.6.3.
5.6.5 The usable field strength Eu was calculated from the individual interference contributions using the simplified
multiplication method, taking into account the 20 largest (either TV or sound broadcasting)
contributions and specified to one decimal place.
5.7 Results of examination
An incompatibility with a television station or a deterioration of the service area
of a sound broadcasting station exists only if any value of Eu obtained (as in section 5.6), in accordance with section 5.5, exceeds the corresponding
value of Eu in the reference situation defined in section 5.4 by more than 0.5 dB.
TABLE 2.6
Protection ratios, in dB, for two colour television transmissions with the same number
of lines
|
Offset (multiples of 1/12 line-frequency)
|
0
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
11
|
12
|
|
Co-channel Transmitter stability ± 500 Hz (non-precision offset)
|
45
|
44
|
40
|
14
|
30
|
28
|
27
|
28
|
310
|
14
|
40
|
44
|
45
|
|
Lower adjacent channel
|
-6
|
|
Upper adjacent channel
|
+ 4
|
FIGURE 2.9
D/SECAM television system protection ratio in the case of frequency-modulated sound
broadcasting tropospheric interference
Note - For steady interference 10 dB are added.For further information see CCIR Report
306-4.
TABLE 2.7
Radio-frequency protection ratio required by FM sound broadcasting against interference
from D/SECAM television transmissions 87.5 to 100 MHz
(Steady interference)
|
Wanted signal frequency (MHz) relative to vision carrier
|
RF protection ratio (dB)
|
|
mono
|
stereo
|
|
-2.0
-1.0
-0.5
-0.15
-0.1
-0.05
0.0
0.05
0.1
0.15
0.25
0.5
1.0
2.0
3.0
4.0
4,18
4.25
4.41
4.48
4.7
5.0
6.0
6.25
6.3
64
6.45
6.475
6.525
6.55
6.6
6.7
7.0
|
-30
-2
0
19
24
30
35
30
24
19
10
0
-1
-3
-4
-5
8
10
10
8
-5
-15
-25
-13
5
6
15
25
28
25
15
6
-3 -30
|
-12
18
20
25
5
50
45
50
35
31
25
20
20
18
17
15
25
26
25
15
0
-5
-6
5
26
40
43
35
43
40
26
0
-13
|
Note 1 - For tropospheric interference (protection 99% of the time) these values may be
reduced by 8 dB.
Note 2 - Values for frequencies from 0.5 to 4 MHz are greatly affected by picture content.
The figures given are for a test pattern and are representative of the on-the-air
test picture transmissions.
Note 3 - This table is valid for a vision/sound carrier power ratio of 10 dB.
FIGURE 2.10
Radio-frequency protection ratio required by FM sound broadcasting against interference
from D/SECAM television transmissions in the band 87.5 to 100 MHz (steady interference)
Note 1 - For tropospheric interference (protection 99% of the time) these values may be reduced
by 8 dB.
Note 2 - This figure is valid for a vision/sound carrier power ratio of 10dB.
FIGURE 2.11
Discrimination obtained by the use of a directional receiving antenna for television
stations in the band 87.5 to 100 MHz
CHAPTER 6
Analysis of the Plan
6.1 Introduction
The Plan was analyzed on the basis of information supplied by administrations before
or during the Second Session of the Conference or entered by the IFRB for administrations
failing to supply information.
6.2 Method of analysis
In each analysis, the nuisance of field from each potentially interfering transmitter
was calculated at the site of the wanted transmitter by the method given in section
3.5 of Chapter 3.
The usable field strength, Eu, was then calculated by the simplified multiplication method, taking into account
the 20 largest values of nuisance field, specified to one decimal place. For the analysis
of the Plan during the Conference, the simplified multiplication method was used for
the whole of the planning area; however, for comparison purposes, the power sum methodwas also used.
Sharing the television broadcasting in the European Broadcasting Area operating in
accordance with the Regional Agreement (Stockholm, 1961) in the band 87.5-100 MHz
(see Chapter 5) was taken into account.
The method of analysis using during the Conference with respect to compatibility with
the aeronautical radionavigation service in the band 108-117.975 MHz is described
in Chapter 7.
6.2.1 Analysis during the Conference
The computer analysis of the Plan during the Conference was based on the methods and
criteria given in Chapters 2 to 5 and 7, but it did not take into account any receiving
antenna discrimination.
6.2.2 Analysis during the implementation of the Plan
After the Conference, the analysis of the Plan is to be based on the simplified multiplication
method. The results based on the power sum method will also be provided on request
for information only.
CHAPTER 7
Compatibility between the broadcasting service in the band 87.5-108 MHz and the aeronautical
radionavigation service in the band 108-117.975 MHz
7.1 Introduction
7.1.1 The criteria contained in this chapter were used for the assessment of compatibility
between sound broadcasting stations in the band 87.5-108 MHz, and aeronautical radionavigation
stations in the band 108-117.975 MHz.
7.1.2 The coordination contour method, as specified in section 7.3, was used in the
determination of a potential incompatibility between the sound broadcasting stations
of one country and the aeronautical radionavigation stations of another country. Such
cases have been or will be settled through bilateral and multilateral negotiations
between the administrations concerned.
7.1.3 Where the stations of the broadcasting service and the aeronautical radionavigation
service belong to one and the same country, the administration concerned has conducted
or will conduct an examination in order to find an appropriate solution.
7.2 Interference mechanisms
7.2.1 Type A interference: Due to radiation at frequencies in the aeronautical radionavigation band
These comprise the following:
Type Al: Intermodulation or other spurious products radiated from the broadcasting
station;
Type A2: Out-of-band emissions from broadcasting stations in the aeronautical radionavigation
band immediately above the band edge of 108 MHz.
7.2.2 Type B interference: Due to radiation at frequencies outside the aeronautical radionavigation band
These comprise the following:
Type Bl: Intermodulation generated in the receiver;
Type B2: Desensitization in the RF section of the receiver.
7.3 Coordination contour around the test point of an aeronautical radionavigation station
7.3.1 The coordination contour is defined by the projection on the Earth's surface
of circles around each test point of the radionavigation station to be protected,
with a radius as defined in sections 7.3.2 and 7.3.3. Broadcasting stations outside
the coordination contour were considered as being unlikely to affect the service provided
by the aeronautical radionavigation station concerned and were therefore disregarded.
7.3.2 For types Al, A2 and B2 interference the radius is 125km.
7.3.3 For type B1 interference the radius is 500km.
7.3.4 Only broadcasting stations which are in line-of-sight of the test point concerned
were taken into account (see Chapter 2, section 2.2).
7.4 Test points
The calculations were limited to four test points only. These test points were chosen
by the administration concerned in accordance with the conditions described in sections
7.4.1 and 7.4.2.
As the number of test points is insufficient, the administrations concerned may introduce
additional test points for future coordination between administrations.
7.4.1 Instrument landing system (ILS)
Points A, B, C and D are defined in Figure 2.12. In some cases, the height of test
point A differed from that indicated in Figure 2.12.
7.4.2 VHF omnidirectional range (VOR)
The four cardinal points (N, E, S and W) of the circle forming the boundary of the
service area at a height of 1000 m above the VOR were chosen as test points by certain
administrations. Other administrations preferred four other test points (with different
locations, or heights, or both), which they considered more significant.
7.5 Polarization
No account was taken of polarization differences between the broadcasting and the
aeronautical radionavigation signals except in special cases (e.g. circular polarization
of the broadcasting signal).
The interfering signals were assumed to have the same polarization (vertical or horizontal)
as the navigation system. If, instead, the broadcasting signal has a different polarization,
there is in theory some reduction of received interfering signal levels, but it was
agreed not to make any allowance. In cases, however, where an equal power in the other
plane of polarization is added at the transmitter (e.g. circular polarization), an
allowance was made by adding 1 dB to the effective radiated power of the polarization
component in the same plane as that used by the navigation system.
7.6 Protection criteria for ILS and VOR
Annex 10 to the Convention on International Civil Aviation contains specifications
and characteristics relevant to the protection of both ILS and VOR.
7.6.1 Wanted signal
The minimum field strength to be protected is:
|
-ILS:
|
40µV/m (32dB(μV/m))
|
|
-VOR:
|
90µV/m (39dB(μV/m))
|
FIGURE 2.12
ILS localizer protection volume
----: the limits of the ILS back beam protection volume; in this case, the range and
height are indicated
●(A, B, C, D): test points for the ILS localizer
*(h): altitude indicated by the administration
7.6.2 Principles of calculation
The field strength of every broadcasting station in the band 87.5-108 MHz inside the
coordination contour and within line-of-sight of a test point of an aeronautical radionavigation
station was calculated at this test point as an interfering signal.
For types Al and A2 interference, this field strength was compared with the minimum
field strength to be protected of the wanted signal, as indicated in section 7.6.1.
For type Bl interference the relevant intermodulation formulae were applied.
For type B2 interference the broadcasting signal level was compared with the maximum
permitted level.
Where applicable, the field-strength E was converted to signal power N at the receiver
input according to the following formula:
E(dB(μV/m)) = AT(dBm) + 118 + Ls + L(ƒ)
where:
Ls : system fixed loss of 3.5 dB;
L(f): system frequency-dependent loss at frequency f of 1 dB per MHz from 108-100 MHz and then 0.5 dB per MHz below 100 MHz.
7.6.3 Al interference
7.6.3.1 Protection ratio
A protection ratio of 17 dB was assumed, including a small safety margin in order
to take account of multiple interference entries resulting from different broadcast
transmitters.
7.6.3.2 The field strength of the interfering signal at the test point was calculated
on the basis of the following level of the spurious component (in the case of several
transmitters contributing to one spurious componentsee category a. below - the most
powerful transmitter is taken as the reference in the calculation):
- 40 dB below the transmitter e.r.p. for transmitter e.r.p. below and equal to 2.5
W;
- 250 µW e.r.p. for transmitter e.r.p. above 2.5 W and below 79 kW;
- 85 dB below the transmitter e.r.p. for transmitter e.r.p. equal to and above 79
kW.
An antenna gain of 10 dB was assumed in defining the levels given above.
The levels of the spurious emission given above are valid in the band 108-137 MHz.
7.6.3.3 For the analysis of type Al interference, the following two categories of
spurious emissions exist:
a. spurious emissions resulting from an intermodulation process caused at the transmitter
site, e.g., by multiple transmitters feeding the same antenna;
b. spurious emissions with the exception of those covered by a. above.
Where the actual frequency of the spurious emission is known, Table 2.8 gives the
values of protection ratio to be used for frequency differences up to 200 kHz from
radionavigation transmitters. Type Al interference need not be considered for frequency
differences greater than 200 kHz.
TABLE 2.8
|
Frequency difference (kHz) between spurious emission and wanted signal
|
Protection ratio (dB)
|
|
0
50
100
150
200
|
17
10
-4
-19
-38
|
In the computer analysis during the Conference, the worst case was assumed for category
b., i.e., a spurious component coinciding with the aeronautical frequency under consideration.
7.6.3.4 During the Conference, no analysis was made for category a. due to lack of
data.
7.6.4 Type A2 interference
The protection ratio values are given in Table 2.9.
TABLE 2.9
|
Frequency difference (kHz) between wanted signal and broadcasting signal
|
Protection ratio (dB)
|
|
150
200
250
300
|
-41
-50
-59
-68
|
A frequency difference less than 150 kHz cannot occur. For frequency differences greater
than 300 kHz, this type of interference need not be considered.
7.6.5 Type B1 interference
Third-order intermodulation products of the form:
ƒintermod = 2ƒ1 –ƒ2(two-signal case) or
ƒintermod= ƒ1 + ƒ2 -ƒ3 (three-signal case)
with ƒ1>ƒ2> ƒ3,
generated in the airborne ILS or VOR receiver will cause an unacceptable degradation
of receiver performance, if ƒintermod coincides with or is close to the frequency of the wanted signal and the inequalities
given below are fulfilled subject to the conditions in section 7.6.5.4.
Intermodulation of the second order is irrelevant and intermodulation of a higher
order than three has not been considered.
N 1, N 2 and N 3 in the inequalities below have the following meaning:
N 1... level in dBm of the broadcasting signal of frequency ƒ1 in MHz at the input of the aeronautical radionavigation receiver
N2... level in dBm of the broadcasting signal of frequency ƒ 2 in MHz at the input of
the aeronautical radionavigation receiver
N3... level in dBm of the broadcasting signal of frequency ƒ3 in MHz at the input of the aeronautical radionavigation receiver
max (0.4; 108.1 - ƒ) in the inequalities below has the following meaning: either 0.4
or 108.1 -ƒ whichever is greater.
7.6.5.3 Frequency offset conditions
Before applying the formulas given in sections 7.6.5.1 or 7.6.5.2, a correction is
applied to each broadcasting signal level which is a function of the frequency difference
between the wanted signal and the intermodulation product, this correction is given
in Table 2.10.
N1,2,3 (corrected) = N1,2,3 - correction term.
TABLE 2.10
|
Frequency difference between wanted signal and intermodulation product (kHz)
|
Correction term (dB)
|
|
0
|
0
|
|
±50
|
2
|
|
±100
|
8
|
|
±150
|
16
|
|
±200
|
26
|
For frequency differences beyond + 200 kHz, type B1 interference need not be considered.
7.6.5.4 Trigger and cut-off values
The trigger is the minimum power level at the input to the airborne ILS or VOR receiver
considered necessary for a broadcasting signal to initiate the generation of intermodulation
products which are potentially of sufficient power to exceed the receiver interference
threshold. The trigger value for each contributing broadcasting signal of frequency
ƒ at the ILS or VOR receiver input was derived from the following formula:
The cut-off value is the minimum power level at the input to the airborne ILS or VOR
receiver considered necessary for a broadcasting signal to contribute to the non-linear
process which results in the formation of an intermodulation product potentially of
sufficient power to exceed the receiver interference threshold.
For the compatibility analysis, a cut-off value of 12dB below the trigger value was
chosen.
An intermodulation analysis was therefore carried out only if at least one signal
was equal to or above the trigger value provided that the other signal or signals
were equal to or above the cut-off value.
TABLE 2.11
|
Frequency of broadcasting signal (MHz)
|
Level (dBm)
|
|
107.9
106
102
< 100
|
-20
-5
5
10
|
7.6.6 Type B2 interference
Table 2.11 contains maximum permitted levels of broadcasting signals at the input
to the airborne ILS or VOR receiver.
For intermediate values, the maximum permitted level was determined by linear interpolation.
