In accordance with Article 41 of the Federal Law of July 7, 2003 N 126-FZ "On Communications" (Collected Legislation Russian Federation, 2003, N 28, art. 2895; N 52 (Part I), Art. 5038; 2004, N 35, art. 3607; No. 45, Art. 4377; 2005, N 19, art. 1752; 2006, N 6, Art. 636; No. 10, Art. 1069; N 31 (Part I), Art. 3431, Art. 3452; 2007, N 1, art. 8) and paragraph 4 of the Rules for organizing and carrying out work on mandatory confirmation of the conformity of communication facilities approved by Decree of the Government of the Russian Federation of April 13, 2005 N 214 (Sobraniye Zakonodatelstva Rossiyskoy Federatsii, 2005, N 16, Art. 1463), I order:
1. Approve the attached Rules for the use of subscriber networks of mobile radio communications.
2. Send this order for state registration to the Ministry of Justice of the Russian Federation.
3. To impose control over the execution of this order on the Deputy Minister information technologies and communications of the Russian Federation B.D. Antonyuk.
| Minister | L.D. Reiman |
Registration N 9395
Rules for the use of subscriber radio stations with analog modulation of mobile radio networks
(approved by order of the Ministry of Information Technologies and Communications of the Russian Federation
April 12, 2007 N 46)
I. General provisions
1. The rules for the use of subscriber radio stations with analog modulation of mobile radio networks (hereinafter referred to as the Rules) are developed in accordance with Article 41 of the Federal Law of July 7, 2003 N 126-FZ "On Communications" (Collected Legislation of the Russian Federation, 2003, N 28, 2895; N 52 (part I), item 5038; 2004, N 35, item 3607; N 45, item 4377; 2005, N 19, item 1752; 2006, N 6, item 636; N 10, article 1069; N 31 (part I), article 3431; article 3452; 2007, N 1, article 8) in order to ensure the integrity, stability, operation and security of the unified telecommunication network of the Russian Federation.
2. The Rules establish mandatory requirements for subscriber radio stations with analog modulation (phase or frequency) in mobile radio networks (hereinafter referred to as subscriber radio stations).
3. Subscriber radio stations are subject to declaration of conformity.
4. Subscriber radio stations are used in the radio frequency bands permitted for use by the State Commission on Radio Frequencies.
II. Requirements for subscriber radio stations with analog modulation of mobile radio networks
5. Requirements for the parameters of frequency bands and duplex frequency separations used for connections of subscriber radio stations with base stations, are given in Appendix No. 1 to the Rules.
6. The frequency spacing between adjacent channels of subscriber radio stations is 12.5 and (or) 25 kHz.
7. Subscriber radio stations, depending on the transmitted information, are divided into the following types:
1) subscriber radio stations designed to transmit voice information using angle modulation with a constant envelope;
emission classes - F3E*(1), G3E*(2);
2) subscriber radio stations intended for data transmission using direct carrier modulation or indirect modulation (subcarrier modulation in the audio spectrum). Modulation types - GMSK*(3), MSK*(4), FFSK*(5), multilevel frequency modulation(FM), four- and eight-level phase modulation (FM); emission classes - F1D*(6), G1D*(7);
3) subscriber radio stations designed for the transmission of voice information or data transmission, with mode switching;
4) subscriber radio stations designed to transmit voice information and data transmission simultaneously, have a data transmission path in the subtone frequency region and voice information transmission in the tonal region.
8. Subscriber radio stations perform all procedures for making and receiving a call, establishing, maintaining and releasing a connection with subscriber radio stations of mobile radio networks, mobile radio networks telephone communication And terminal equipment fixed telephone networks and data transmission networks.
9. For transmitters of subscriber radio stations intended for the transmission of voice information, the following mandatory requirements for parameters are established:
1) frequency deviations of transmitters from the nominal value in accordance with Appendix No. 2 to the Rules;
4) frequency deviation of transmitters in accordance with Appendix No. 5 to the Rules;
5) the transmitter radiation level in the adjacent channel for a frequency spacing between adjacent channels of 12.5 kHz does not exceed a value equal to minus 60 dBc or 0.2 μW (minus 37 dBm);
6) the level of transmitter radiation in the adjacent channel for a frequency spacing between adjacent channels of 25 kHz does not exceed a value equal to minus 70 dBc or 0.2 μW (minus 37 dBm);
7) levels of spurious emissions from transmitters in accordance with Appendix No. 6 to the Rules;
8) frequency deviations of transmitters in the transient mode in accordance with Appendix No. 7 to the Rules.
10. For transmitters of subscriber radio stations intended for data transmission, the following mandatory requirements for parameters are established:
1) frequency deviations of transmitters in accordance with Appendix No. 9 to the Rules;
2) carrier power of transmitters of subscriber radio stations with an external antenna connector (on an antenna equivalent) in accordance with Appendix No. 3 to the Rules;
3) the maximum and average effective radiated power (ERP) of subscriber radio station transmitters with a built-in antenna in accordance with Appendix No. 4 to the Rules;
4) the duration of transients when the transmitter is turned on does not exceed the limit value t_a1, equal to 25 ms.
Graphs of transient processes of changing the power and frequency of the carrier when the transmitters are turned on are given in Appendix N 10 to the Rules.
5) the duration of transients when the transmitter is turned off does not exceed the limit value t_r1, equal to 20 ms.
Graphs of transient processes of changing the power and frequency of the carrier when the transmitters are turned off are given in Appendix No. 11 to the Rules.
6) the level of transmitter radiation in the adjacent channel for a frequency spacing between adjacent channels of 12.5 kHz does not exceed a value equal to minus 60 dBc or 0.2 μW (minus 37 dBm);
7) the radiation level in the adjacent channel during transients in the transmitter for a frequency spacing between adjacent channels of 12.5 kHz does not exceed a value equal to minus 50 dBc or 2 μW (minus 27 dBm).
The emission level in the adjacent channel during transients in the transmitter for a frequency spacing between adjacent channels of 25 kHz does not exceed a value equal to minus 60 dBc or 2 μW (minus 27 dBm).
8) levels of transmitter spurious emissions in accordance with Appendix No. 6 to the Rules.
11. For transmitters of subscriber radio stations intended for the transmission of voice information and data transmission, mandatory requirements for parameters are established in accordance with paragraph 9 and subparagraphs 2) - 6) of paragraph 10 of the Rules.
12. For transmitters of subscriber radio stations designed to transmit voice information and transmit data simultaneously, mandatory requirements for parameters are established in accordance with paragraph 9 of the Rules.
13. For receivers of subscriber radio stations, mandatory requirements are established for the parameters:
a) the level of radiation of receivers on the external antenna connector in accordance with Appendix No. 8 to the Rules;
b) the level of radiation of the housing and structural elements of receivers of subscriber radio stations in accordance with Appendix No. 8 to the Rules.
14. The following mandatory requirements for parameters are established for subscriber stations:
1) resistance of subscriber radio stations to climatic influences in accordance with Appendix No. 12 to the Rules;
2) the resistance of subscriber radio stations to mechanical stress in accordance with Appendix No. 13 to the Rules.
15. Requirements for the power supply of subscriber radio stations. The subscriber radio stations are powered, depending on their purpose, from the following power sources:
a) networks alternating current rated voltage 220 V and frequency 50 Hz in the case of using power supplies for portable subscriber radio stations. Subscriber radio stations provide operability when the supply voltage changes in the range from minus 15% to plus 10% relative to the rated voltage of 220 V;
b) external source direct current(on-board network of a mobile object). Subscriber radio stations provide operability when the supply voltage changes in the range from minus 10% to plus 30% relative to the rated voltage of the on-board network of the mobile object;
c) own direct current source ( battery). The type, nominal supply voltage of its own direct current source and the limits of voltage change at which the subscriber radio station remains operational are set by the manufacturer.
_____________________________
*(1) F3E emission class - frequency modulation (F) of one analog telephone channel (3E).
*(2) Class of emission G3E - phase modulation (G) of one analog telephone channel (3E).
*(3) In international practice, the abbreviation GMSK (Gaussian Minimum Shift Keying) is used.
*(4) In international practice, the abbreviation MSK (Minimum Shift Keying - keying with a minimum frequency shift) is used.
*(5) In international practice, the abbreviation FFSK (Fast Frequency Shift Keying) is used.
*(6) Class of emission F1D - frequency modulation (F) of one digital channel data transmission (1D).
*(7) Class of emission G1D - phase modulation (G) of one digital data transmission channel (1D).
Appendix No. 1
radio stations with analog modulation
mobile radio networks
Requirements for the parameters of frequency bands and duplex frequency separations for connections of subscriber radio stations with base stations
For connections of subscriber radio stations with base stations, the frequency ranges and duplex frequency spacings given in the table are used.
_____________________________
*(1) For duplex subscriber radios.
*(2) In international practice, the abbreviation VHF (Very High Frequency) is used.
*(3) In international practice, the abbreviation UHF (Ultrahigh Frequency) is used.
Appendix No. 2
to the Rules for the use of subscriber
radio stations with analog modulation
mobile radio networks
Requirements for the parameters of the frequency deviation of transmitters from the nominal value
1. The frequency deviation of transmitters from the nominal value does not exceed the values given in tables NN 1 and 2.
Table N 1. Frequency deviation of transmitters from the nominal value under normal conditions (hereinafter - NU *)
Table N 2. Frequency deviation of transmitters from the nominal value under extreme conditions (hereinafter referred to as EU**)
_____________________________
* NU are defined in Appendix No. 12 to the Rules.
** ES are defined in Appendix No. 12 to the Rules.
Appendix No. 3
to the Rules for the use of subscriber
radio stations with analog modulation
mobile radio networks
Requirements for carrier power parameters of transmitters (at dummy antenna)
1. The maximum values of the carrier power of the transmitters are given in the table.
2. The deviation of the carrier power of transmitters from the nominal value at NU is within + -1.5 dB.
3. The deviation of the carrier power of the transmitters from the nominal value at the ES is in the range from minus 3.0 to plus 2.0 dB.
_____________________________
* For portable subscriber radio stations.
** For portable subscriber radio stations.
Appendix No. 4
to the Rules for the use of subscriber
radio stations with analog modulation
mobile radio networks
Requirements for parameters of maximum and average effective radiated power of transmitters
1. The nominal values of the maximum and average EIM of transmitters are declared by the manufacturer of subscriber radio stations.
2. The deviation of the maximum EIM of transmitters from the nominal value at NU is within +-d_f.
3. The deviation of the average EIM of transmitters from the nominal value at NU is within +-d_f.
4. Deviation of the maximum (average) EIM of transmitters d_f (dB) from the nominal value at NU is calculated by the formula*:
2 2 d = square root of (d + d), (1) f m e
<= +- 6 дБ); d_e - допустимое отклонение параметра (d_e = +- 1,5 дБ).
5. The deviation of the maximum EIM of transmitters from the nominal value at the EI is in the range from minus d_f2 to plus d_f1.
6. The deviation of the average EIM of transmitters from the nominal value at the ES is in the range from minus d_f2 to plus d_f1.
7. Deviation of the maximum (average) EIM of transmitters d_f1 (dB) from the nominal value at ES is calculated by the formula*:
2 2 d = square root of (d + d), (2) f1 m e1
where d_m is the measurement error (d_m<= +-6 дБ); d_e1 - допустимое отклонение параметра (d_e1 = + 2 дБ).
8. Deviation of the maximum (average) EIM of transmitters d_f2 (dB) from the nominal value at EI is calculated by the formula *:
2 2 d = square root of (d + d), (3) f2 m e2
where d_m is the measurement error (d_m<= +-6 дБ); d_e2 - допустимое отклонение параметра (d_e2 = - 3 дБ).
_____________________________
* When calculating according to formulas 1, 2, 3, all values are expressed in linear units.
Appendix No. 5
to the Rules for the use of subscriber
radio stations with analog modulation
mobile radio networks
Requirements for transmitter frequency deviation parameters
1. The maximum allowable transmitter frequency deviation (D_max) at modulating signal frequencies in the band from the lower frequency f_1 to the upper frequency f_2 at NL does not exceed the values given in the table.
The lower frequency of the modulating signal f_1 is declared by the manufacturer of subscriber radio stations.
2. Frequency deviation of transmitters at frequencies of the modulating signal above the frequency f_2 at NU meets the following requirements:
a) at frequencies of the modulating signal in the band from f_2 to 6.0 kHz, the frequency deviation of the transmitters does not exceed the value A (Figure 1) measured at the frequency f_2. The upper frequency of the modulating signal f_2 is: 2550 Hz (for a frequency spacing between adjacent channels of 12.5 kHz); 3000 Hz (for frequency spacing between adjacent channels 25 kHz);
b) at a modulating signal frequency of 6.0 kHz, the transmitter frequency deviation does not exceed a value equal to 0.3 D_max;
c) at the frequencies of the modulating signal in the frequency band from 6.0 kHz to the frequency f_3, equal to the frequency spacing between adjacent channels, the frequency deviation of the transmitters does not exceed the values specified by the linear characteristic of the frequency deviation depending on the modulation frequency, which has a limit value at frequency 6, 0 kHz and a further roll-off of minus 14 dB per octave.
A graph of the dependence of the frequency deviation of transmitters on the modulation frequency is shown in Figure 1.
Figure 1. Plot of transmitter frequency deviation versus modulation frequency
Appendix No. 6
to the Rules for the use of subscriber
radio stations with analog modulation
mobile radio networks
Requirements for the parameters of the level of spurious emissions of transmitters
1. The level of transmitter spurious emissions measured at the external antenna connector at NU does not exceed the values given in Table No. 1.
Table N 1. The level of transmitter spurious emissions, measured at the external antenna connector, in the frequency band from 9 kHz to 4 GHz (for subscriber radio stations operating at frequencies up to 470 MHz) or in the frequency band from 9 kHz to 12.75 GHz (for subscriber radio stations operating at frequencies above 470 MHz)
2. The level of spurious radiation of the housing and structural elements of the transmitter of subscriber radio stations at NU does not exceed the values \u200b\u200bgiven in Table No. 2.
Table N 2. The level of spurious radiation of the housing and structural elements of the transmitter of subscriber radio stations in the frequency band from 30 MHz to 4 GHz
Appendix No. 7
to the Rules for the use of subscriber
radio stations with analog modulation
mobile radio networks
Requirements for the frequency deviation parameters of transmitters in transient mode
1. The duration of the transient processes of turning on (t_1) and turning off (t_3) transmitters, during which the frequency deviation of the transmitters from the nominal value does not exceed the frequency separation between adjacent channels (+- Delta f) depending on the frequency range, at NU does not exceed the values given in table N 1.
Table N 1
2. The duration of the transient process of turning on the transmitter (t_2), during which the frequency deviation of the transmitters from the nominal value does not exceed half the frequency spacing between adjacent channels (+-Delta f/2) depending on the frequency range, at NU does not exceed the values given in table no. 2.
Table No. 2
3. The temporary mask of the transient process when turning on the transmitter operating in the frequency range of 330 MHz or 450 MHz is shown in Figure 1.
Figure 1. Temporary mask of the transient when turning on the transmitter operating in the frequency range of 330 MHz or 450 MHz
4. The transient time mask for turning off a transmitter operating in the 330 MHz or 450 MHz or 800 MHz frequency range is shown in Figure 2.
Figure 2. Transient time mask when turning off a transmitter operating in the frequency range of 330 MHz or 450 MHz or 800 MHz
_____________________________
* For portable subscriber radio stations, the deviation of the transmitter frequency from the nominal value during t_1 and t_3 is allowed more than one frequency spacing between adjacent channels.
Appendix No. 8
to the Rules for the use of subscriber
radio stations with analog modulation
mobile radio networks
Requirements for the parameters of the radiation level of receivers
1. The radiation level of the receivers, measured at the external antenna connector, at NU does not exceed the values given in Table No. 1.
Table N 1. The level of radiation of receivers, measured at the external antenna connector, in the frequency band from 9 kHz to 4 GHz (for subscriber radio stations operating at frequencies up to 470 MHz) or in the frequency band from 9 kHz to 12.75 GHz (for subscriber radio stations operating at frequencies above 470 MHz)
2. The level of radiation of the housing and structural elements of receivers of subscriber radio stations at NU does not exceed the values \u200b\u200bgiven in Table No. 2.
Table N 2. The level of radiation of the housing and structural elements of the receiver of subscriber radio stations in the frequency band from 30 MHz to 4 GHz
Appendix No. 9
to the Rules for the use of subscriber
radio stations with analog modulation
mobile radio networks
Requirements for the frequency deviation parameters of transmitters of a subscriber radio station intended for data transmission
1. The frequency deviation of transmitters from the nominal value at NU does not exceed the maximum allowable values given in Table No. 1 of Appendix No. 2 to the Rules.
2. Deviation of the transmitter frequency from the nominal value at the EU does not exceed the maximum allowable values given in the table.
Appendix No. 10
to the Rules for the use of subscriber
radio stations with analog modulation
mobile radio networks
Requirements for the parameters of the duration of transients when turning on transmitters
Graphs of transient processes of changing the power and frequency of the carrier when the transmitters are turned on are shown in Figures 1 and 2.
At any point in time at NU, when the carrier power of the transmitters is greater than the steady-state transmitter carrier power (P_c) minus 30 dB (P_c - 30 dB), the carrier frequency remains within half the frequency spacing between adjacent channels (+-df_c) from the steady-state transmitter carrier frequency (F_c).
The sign of the slope of the section of the graphs "Power as a function of time", shown in Figures 1, 2, between the points (P_s - 30 dB) and (P_s - 6 dB) does not change.
For subscriber radio stations with an external antenna connector, the time intervals of transient processes of turning on transmitters t_p at NU are not less than:
For subscriber radio stations that do not have an external antenna connector, the time intervals of transient processes of turning on transmitters t_p at NU are at least 0.20 ms.
Figure 1. Graphs of transient processes of changing the power and frequency of the carrier when the transmitters are turned on, for the case when the duration of the transient process is given from the graph of changing the carrier power
Figure 2. Graphs of transient processes of changing the power and frequency of the carrier when the transmitters are turned on, for the case when the duration of the transient process is given from the graph of changing the carrier frequency
Appendix No. 11
to the Rules for the use of subscriber
radio stations with analog modulation
mobile radio networks
Requirements for the parameters of the duration of transients when turning off transmitters
Graphs of transient processes of changing the power and frequency of the carrier when the transmitters are turned off are shown in Figure 1.
At any point in time at NU, when the carrier power of the transmitters is greater than the steady-state carrier power of the transmitter (P_c) minus 30 dB (P_c - 30 dB), the carrier frequency remains within half the frequency spacing between adjacent channels (+-df_c) from the steady-state carrier frequency of the transmitters (F_c).
The sign of the slope of the plot plots "Power as a function of time", shown in Figure 1, between the points (P_s - 30 dB) and (P_s - 6 dB) does not change.
For subscriber radio stations with an external antenna connector, the time intervals of transient processes of turning off transmitters t_d at NU are not less than:
0.10 ms for frequency spacing between adjacent channels 12.5 kHz;
0.05 ms for 25 kHz adjacent channel spacing.
For subscriber radio stations that do not have an external antenna connector, the time intervals of transient shutdown processes t_d at NU are at least 0.20 ms.
Figure 1. Graphs of transient processes of changing the power and frequency of the carrier when turning off the transmitters
Appendix No. 12
to the Rules for the use of subscriber
radio stations with analog modulation
mobile radio networks
Requirements for the parameters of resistance of subscriber radio stations to climatic influences
1. Classification of subscriber radio stations, depending on the conditions of placement in terms of the impact of climatic factors of the environment, is given in the table.
| Group of subscriber radio stations | Operating temperature, .С | |
|---|---|---|
| Reduced | Increased | |
| Group B3 | -10 | +55 |
| Groups B4, B5 | -25 | +55 |
| Group H6 | +5 | +40 |
| Group H7 | -10 | +50 |
| Note: Designations of groups of subscriber radio stations: 1. B3 - transportable, installed in the interior of river vessels; 2. B4 - transportable, installed in cars, on motorcycles, in agricultural, road and construction equipment; 3. B5 - transportable, installed in mobile railway facilities; 4. H6 - wearable, placed during operation in the clothes or under the clothes of the subscriber, or in heated ground and underground structures; 5. H7 - wearable, operated outdoors or in unheated ground and underground structures. | ||
2. Subscriber radio stations remain operational when exposed to low and high operating temperatures given in the table.
Normal conditions (NU) - conditions defined as: ambient air temperature: from +15 to +35.С; relative humidity: 45 to 75%; atmospheric pressure from 650 to 800 mm Hg; power supply voltage - nominal with a tolerance of no more than + - 2%.
Extreme conditions (EC) - conditions for simultaneous exposure to increased (lower) operating temperature of the environment, given in the table of Appendix No. 12 to the Rules, and increased (lowered) power supply voltage, given in paragraph 15 of the Rules.
Appendix No. 13
to the Rules for the use of subscriber
radio stations with analog modulation
mobile radio networks
Requirements for the parameters of resistance of subscriber radio stations to mechanical stress
1. Subscriber radio stations are operational and retain their operating parameters after transportation in a packaged form under mechanical impacts in the form of shocks, with a shock pulse duration of 6 ms at a peak shock acceleration of 250 m / s2 (25g) and the number of shocks in each direction - 4000.
2. Subscriber radio stations wearable groups H6 and H7 are operational and retain their operating parameters after impact due to free fall from a height:
1 m for subscriber radio stations weighing up to 2 kg;
0.5 m for subscriber radio stations weighing up to 5 kg.
3. Subscriber radio stations are operational and retain their operating parameters when exposed to sinusoidal vibration with the characteristics of the influencing factor given in the table.
Table. Characteristics of sinusoidal vibration
Order of the Ministry of Information Technologies and Communications of the Russian Federation of April 12, 2007 N 46 "On approval of the Rules for the use of subscriber radio stations with analog modulation of mobile radio networks"
Registration N 9395
The duplex spacing of the receiving and transmitting channels in the NMT-450 standard is 10 MHz. The frequency spacing of adjacent channels is 25(20) kHz.
Since the total number of radio frequencies available in the system is limited, in order to increase the capacity of the communication system, the formation of small communication zones ("small cells") is envisaged. However, as a consequence, the probability of reaching the border of the service area of the base station to another, controlled by the same radiotelephone switch, increases. Moreover, the output power of the transmitters of all mobile stations is automatically reduced by the command of the radiotelephone switch when the station enters the "small cell" area.
The same power reduction procedure is used to reduce interference when mobile stations are close to base stations with normal service areas.
All signaling between the MSC and the mobile station is carried out over the communication channel. The call channel, on which all other mobile stations continue to receive, is ready to immediately transmit the next call.
During a call, the base station (at the command of the MSC) constantly emits a pilot signal (tone signal with a frequency of about 4000 Hz) and sends it towards the mobile station, which receives it and retransmits it to the base station. The received return signal is detected and evaluated by the base station. If the transmission quality (signal-to-noise ratio averaged over a certain period of time) makes this necessary, then the base station decides to connect another base station or to disconnect the call. The base stations send information about the results of the s/w ratio estimation to the MSC.
A typical set of channels at the base station: -6 communication channels -1 call channel. Repeat channels across two cells, i.e. the same channel can be used by two BSs separated by two cells.
2. The equipment of the BS (base station) consists of a base station controller and transmit-receive antennas (BTSS). Each BS has separate antennas for transmitting and receiving; Cellular networks use diversity reception. The BS controller (computer) controls the operation of the base station, as well as monitoring the performance of all units and nodes included in it. All BSs are connected to the switching center (CC) of mobile communications via dedicated wired or radio relay communication channels. The CC is an automatic station of the cellular communication system, providing all network management functions. PS - mobile station (subscriber radiotelephones).
Figure 12 - Scheme of a cellular network
S = 39462.6 km2;
The calculation of the radius of the service area R0, km is made according to the formula:
R0 = = = 112.105 km
The number of cells L can be determined by the formula:
L=1.21=1.21 
≈ 18 cells
The number of BSs is equal to the number of cells, since there is one base station per cell.
Cells are grouped into clusters. One cluster contains C base stations operating directly in non-repeating frequency bands.
The distance D between the centers of cells that use the same frequency bands is calculated by the formula:
D== 
== 39.5 km
radio system antenna telephone communication
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where is the frequency separation between the useful and interfering signals;
The level of the useful signal at the input of the receiver, which is taken equal to = 
;
- dimension matching factor.
If the useful signal level is not lower than 10 μV (20 dB), then, in accordance with the above empirical formula, the permissible level of the interfering signal can reach 143 dB (73+50+20=143 dB). Such an acceptable level will allow, in most cases, to ensure operation without interference from two neighboring radio stations located within the same service building of the NCC, but operating in different communication networks, and to install two stationary antennas in close proximity to each other on the roof of the building.
Thus, using the obtained empirical formula, it is possible to evaluate the EMC of radio facilities and determine the optimal frequency and territorial separations of radio stations operating in neighboring radio networks.
EMC calculation for two closely spaced radios
When carrying out a practical selection of the operating frequencies of radio stations in the case of installing two stationary antennas on the roof of one service building (NCS or CPR), the permissible level of the interfering signal is determined mainly by the output signal level from the transmitter of the interfering radio station (equal to 148 dB with an output radiation power of the transmitter of 10 W) and attenuation of the electromagnetic field between stationary antennas.
Specified: Attenuation coefficient per unit length of the antenna-feeder path of the transmitter and receiver of stationary radio stations;
the length of the antenna-feeder paths of the transmitter and receiver, respectively, and ;
transmitting and receiving antenna gain 
;
distance between 2 fixed antennas installed within the roof of the office building, r=6m.
It is required to select the ratings of the operating frequencies of two stationary radio stations located in the same service building of the NCC.
The permissible level of an interfering signal from a nearby transmitter is determined by the formula:
A=148-0.15 6+1.5-0.15 6+1.5-37=112.2.
The frequency spacing of the working channels of radio stations is determined by the formula:
At the final stage of the calculation, the choice of operating frequency ratings is carried out.
If one fixed station operates on a frequency 
, and the frequency spacing of the working channels was 
, then the operating frequency of the second radio station (second radio network) will be equal to .
EMC calculation of three radio networks
In the case of calculating the permissible level of interfering effect of the transmitters of two neighboring radio stations on the receiver of the third, it is necessary to consider third-order intermodulation interference. The results of experimental studies of the frequency dependence of the parameter of three-signal selectivity of receivers of radio stations of the types "Viola" and "Sapphire" showed that the assessment of mutual interfering effects between three radio networks organized at intermodulation incompatible frequencies is carried out based on the value of the three-signal selectivity of the receiver, equal to 70 dB. The level of the interfering signal at the input of the receiving device of the radio station is then calculated by the formula
where is the attenuation of the feeder path and the antenna gain of one of the two interfering transmitters;
dB - parameter of the three-signal selectivity of the receiver (admissible level of the interfering signal);
VI - correction, taking into account the allowable percentage of time (at the level of 10%) of the manifestation of interference in the combined frequency channel, is taken equal to VI = -5 dB.
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