Journal of Physics: Conference Series

Figure 6. Basic curves of radio wave propagation in the 160 MHz range for railway station conditions 
In real conditions, the values of the parameters of the radio communication system may differ from 
those for which the base propagation curves are plotted. To take into account these differences, 
correction factors have been introduced: 
B
p
 – coefficient that takes into account the difference in transmitter power from 12 W. Bm = 101g 
(12 / P
1
). For example, for one-watt transmitters, Bm = 10lg (12/1) = 10.79 dB; 
B
h
 = 201g25 / (h
1
h
2
) – coefficient taking into account the low location of the antennas of portable 
radio stations. Used only when h
1
h
2
<25 m2. In this case, the calculation of the communication range is 
carried out according to the curve corresponding to h
1
h
2
= 25 m
2
(Figure 6); 
G
1
, G
2
– gains of transmitting and receiving antennas, dB; 
B
f
= α
1
ℓ
1
+ α
2
ℓ
2
– coefficient taking into account the losses in the antenna-feeder paths of the 
transmitter and receiver (α
1
and α
2
are constant feeder attenuation, dB / m, ℓ
1
and ℓ
2
are the length of 
the feeders, m); 
В
c
= 8 dB – coefficient taking into account the field weakening by the contact network. It is used 
for electrified sections when calculating the communication channel between stationary and mobile 
(locomotive or wearable) radio stations; 
B
l
= 9 dB – coefficient taking into account the field weakening by the locomotive body when 
calculating the communication channel between the locomotive and any other radio stations; 
B
i
– coefficient that depends on the required reliability of the communication channel and takes 
into account the field weakening as a result of signal interference (Figure 7). 

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Intelligent Information Technology and Mathematical Modeling 2021 (IITMM 2021)
Journal of Physics: Conference Series