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MOST radio (modem)

The MOST radio (radio modem) is designed for digital data exchange via radio channel in a simplex and (or) half-duplex mode.


  • exchange of data packages
  • telemetry with a bidirectional data flow
  • signaling systems
  • remote control of distant objects
  • control systems for production, transport industry


The radio is connected to peripherals via RS-232 standard serial port. Power cables and antennas are connected to jacks on the modem rear panel. Metal housing ensures high level of protection against external disturbance. Transceiver and power modules are rigidly attached to one another.

The radio (radio modem) has a wide range of service functions that increase its performance characteristics: measurement and data output of input signal status, voltage standing-wave ratio of an antenna-feeder device, supply voltage, temperature inside the transmitter housing, etc.

MOST radio (radio modem) modifications

Modification   Configuration Frequency band, MHz Power supply votage, V Weight, kg Dimensions, mm
MOST-M/MOST-MM automobile version  PP-D/PP-М 450—470/ 146—174 13.2 1.7 ±0.2 220x230x48
MOST-М1/MOSТ-ММ1 locomotive version PP-D/PP-М, BP 48/12 V 48.0 4.1 ±0.3 280x240x97
MOST-S/МOST-SМ fixed version PP-D/PP-М,  BPS 220/12 V 220.0 7.3 ±0.3 280x230x171
MOSТ-S1/МОSТ-SМ1 fixed version PP-D/PP-М, BPS 220/12 V* 220.0 7.3 ±0.3 360x230x171
МОSТ-L locomotive version PP-ML, BP 48/12 V 146—174 48.0 4.1 ±0.3 280x240x97
МOSТ-V van version PP-МV 13.2 1.3 ±0.2 206x142x60
МОSТ-МL automobile version PP-МL 13.2 1.7 ±0.2 220x230x48
МОSТ-SL fixed version PP-МL, BP 48/12 V 220.0 7.3 ±0.3 280x230x171
МОSТ-SL1 fixed version PP-МL, BPS 220/12 V* 220.0 7.3 ±0.3 360x230x171

* — with the RS-232/RS-422 interface converter board

Parameter Value
Transceiver operation mode simplex and (or) half-duplex
Frequency band:
— «PP-М» 146—174 МHz
— «PP-D» 450—470 МHz
Data rate 9600 bit/s
Minimum frequency spacing 25 kHz
Transmitter output power 5; 10; 20* W
Probability of invalid bits reception at 2 µV input and 9600 bit/s rate, (PP-М and PP-D), not worse than 1х10-6
Probability of invalid bits reception at 0.7-2 µV input and 9600 bit/s rate, (PP-МL and PP-MV), not worse than 1х10-6
Probability of data set delivery in noise free mode at 2 µV input and 9600 bit/s rate (PP-ML and PP-MV), not worse than 0,9999
Number of channels up to 16
Modulation GMSK

* — other 3 values can be programmed within 3—30 W

Operating characteristics

Parameter Value
Operating temperature range –40…+60 °С
Storage temperature –50…+70 °С
Time to failure 40000 h
Average lifetime, up to 15 years

PP-3U transmitter
PP-3U transmitter is compatible with protocols of PP-ML transmitter but has smaller dimensions, mass, power consumption and the possibility of choosing communications interface.

МОSТ-3U radio modem
МОSТ-3U radiostation consisits of transmitter PP-3U and locomotive radio components supply unit, it is compatible with protocols of MOST-L radiostation.