ААНЗ.464414.001-03.61 РЭ p.46
Electronic Protection Measures (EPM) protect communications from hostile
interference using frequency hopping technique (FHSS mode). In this mode the operating
frequency of the transmitter changes hops so quickly, that it is difficult to intercept or jam the
radio signal. This mode allows additional data and voice protection, using technical masking
of the information. Synchronization is very important during the operation, in FHSS mode.
Synchronization is the process of conformance of operating frequency change, made by the
receiver and the transmitter, for extremely short periods of time. Temporal parameters of
synchronization are assigned manually or using the GPS system. In the
“type of operation
selection menu
” this is marked with “FHSS”. This type of operation is intended for operation
between the R-1150-00 radios only.
Note
– Frequency hopping technique, used by the radio, is implemented on the basis
of the STANAG 4444 recommendations.
Frequency hopping in the broad band is made between two, treble and bass,
frequencies, that limit the hopping band, which value is multiple of 10 Hz and 100 Hz.
Operating in this type of performance, it is possible to exclude some frequencies from the
hopping band, i.e., the radio will use not all frequencies between assigned limits of hopping.
While operating in the frequency hopping mode the Antenna Coupler can be used with
antenna in the following alternatives:
- Alternative 1. Broadband antenna is used. In this case the Antenna Coupler Unit
should’t be used.
- Alternative 2. Narrow-banded whip antenna, which length is from 4 to 6 meters is
used. In this case the Antenna Coupler should be connected and it must be adjusted together
with the antenna on the selected FHSS channel before the performance. The Antenna
Coupler should be tuned on selected operating frequencies in advance and all settings should
be stored in the memory of the Antenna Coupler.
Note - Frequency hopping is recommended to use, when the radio is operating in
stationary.
1.1.4.13 Synchronization in FHSS mode
Two or more radios that operate in the network in FHSS mode synchronize their single
performance. Synchronization provides usage of the same frequencies in the same period of
time by all radios. First, to ensure successful synchronization, the values of internal hours
readings (time of the day value) of all radios in the network should not have the difference of
not more than 90 seconds from the time value, set on the clock of the main radio, that provides