R-855UM radio was introduced in the Soviet Air Force and many
Warsaw Pact air forces at the turn of the 1960s and 1970s. The
Soviet experts examined the captured US-made examples of
survival radios and designed their own, all-solid state model.
The R-855UM operated on a single x-tal controlled channel in the
VHF airband spectrum, usually 121.5 MHz,
however there were other crystals available. It could provide AM
voice communications and MCW distress signal. Transmitter power
was to be no less than 0.13 Watt, the receiver comprised a super
heterodyne circuitry. During voice communications, the set
should provide up to 60 hrs work (1:3 tx/rx ratio), while in the
beacon mode, the battery lasted for 24 hours.
The R-855UM set comprised of two units: the TRx and the battery
connected with a cable. The transmitter (nomenclature JaJe
5.000.065) weighted 0.4 kg and measured 130x68x30 mm. It was
equipped with the Tx and Rx buttons, mode switch, microphone,
speaker and connectors for battery and antenna. The Hg-Zn
battery named Priboy-2S weighted 0.5 kg and measured 136x80x25
mm and was to be held in a survival vest or flight suit's
pocket. The set could also be worn inside a pouch with a strap
around the operator's neck.
were two antenna types for this radio available: a whip, which
provided up to 56 km communications range with a SAR aircraft
flying at 3000 meters, or a Komar-2M antenna (Kulikov type) with
an inflatable bladder to allow floating, which allowed up to 64
km communications range. The Komar-2M antenna could break under
some circumstances and the rings could be lost. Its sharp end
could also damage the airman's life raft when person was trying
to get inside, as it happened to a Polish AF pilot when he
ejected over Baltic Sea in the 1980s. Therefore, the whip
antenna was preferred.
R-855UM set could be used for ground to air SAR communications
and LOS ground communications with up to 1-km range between the
two sets. During a SAR mode, it could be used for voice
communications using its internal microphone and speaker or
using the aircrew headsets' or helmets' audio accessories. The
flight helmet's plug was connected to an auxiliary socket on the
cable linking the Priboy battery with the transceiver unit. The
following helmets could be used with the appropriate cable:
GSh-6A, GPSh-3, ZSh-3M and GSh-8A.
the 1990s many R-855UM's remained in service with the Russian
and the former Soviet Block air forces. Since the set is much
outdated, obsolete and not suitable for CSAR communications, new
radios will soon replace it.