USSR Covert FM radio
Chaika (Russian: ЧАЙКА), is a body-wearable simplex
developed in the USSR in the late 1970s.
It was used by the MKV 1 for covert surveillance operations, observations
and criminal investigations.
The radio operates
in the 150 MHz band and can easily be concealed under the operator's clothing.
Chaika (English: Seagull) is also known as 62R1
The radio consists of a main body unit (the actual radio) that is housed in
a curved plastic enclosure,
a hand-operated microphone,
an external speaker
and a wire antenna that can be attached to the clothing by means of
Chaika is powered by a
removable rechargeable NiCd battery that
is placed inside the main unit. The radio is normally supplied with an
extra battery, that can be charged with a separate battery charger,
whilst the other one is in the radio. Chaika is similar to other USSR
body-wearable covert radios, such as the Kaira.
The radio is supplied with two different handsets, known as Variant 1
and Variant 2. Variant 1 consists of a vibrator and a push-to-talk
switch (PTT). It can be carried in the pocket and uses an external
microphone/speaker. Variant 2 is an ordinary speaker/mike combination (no vibrator).
According to some people , Chaika was used by USSR secret services in the 1960s
and 70s. Judging from the components inside the radio
however, it seems more likely that they were used in the 1970s and 80s.
The device shown on this page was manufactured in April 1985.
Unlike the later Kaira and other covert radios,
Chaika does not have a voice scrambler,
allowing the device to communication with regular (non-covert)
MKV radios. The frequencies that were used for MKV equipment were carefully
chosen, so that they could not be picked up (accidently or deliberately) by
the regular police force. There are indications that the radio was also used
by plainclothes MKV operatives during the XXII Olympiad, also known as
the 1980 Summer Olympics in Moscow.
MKV = Ministry of Internal Affairs of the Soviet Union (USSR).
This includes the military police, regular public safety police, traffic
police (GAI), customs and interior troups (VV). Often confused with the
From the outside, the 62R1 (Chaika) is a fairly simple device. In order
to avoids mistakes during covert operations, there are no controls on the
body of the transceiver itself. Instead, all operations are controlled
by means of the remote control unit, of which there are 2 or 3 variants.
The transceiver has only one channel that is crystal operated and that
cannot be changed easily.
All remote control variants look like the device shown in the image on the
right. There are 3 buttons: a brown on/off switch at the right, a white
voice/tone switch at the top, and a spring-loaded
Push-To-Talk switch (PTT) at the left.
Variant 1 has a built-in vibrator that is activated when a 1750 Hz tone
is received. An external speaker is used as the microphone. This speaker
is fixed to the main body and can be fitted to the operator's cloating by
means of a safety pin.
With Variant 2, the speaker/microphone is built
behind the grille of the remote control unit.
The remote control unit shown here is a third variant. It has neither a
built-in vibrator nor a built-in speaker. Instead it just acts as a PTT for the
external speaker that is directly connected to the main body. In practice,
the Chaika transceiver was hidden under the operator's clothing, probably
under the right shoulder, with the antenna pinned-out horizontally
and the remote control unit accessible through the sleeve of the coat.
The speaker was hidden under the collar of the coat.
Chaika came with two identical batteries, so that one could be inside
the radio, whilst the other one was kept as a spare. The batteries are
made of very thin metal and can take 6 standard AA-cells of 1.5V each
(or 1.2V when rechargable NiCd batteries are used), giving a total of 9V.
The battery can be removed from the body, by
pressing the white button
towards the bottom of the transceiver and using gravity to get them out.
As the battery power is passed directly to the remote control socket,
the unit will not work when the remote control unit is not connected.
Chaika is a crystal-operated single channel 2-meter FM transceiver .
The device shown here operates at 148.250 MHz and was designed for an operational
range of approx. 800 metres.
The block diagram below illustrates its operation.
At the top is the transmitter with its varicap modulated 12.5 MHz oscillator
at the far right. The oscilator signal is first tripled and then doubled
twice. At the left is the HF driver stage, the PA stage and finally an
The lower part of the block diagram is the super-heterodyne receiver,
in which the oscillator is used twice: the basic frequency for the second
IF mixer and the tripled basic frequency for the first IF mixer.
After the 2nd IF amplifier, the signal is fed into the limiter/squelch
circuit and finally to a discriminator.
The LF output signal is amplified to speaker level and then fed to the
speaker/mike. Another output from the discriminator is used to drive the
Chaika is a complex device and is not very service-friendly. The transceiver
is housed in a die-cast plastic enclosure that is painted hammerite green.
The case consists of two shells that can be separated by removing 6 screws.
This allows one shell to be taken away. The other shell contains the
electronics. Both shells are sprayed with silver-paint to obtain
The image above shows the case-half that contains the electronics.
It is compartimentented in the same way as the
Each compartment contains one of the electronic circuits, but none
of the circuits can be removed easily, so we cannot show the PCB
- Frequency: ± 148 MHz (crystal operated)
- Temperature range (operational) 10°C - 40°C
- Humidity: 80% at 20°C
- Vibration: < 1.5 g
- Communication range: 800 m
- Weight: < 850 g
- Dimensions: 177 × 115 × 23 mm
- Power supply voltage: 6.5 - 8.4V
- Battery: 6 x 1.2V NiCd or NiMH - 6ZNK-0,45 (ЦНК-0.45)
- Output power: > 0.5 W
- Nominal frequency deviation: < 5 kHz
- Maximum frequency deviation: < 10 kHz
- Microphone input voltage: < 2 mV
- Distortion factor: < 15%
- Frequency fluctuation: +/- 30 · 10-6
- Harmonic suppression: 35 dB
- Current (during TX): < 350 mA
- Sensitivity: < 1.5 µV at 20 dB S/N ratio
- LF output power: > 30 mW
- Distortion factor: < 20%
- Frequency fluctuation: +/- 30 · 10-6
- Bandwidth (3 dB): < 28 kHz
- Adjacent channel suppression: > 60 dB
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© Crypto Museum. Created: Sunday 04 May 2014. Last changed: Tuesday, 13 June 2017 - 17:44 CET.