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Chaika   62R1 - ЧАЙКА
USSR Covert FM radio

Chaika (Russian: ЧАЙКА), is a body-wearable simplex covert radio, 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 (Russian: 62Р1).
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 safety pins.

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.
62R1 (Chaika) covert transceiver 148.250 MHz

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 [3], 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.
  1. 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 KGB.

Packaging Chaika with accessories in the original packaging 62R1 (Chaika) with accessories 62R1 (Chaika) covert transceiver 148.250 MHz 62R1 - Chaika Chaika body-wearable transceiver Connections and wires Battery and battery-release button

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.
Operating the Push-To-Talk (PTT)

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.
Remote control Operating the Push-To-Talk (PTT) Disconnecting the remote control unit Chaika with antenna and speaker Safety pin for attaching the antenna to the cloathing Battery and battery-release button Releasing the battery Removing the battery

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.
Using standard penlight batteries (AA-size)

62R1 (Chaika) with accessories Battery and battery-release button Releasing the battery Removing the battery Using standard penlight batteries (AA-size) Using 6 standard AA-size batteries

Circuit description
Chaika is a crystal-operated single channel 2-meter FM transceiver [2]. 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 harmonic filter.

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 external vibrator.
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 sufficient shielding.

The image above shows the case-half that contains the electronics. It is compartimentented in the same way as the circuit diagram. Each compartment contains one of the electronic circuits, but none of the circuits can be removed easily, so we cannot show the PCB component sides.
Interior Chaika interior Interior Close-up of the interior Interior detail Interior detail Interior detail Interior top view

Technical specifications
  • Frequency: ± 148 MHz (crystal operated)
  • Temperature range (operational) 10°C - 40C
  • 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
  1. Chaika Circuit Diagram
    Extracted from the original manual, 1985. Kindly supplied by [1].

  1. Karsten Hansky, Previous owner of the Chaika featured on this page
    Contribution May 2014.

  2. Unknown publisher, Chaika Circuit Diagram
    Extracted from the original manual, 1985. Kindly supplied by [1].

  3. Seller 'bugorr' on Ebay, 62R1 Chaika seagull, KGB USSR... offered for sale
    Retrieved April 2014.

  4. Radio Station 62R1 Technical Description and Operating Instructions
    Original Chaika Service Manual (Russian). Retrieved March 2015.

Further information

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Crypto Museum. Created: Sunday 04 May 2014. Last changed: Friday, 02 December 2016 - 09:47 CET.
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