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Neva   S-20
Body wearable covert radio

The S-20, codenamed NEVA 1 (Russian: С-20 НЕВА), was a body wearable covert transceiver that was developed between 1956 and 1958 in the former USSR for use by intelligence services such as the KGB [1]. The radio was manufactured by the Kozitsky Works 2 (Russian: Завод Козицкого) in Leningrad (Russia) and was used for agent communication during surveillance operations. It operated on a single tunable channel in the 148 MHz band using Amplitude Modululation (AM).
 
NEVA consists of a so-called body pack, a fixed remote control unit (RCU) and some accessories. The body pack is slightly curved, in a similar way to the radio direction finders of the era, so that it could easily be hidden under the clothing. It was usually carried in some kind of harness that also had space for the batteries and the vibrator.

A short piece of wire with a safety pin at the end was used as the antenna. It was commonly fitted inside the sleeve of a coat or inside the trousers. The unit is an interesting hybrid of valves (tubes) and semiconductors (transistors and diodes).
  
NEVA (S-20) covert body wearable transceiver

Development of the Neva radio set was started in 1956, with the first prototypes ready for testing later that year. Mass prodcution did not start until 1962, however. Nevertheless it is amazing that the Russians developed this radio with the transistor technology that had just become available, especially when considering that most people were still listening to tube-radios at the time. The NEVA shown here was manufactured in or around 1959, judging from dates on the components.
 
  1. Neva is a river in the North-West Russian Federation, flowing from lake Lagoda through St. Petersburg into the Gulf of Finland.
  2. This company was founded in Leningrad in 1953 as Siemens & Halske Telegraph Depot.
    It was renamed in the late 1930s to Works No. 210 [3].

NEVA (S-20) covert body wearable transceiver Connections at the top Top view Connections for battery, earphone and vibrator Serial number tag and sockets for Vibrator (B) and Microphone (M) Antenna connection at the bottom Remote control unit Operating the volume know

 
Controls
As the NEVA was intended for covert use, e.g. during surveillance operations, it has a minimum set of controls. In fact, there are no controls on the actual radio set itself, so that it can be hidden under the operator's clothing in some kind of body harness, together with a suitable battery pack.

NEVA covert radio and remote control

A suitable wire antenna is connected to the socket at the bottom of the radio, and attached to the clothing with a safety pin. The fixed remote control unit (RCU) is guided through the sleeve of the operator's coat, so that it can be carried in the hand. Microphone and speaker are hidden under the collar of the coat. An (optional) vibrator can be connected to draw the operator's attention in case his receiver is set to silent mode. The rather heavy batteries were also carried on the chest.
 
Batteries
In every portable (radio) application, power consumption and, hence, the battery requirements, are a serious challenge. On the one hand, the radio should be operational as long as possible, but on the other hand the batteries should be as small (and lightweight) as possible, so that they can easily be hidden under the clothing. Compared to later all-transistor designs, this problem was even bigger with NEVA as it features valves. And despite the fact that subminiature valves are used, they are still rather power hungry. As a result, big and expensive batteries had to be used.

NEVA was supplied with a bakelite battery holder that accepted three Silver-Zink batteries [2]. Like the radio itself, the battery pack was carried on the chest, in one of the pockets of the body harness. It was connected to the socket marked Б on top of the radio.
 
Remote control unit   RCU
The radio is entirely operated from a small handheld remote control unit (RCU) that holds the ON/OFF switch, a volume adjustment and a joystick-style Push-To-Talk switch (PTT).

The RCU is connected to the radio by means of a fixed multi-wire cable that is guided through the sleeve of the operator's coat, so that it can be carried in the hand from which it is operated.

When transmitting, the operator pushes the large rubber knob towards the right and speaks into the microphone hidden under his collar.
  
Remote control unit

 
Remote control unit Close-up of the text on the RCU Holding the PTT in the hand Power switch Volume knob at the rear Operating the volume know

 
Interior
Getting access to the interior of the NEVA is surprisingly simple. After removing just one screw from the bottom of the case, the entire radio can be extracted from it. When open, the radio remains fully operational. Note that the cable with the remote control unit (RCU) stays connected.
 
Inside the radio is a die-case aluminium frame with four compartments, two of which are hidden from view by metal covers. The image on the right shows the interior of a typical NEVA, of which the metal covers have been removed.

The radio is quite remarkable, as it contains semiconductors (diodes, transistors) as well as valves (tubes) in a single design. Subminiature valves are used for the transmitter and receiver stages (RF), whereas semiconductors are used for the audio section (AF) and the power circuit that provides the anode voltage for the valves.
  
Interior

Two large power transistors are also used in the driving circuit for the vibrator. The diagrams below should give a good idea of the location of the various circuits inside the radio.
 
Interior Bottom view Top view Miniature valves Frequency adjustment Detail LF section Manufacturing date: 1959

 


NEVA interior - top view


NEVA interior - bottm view


 
Technical specifications
  • Frequency
    148 - 149 MHz (single channel, free running)
  • Output power
    0.5 to 1 Watt
  • Modulation
    AM
  • Dimensions
    120 x 120 x 16 mm (135 x 120 x 16 with sockets)
Connectors
All sockets on the body of the NEVA radio are of the same type. They are used for the connection of antenna, battery, microphone, speaker and vibrator. Plugs for these sockets are extremely difficult to find, so we have specified their dimensions here:


 
Accessories
  • Antenna (wire)
  • Vibrator
  • Battery (block)
  • Remote control unit (RCU)
  • Earphone
  • Microphone
Help required
We are still looking for addtional information about this radio. In particular the operating instructions and technical description would be most welcome. We are also looking for the accessories and/or suitable plugs to fit the coaxial sockets on this radio. In case you have any of these items available, please contact us. Your help will be much appreciated.
 
References
  1. Takedown, Covert portable radio KGB secret service S-20 'Neva'
    Website Offtop.ru. Retrieved July 2016. 1

  2. Author: Admin, Security Service Radio and other 'stuff' (KGB)
    Retrieved July 2016.

  3. Radiomuseum, Leningrad Kozitsky Works
    Retreived July 2016.

  1. Thanks to Steven McDonald for bringing this link to our attention.

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Crypto Museum. Created: Tuesday 05 July 2016. Last changed: Thursday, 22 September 2016 - 15:20 CET.
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