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Tesla PR-35 (Stasi)
Body wearable surveillance radio

The PR-35 was a small body wearable radio (transceiver), produced by Tesla in Czechoslovakia. In was introduced in 1977 and was intended for covert operations and observation tasks. As it was used by the secret service of the former DDR, the Stasi, it is also known as the Stasi Radio.
The image on the right shows a typical PR-35 outfit. At the left is the radio. As it measures only 183 x 78 x 18 mm, it can easily be concealed under a person's clothing.

Microphone and speaker are separate or combined, and can be hidden under the collar of a coat. The cable to the separate push-to-talk switch (PTT) is led through the sleeve, so that the PTT can be held in the palm of the hand.

An external vibrator, with selective call, is present to warn the user for any incoming calls.

The radio operates in the 2-meter band (160 MHz) and has three fixed crystal controlled channels. All controls and connections are at one end of the radio, making it very easy to operate. There are two rotary switches, an antenna connector and an accessory socket. The first rotary switch is used to turn the unit on. It has 4 settings: O (off), K (traffic), N (selective call) and T (silent call). The second rotary switch has 3 positions and is used for channel selection.

A standard (helical) antenna is available with the PR-35 but, as it might attract too much attention, a short piece of wire is generally used instead. A wire antenna can easily be hidden under the user's clothing and is therefore part of the standard outfit. For special operations, especially prepared coats were sometimes used, in which the antenna wire was sewed in.

Between the channel selector and the antenna socket is a small recessed potentiometer that allows the squelch level to be set with a screwdriver. Volume control is not possible from the radio itself. Instead, the volume setting has been moved to the PTT unit held in the user's hand. It allows the user to control the volume with his thumb, whilst operating the transmitter with the index finger.
Release sticker Package contents The standard microphone with cable The complete external PTT (push-to-talk) unit with cable The speaker with short connection cable and leather strap Vibrator

Vibrator Separate PTT (push-to-talk) unit with volume control. Should be used with external miniature-microphone. Operating the external PTT (push-to-talk) unit The hand microphone with PTT (push-to-talk) and volume control Operating the microphone The speaker with short connection cable and leather strap Rear side of the speaker, showing the leather mounting strap Rear of the speaker, showing the connector

Grey helical antenna Black helical antenna Wire antenna Close-up of the connector of the wire antenna

Standard model
The PR-35 is based on a standard Tesla hand-held radio that is known by the same name (PR-35). As this can be confusing at times, we normally use the extensions Standard and Stasi to identify the model.

The Standard PR-35 is shown in the rightmost images below. It has a rather large speaker at the front and is usually fitted with a common helical antenna.

Standard PR-35 unit in original packaging Standard PR-35 unit in original packaging together with batteries, antenna and adapter. User instructions at the left. Standard PR-35 unit in original packaging Standard PR-35 radio with helical antenna (separated)

  1. Funksprechgerät PR-35, Kurze Bedienungsanleitung
    User instructions, Geheim (secret), 1977 (German)

  2. Funksprechgerät PR-35, Kurzbeschreibung
    User instructions, Geheim (secret), 1980 (German)

Other Stasi radios

Further information

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