(c) 2000,2022 Peter McCollum

Selected Foreign Sets

This section documents certain non-U.S. equipment.


U.S.S.R. (KGB) BR-3U Transmitter and "Svir" Receiver

This radio equipment was part of a KGB "leave behind" program in Europe in 1966. It was buried in Switzerland, near Friburg, and 'booby-trapped' with explosives. Similar caches have been found in Italy, Belgium, and perhaps other countries.

In a 1966 article appearing in the CIA-internal journal "Studies in Intelligence", this radio set is described as follows:

"[this set] reflects the application of advanced technology to agent radios. It unquestionably represents a superior system of covert long-distance communications. It has a magnetic tape keyer for automatic transmission at a rate of either 450 or 750 words per minute [using frequency-shift keying]. With an output power of 80 watts and a frequency spread of 4.5 to 18 MC [4-20 MC for the receiver], it is eminently suitable for intercontinental traffic. Such a radio set reveals an extensive commitment of effort to clandestine operations and a high order of professionalism."

The article also mentions that the transmitter case measures about 4" X 9.5" X 13", and the total weight of the set is 33 pounds.


The BR-3U transmitter.


The receiver, code-named "Svir".


The accessories for the cached radio set.


The coder device used with the transmitter.


Three explosive charges in the lid; part of a "Molniya" device.


Another explosive charge inside the coder device.


Czech PR-35 Transceiver

The PR-35 is a body-worn FM transceiver made by Tesla in Czechoslovakia in the late 70's and early 80's. It was used by the East German Stasi, and probably several other security services. The most common frequency band is around 166 Mhz, although other versions operate at 152 and 170 Mhz, and also 70 Mhz. This type of set was used in surveillance operations to allow an operative to communicate discretely with others nearby.

The German-language manual is HERE. The last page lists various electrical specs for the set.


This view shows one of the basic configurations of the PR-35 set. At top is the transceiver, with the NiCad battery pack attached to the bottom, and the flexible rubber antenna mounted on top. At lower-right is a speaker, which can be attached under the collar lapel with the aid of a leather “schlinge” (loop) and a safety pin. At left is the “manipulator”, which includes a PTT switch and volume control. It is normally held in the pocket, so that it can be operated discretely. The oblong object at center-right is a vibration signaler. One of the mode settings on the transceiver supports a 1750 Hz signaling tone. Author's collection.

The right control selects one of three operating channels. The left control selects the modes: “0” = off, “K” = radiophone, “N” = 1750 Hz signal tone with speaker enabled (audible signal), “T” = 1750 Hz signal with silent vibrator indication.

These accessories are included with most versions of the PR-35 set. At left is a “bedienteil”, which is a speaker/mic with a PTT switch, volume control, and an LED battery indicator. At right is a battery charger adapter, and a wire antenna. This particular antenna's connector does not fit the standard PR-35 set – it may be intended for the 'civilian' version, which is similar but has a speaker mounted on the body of the transceiver.

The red dot next to the connector matches the red ring on the antenna connector. The color red indicates the 166 Mhz band, while yellow would indicate the 152 Mhz band. A third color indicates the 170 Mhz band. The screwdriver adjustment next to the channel knob is a squelch control.

The info on the bottom of the transceiver shows the serial number (upper-right), and the three channels. The calculation for converting the channel to frequency is: F = ((Ch*25) / 1000) + 147. So, these channels are 165.525, 166.000, and 166.050 MHz.

The inside of the PR-35 includes 13 transistors. The bolt-down transistor in the middle (with red paint) is presumably the RF final, while the TO-5 cased transistor to the right would be the driver. The marking on the filter(?) in the upper-left indicates that the IF frequency is 21.4 MHz (the 70 Mhz version of the set has a 10.7 MHz IF). There are seven crystals in the set, seen near the lower-left under pieces of brown foam rubber. The crystals are likely 3 each for transmit and receive; plus one that is probably for the base transmit oscillator.

Following are pictures of some additional PR-35 accessories. These items are not described in the manual for the basic PR-35 set. These photos are courtesy of T.B.

An external microphone.

A wireless behind-the-ear earphone, similar to a hearing aid. The white object in the center picture is a loop antenna/transmitter which is worn on the body (perhaps under the coat collar), and is connected to the PR-35 transceiver. The audio output from the transceiver is “broadcast” to the behind-the-ear receiver. This allows the wearer to discretely hear signals, but without the need for a wire passing between his ear and his clothing. On the right is a battery charger. An earlier U.S. version of this type of device is described in the book “Spycraft” by Wallace and Melton, pages 107-108.

A different type of “manipulator” for the PR-35 set. The plain rectangular item in the left picture is an “inductive sender”, presumably used with wireless earphones as in the previous pictures.


British Mark 119 Radio Set

This set is included here because it's overall size and specifications are very similar to the U.S. RS-1 / GRC-109 set.

MARK-119 British Radio Station Specifications







Power Supply


14 lbs 4 ozs

10 lbs 7 ozs

23 Lbs 8 ozs.


10-5/8" X 6-3/4" X 7-1/8"

10-5/8" X 5-3/8" X 6-3/4"

10-5/8" X 7-3/8" X 7-3/8"

Tube complement

EF 92 (6CQ6) RF amp

EF 91 oscillator X2

selenium rectifiers


EF 91 (6AM6) converter

2E26 final



EF 91 oscillator




EF 92 IF amp




EF 91 audio







Frequency Bands

0.5-1.05 MC

1.05-2.2 MC

2.2-4.7 MC


1.5-2.3 MC, 2.3-3.5 MC, 3.5-5.5 MC, 5.5-8.5 MC, 8.5-13 MC,13-20 MC


Power Output

100 mW

17 W, below 13 MC

14 W above 13 MC



The MK 119 receiver. Photo courtesy of Denis Chouinard.


The MK 119 transmitter. Photo courtesy of Denis Chouinard.


The MK 119 power supply. Photo courtesy of Denis Chouinard.


The complete MK 119 set. Photo courtesy of Denis Chouinard.


German SP-20 Transmitter

This modern German transmitter operates from 2-24 MC, with an output of 15 watts. The power supply accepts various AC or DC voltages (self-regulating), and has an internal battery.

An older version is the SP-15, which operates from crystal-control only.

Info from Louis Meulstee (PA0PCR):

This was manufactured by Pfitzner Teletron in W. Germany [the main contractor for the entire set] apparently in the late 70s-early 1980s (I am still tracing this) [transmitter S-6800 and antenna tuner ASG-6800 were made by Telefunken]. The indication on the harness box says KS30 (Kurzwellen Synthesizer 30) and KE30 (Kurzwellen Empfanger 30?) as type numbers [the KE30 is the matching receiver, but it is reported to not be in production - ed.]. There is also a connection for an external device KUG. The TX may be used without the synthesizer and has a crystal holder.

Please see my web-site on British Army radio equipment "Wireless for the Warrior" http://wftw.nl/b-one-default.html .


The SP-20 set. From the top, the units are: power supply; KS-30 synthesizer; ASG-6800 antenna tuner; and S-6800 transmitter. The key is in the left foreground. Photo courtesy of P.V.D.H.


Two more images of the SP-20 set, courtesy of Louis Meulstee.


The RT-3 coder used with the SP-20 set.



This is a pair of Dutch resistance crystal radios, built into a small metal can, and a matchbox. The image is from a postcard bought at a Dutch Resistance Museum in Amsterdam. The matchbox is marked in Swedish, but Swedish matches were sold in Holland for many years. Image courtesy of the late Bill Howard.