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Burst encoders
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R-354   Shmel - Шмель
Soviet spy radio set (Bumblebee)

The R-354 probably is the most widespread spy radio set deployed by the Soviet Union (USSR) during the Cold War. It was introduced in the mid 1960s as the successor to the R-350 and the R-350M and was used by most countries of the former Warsaw Pact, such as Poland, the DDR and Czechoslovakia. The radio was used by agents (spies) as well as by Special Forces (SF). It is also known by its codename Shmel (Bumblebee). In the late 1960s, it was succeeded by the R-353.
The radio is fully self-contained and is powered by a 6V (wet) battery that is stored inside the top lid. A short cable at the front panel connects the radio to the battery, giving approximately 15 minutes of life. Once the battery is exhausted, it can be re­charged with the hand-operated power generator that was also supplied with the set.

Alternatively, the radio can also be operated by another power source, such as the 6V battery of a car, or an external mains power supply unit (PSU). Suitable cables for this were carried in one of the pockets of the canvas manpack cover.

The receiver (left) and the transmitter (right) each have their own controls and frequency display, allowing split-frequency operation. A separate viewer can be fitted to the front panel to improve the readability of the projection scale. The supplied headphones can be connected to a two-pin socket on the left of the unit. A small light bulb on a flexible arm is present (right) to allow the burst transmitter to be operated in the dark. Both frequency displays are projection scales, altough a later version of the R-354 (modified by Tesla in Czechoslovakia) had LED displays.
Apart from small manufacturing differences, the following versions are known:
  • R-354
    This is the standard version of the radio set, as it was produced in the USSR, probably at the Proton factory in Charkov (Ukraine). This version has two projection scales for the RX and TX frequency readout.

  • R-354/CZ
    This is essentially the same version as the one above, but upgraded with a digital read­out. On this version the projection scales have been replaced with 7-segment displays and the black frame in front of the frequency windows has been removed. The modified radio still bears the model number 'R-354', but since the modification was done in Czechoslovakia, by Tesla, we have added the 'CZ' suffix, in order to distinguise it from the original one.

Standard version   R-354   Шмель
The diagram below shows the layout of the control panel of the standard version of the R-354. The control panel is normally covered by the top lid when the radio is in storage. After opening the top lid, the white power cable (6V DC) should be connected to the battery (which is mounted inside the top lid) or to an external 6V DC power supply unit, or to the 6V battery 1 of a vehicle.

The radio can roughly be divided into four sections. At the left is the receiver, which has its own tuning knob and frequency readout. AF output is supplied to a pair of headhones and the volume is adjustable. To the right of the receiver is the transmitter, which also has its own frequency adjustment and readout. At the right is the antenna tuning section and the burst transmitter. A small lamp allows the indicator to be read when operating in the dark. The lamp is mounted on a spring and is turned ON by releasing the spring from its storage position under the hook.
  1. When the R-354 was introduced in the mid-1960s, many cars still had a 6V battery.

R-354 in canvas cover with top lid open R-354 with top lid open Perspective view of the R-354 Film puncher, film and power cable, stored inside top lid Frequency tuning Close-up of the projection scales Burst transmitter Battery

Czech version   R-354/CZ   Čmelák
In the mid-1970s, some of the R-354 units that had been supplied to Czechoslovakia (CZ) were upgraded a with a digital readout, which took the place of the existing projection scales. The modification was carried out at the Tesla factory and consisted of a small unit, roughly the size of a Eurocard PCB (10 x 16 cm), and a 5-digit green 7-segment LED display. The black window pane of the old projection scales was removed and replaced by clear plastic windows as shown here:

In order to reduce power consumption - as the battery of the R-354 would not last very long - the LED display is only turned on when one of the calibration buttons at the top left are pressed. This also has the advantage that it does not reveal the position of station operated in the field.

After the modification, the name of the unit (on the name plate at the front) was not changed. The only way to tell the difference with the original version, is by looking at the frequency read­out. The name R-354/CZ is suggested by us in order to identify the modified Czech version.
R-354/CZ with top lid open Perspective view of the R-354/CZ in operation Close-up of the displays Checking the RX frequency Close-up of the working displays Close-up of the TX frequency Checking the TX frequency R-354/CZ under test

Sending messages in morse code
Built-in burst keyer

Like its predecessors, the R-354 can only send messages in morse code, using the integrated morse burst encoder at the front right of the radio. The morse unit, that can be recognised by the numerical key pad (0-9) and the manual morse key, is bolted onto the front panel of the radio.
There are three ways for sending messages in morse code. (1) The first method is by using the small black morse key just above the key pad. Messages can be sent directly, but this was only used in case of an emergency. Furthermore, the key is not very comfortable, making it rather difficult to send morse messages faultlessly.

(2) If the operator was not trained in giving morse, he could use the number keys to send a pre-coded (numerical) message, simply by typing the appropriate numbers. In case of a mistake, the user would press the ······ button.

(3) The normal mode of operation however, was by using the built-in morse burst transmitter which allowed pre-coded numerical messages to be sent at very high speed, minimising the risk of interception and radio direction finding. For this, the messages were first stored on photo film as a series of punched holes, much like with the R-350 radio set. Standard 35 mm photographic film was used for this purpose, as it was readily available in most countries around the world. Agents in the field could buy 35 mm film in virtually any store without attracting any attention.

Unlike the R-350 however, the R-354 consumes only half the amount of film, as the film was first sliced in two halves (of 17.5 mm each) using a supplied film cutter. Once sliced, the film was fed through a puncher, which punched a pattern of holes in the film, each representing a number (0-9). Two different versions of the film puncher have been identified: a large one and a small one.
The full radio set with opened lid Close-up of the burst encoder The film container (stored inside the top lid) Both film and cutter are stored inside the container The cutter that was used to slice the film in two halfs The radio in full operation with the hood over the frequency readout

Audio samples
Below are some audio samples of the R-350M, recorded by collector Karsten Hansky in Germany in June 2014 [2]. The radio was connected to a dummy load and an ELAD FDM-S1 was used to receive and record the signal. Further sound processing was done with Audacity (software).

The R-354 was usually supplied in a canvas cover with two shoulder straps that allowed it to be carried on the back. It was typically used in this configuration by military personnel, and Special Forces (SF) in particular. The manpack cover has various pockets in which the common supplies and accessories were stored. Additional spares and accessories were available separately.

35 mm photo film for recording the message Film cutter or slicer Film puncher (old model) Film puncher (new model) 6V wet battery battery extension lead Battery cable
Viewer for the frequency projection scales (standard version only)
Small spares kit Large kit with spares, accessories and supplies Mains battery charger Crank operated power generator Headphones Wire antenna Two fibre masts for wire antenna Manpack raincoat for R-354
Parachute bag for dropping off R-354 User manuals, maintenance reports and technical documentation

One of the most brilliant features of the R-354 is the fact that ordinary 35 mm photographic film is used for the burst transmitter, just like on the earlier R-350 spy radio set.

A cylindrical metal can with many metres of 35 mm film is supplied with the set and is usually stored inside the top lid of the radio. This should be sufficient for hundreds of short messages. The image on the right shows a fully loaded film can. If more film was needed, the agent was able to buy it anywhere in the world, without raising any questions. After all, it was common film.
35 mm supplied in metal can

Unlike with the earlier R-350 spy radio set, only half the width of the film is needed on the R354. This means that the operator can send twice as many messages with the same film supply. It also means that the film has to be sliced in two halves before it can be used.

An appropriate film slicer was supplied with the radio set and was usually stored inside the film can. For this reason, one side of the film can is bulged somewhat. The image on the right shows how the slicer is used to split the film in two.
Cutting the film

Film can Metal can with 35 mm film and cutter Inside the film can Film in can and film cutter 35 mm supplied in metal can Cutting the film Cutting the film Cutting the film

Film puncher   old model
Initially, the R-354 was supplied with the film puncher shown here. It is a rather buly square device that is normally stored under a flap in the top lid of the radio, aside the film container.

The film is fed through the puncher, and a pen is used to enter the digits of a pre-coded message on the rotating disc, much like dialling a number on an old rotary telephone. Each number is represented by a series of holes (rather than a single hole, as on the R-350).

Old style burst encoder Old style burst encoder Instruction sheet showing the various codes The pen stored inside the unit The two halves of the pen The fully assembled pen The puncher stored in the top lid of the radio, aside the film container

Film puncher   newer model
The rather bulky film puncher shown above, was later replaced by the much smaller one shown here. It fits nicely in one hand and is stored in the usual bay of the radio's top lid.

Punching the message works much like a dymo label printer. The wheel is set to the required number, after which the large white button is pressed. Each number is represented by a series of holes. A small copper blade, hidden behind the black instruction plate, can be used to clear the mechanism when it gets blocked.


The R-354 was supplied with a so-called 6V 'wet' battery that was stored inside the top lid of the radio, in such a way that the radio could be connected to it by means of the short 6V DC cable running of the front panel.

As the R-354's transmitter is rather power-hungry, it can only be operated for a short period of time, typically just 15 minutes, before the battery has to be recharged again. For this reason, the R-354 was often supplied with a hand generator, so that the battery could be recharged between two sessions.

Extension lead
A short extension lead was supplied to allow the radio to be connected to an external power source, or to connect the battery to a charger.

The extension lead is only about 50 cm long and has a two pin male plug at one end, and a matching female plug at the other end. The lead is either stored inside the manpack cover, or in the top lid of the radio, in which case is was wound around the film container.

Battery charger cable
The battery of the R-354 lasted only a few minutes before it had to be recharged again. Recharging was usually done with a hand generator or a small mains charger.

Alternatively, the battery could be charged from a standard car battery, using the supplied battery charger cable shown on the right.

As the projection scale of the R-354 produces a rather faint image, a foldable hood was supplied that could be fitted in front of the display, thereby effectively blocking any sunlight.

The hood was normally folded and stored inside the large pocket of the back pack (at the rear). The images below show how the hood was used. It was mounted over the display in such a way that both frequency adjustment thumbwheels were left free. Note that the viewer is not present on the Czech version of the radio (R-354/CZ).


Small spares kit
Sometimes a small plastic box with some spares (consumables) is supplied with the radio. If it is present, it is usually packed inside one of the pockets of the back pack.

The box contains several light bulbs, fuses and a piece of insulation tape. As far as we know, the boxes were either black or white (see below).


Spare parts and accessories
Some R-354 radio sets were supplied with a small bakelite box containing a number of spare parts, accessories and consumables. A checklist, glued inside the lid of the box, shows which items should be present. Please note that at least two different layouts of the spares box exist.
The box shown here contains the following items:
  • 4 rechargable batteries
  • Battery fluid (container)
  • Hex key
  • Syringe
  • Spare valves (tubes)
  • Mains battery charger

The closed box The opened accessory box One of the wet batteries Battery fluid (Potassium Hydroxide) Hex key for (dis)mounting the battery connections Syringe for filling the batteries Spare miniature valves Mains battery charger

Mains battery charger
A rather small mains adapter was supplied with the accessory kit (shown above). It's a small grey cubical box that can be plugged straight into a mains socket.

At the back of the unit is a standard mains socket that allows a common mains light bulb to be connected. When connected to the battery, the lamp acts as a current limiter.

Mains battery charger Mains battery charger (bottom view) Inside the battery charger Inside the battery charger Inside the battery charger Inside the battery charger Drawing of the charger

Power generator
If no mains power is available, the battery can also be charged with a small crank-operated power generator. Charging the batteries is not an easy task and takes several hours, for just a few minutes of operation.

The generator is normally stored inside a carrying case with a canvas strap. The power cables are stored inside the top lid of the case. New generators were generally supplied in grease paper, stored inside in a green wooden box, together with a checklist and instructions.

Wooden box containing the generator Checklist The generator packed in paper Connection cables stored inside the top lid The closed generator The generator taken out of the carrying case The hand-crank operated generator The hand-crank operated generator

Almost any type of headset can be used with the R-354. In most cases, a common USSR military headset was supplied, with rubber ear pads and elastic head bands. Such headsets are commonly used with military radio sets in tanks etc., as they can be worn under a helmet.

The headsets is connected to the two-pin socket on at the far left of the radio's front panel. Some sets were used with a small earpiece such as the one shown below.

Carton with new headset Unpacking the headset The standard headset (normally stored in one of the pockets of the backpack) Alternative earpiece Alternative earpiece

For proper operation of the transmitter and the receiver, it is important that a long wire antenna and a suitable counterpoise are connected to the radio. A suitable wire antenna is supplied with the set and is usually stored inside one of the pockets of the manpack cover.

The image on the right shows the antenna that was typically supplied with the set. It has a nylon fishing line with a throwing weight at the end, that allows the antenna to be fitted in between two trees easily. Instruction for setting up and tuning the antenna are provided in the manual.
Wire antenna with throwing line and weight

Antenna mast
To ensure that the antenna wire is as free as possible from ground and obstacles, one or two supporting masts are supplied with the radio. These masts are usually stored inside a canvas bag that is strapped to the bottom of the radio.

The mast is constructed of glass fibre and consists of several telescopic segments. It is light weight and can be erected in seconds.

When the R-354 was used in a military context, which was usually the case, it had its own canvas 'raincoat' with pockets for the accessories. It has two strong shoulder straps that allow the entire radio station to be carried on the back.

The canvas raincoat also protects the radio against the environment and is padded to make carrying slightly more comfortable for the radio operator. The image on the right shows a typical canvas manpack cover. It is attached to metal nails on the circumference of the radio.
Canvas manpack cover

Parachute bag
Provisions have been made to allow an R-354 radio station to be dropped-off by parachute. This was considered useful when supplying army troups, Special Forces (SF) (operating behind enemy lines), resistance groups and agents.

The image on the right shows a typical R-354 parachute bag in exceptionally good 'as new' condition, with all of its padding still intact. In practice, the padding of the surviving parachute bags has commonly decomposed after many years of storage.
Parachute bag for dropping an R-354 spy radio set

Each R-354 was supplied with a set of manuals, complete with user instructions, circuit diagrams and maintenance information. In some cases, maintenance logbooks or passports for the radio and the batteries were also present.

In practice, original manuals in the Russian language are extremely rare, but thanks to Bjorn Forsberg [A][B], we now have them available:

 Download manual
 Download circuit diagrams

Although the R-354 is rather heavy, it is a well constructed electronic hybrid that shows the clever combination of valves (tubes), transistors and digital building blocks. After loosening the four large bolts at the sides of the front panel, the radio can be lifted from its enclosure.
All building blocks are mounted to the front panel, so that the radio remains fully operational when being serviced. At the top are a tuning capacitor, a band selector, the antenna tuner and part of the power supply. Left of the center are the two projection scales. At the far right is the digital block that holds the burst transmitter.

At the bottom are the smaller electronic circuits, like the various stages of the receiver. Although transistors are used at various places inside the R-354, some of the more critical circuits are still built around sub-miniature values (tubes).

The radio is beautifully compartmented, using a die-cast aluminium alloy frame to hold the various circuit boards at the bottom. Also at the bottom is the remaining part of the power supply. To the left of the power supply is the transmitter PA-stage, consisting of three sub-miniature valves connected in parallel. At the far right of the front panel is the key panel with its integrated film reader. Behind the switches is a nice die-cast assembly with the micro switches.

To the rear of the film reader is the actual burst transmitter that is housed in a large rectangular aluminium sub-assembly. Inside the block are 27 small PCBs, each of which contains a digital circuit. The block connects to the film reader by means of a 31-pin connector at the front.
Czech version
The Czech version of the R-354 is largely identical to the standard version. In fact is is a standard version which was modified at the Tesla factory [3] in the mid-1970s. As part of the modification, the projection scales were removed and their space was used to accomodate a digital readout.
The modification consists of a brass box that is fitted in the space that was previously used by the projection scales. A large power transistor and a relay are fitted to the rear of the box. The box is open at the front, so that the displays are visible though the windows in the front panel.

The circuit is mainly built with Tesla parts, such as the MH5400 series ICs, which are the military variants of the well-known 7400 family [4]. In order to reduce power consumption, the displays are disabled by default and the user has to press one of the calibration buttons to enable them.
Digital readout circuitry

Pressing the upper calibration button will cause the display to show the current receive frequency (RX). The left window will show the MHz part of the frequency, whilst the kHz part will be visible through the right window. In the same way, the lower calibration button should be pressed to monitor the TX frequency. The TX and RX frequencies are both free running and can be altered in the usual way by turning the dials below the display. The display is merely a frequency counter.
Top side of the radio Bottom side of the radio The projection scales Various electronic circuits Power section Unit with digital building blocks Close-up of the digital building blocks Unmantled burst encoder
Czech version interior Tesla frequency readout fitted in the space of the former projection scales Tesla frequency readout (closed) Digital readout circuitry Rear view of the displays Detail Relay and power transistor fitted to the back of the unit Top view of the frequency readout

Technical specifications
  • Power Supply: 6 Volt, 3-8 Amp.
  • Frequency range: 2.5 - 15 MHz (in 5 ranges)
  • Modulation: A1A, A3A
  • TX Power Output: 10 Watt (CW)
  • Range: 1500 km
  • Weight: 12 kg
  1. Radio Station R-354, User and maintenance manual (35.2MB PDF)
    Original documentation supplied with the R-354 (Russian). 1970. 1

  2. R-354 Circuit Diagrams, large format (1.1MB PDF)
    1970. Extracted from [A]. 1

  1. Louis Meulstee, R-354
    Wireless for the Warrier. Volume 4. September 2004. ISBN 0952063-36-0.

  2. Karsten Hansky, Sound samples of R-354 transmitted signals
    Germany, June 2014.

  3. Wikipedia, Tesla (Czechoslovak company)
    Retrieved July 2016.

  4. Tesla ICs, TTL types and marking
    Website. Prague, Czech Republic. Retrieved July 2016.

  1. Original scanned manual kindly supplied by Bjorn Forsberg.

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© Crypto Museum. Created: Friday 04 December 2009. Last changed: Sunday, 02 October 2016 - 08:31 CET.
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