R-123 Soviet Tank Radio Station
 

The R-123 is an FM radio station that was used in Soviet tanks until the fall of the Soviet Union in 1991. This was also one of the radio sets that was exported to all Soviet allies such as Iraq, Afghanistan, East Germany, North Korea, Cuba and Egypt. All R-123 units made for export were marked with English control labels. The US forces in Desert Storm and Operation Iraqi Freedom faced Soviet vacuum tube technology. The unfortunate Iraqi army, was equipped with radio sets of enormous and unnecessary complexity, with no spare parts and not much repair expertise. Both in Iraq and Afghanistan, the tankers were relieved to trade in their R-123 sets for modern and reliable American units.

Features:

  1. FM, ultra short-wave radio station.
  2. 20 Watt transmitter.
  3. Simplex and half-duplex telephony operation.
  4. Squelch control.
  5. 20.0 - 51.5 MHz frequency range divided into two sections (20.0 - 35.75 MHz, and 35.5 - 51.5 MHz). 1261 distinct usable frequencies separated by 25 KHz.
  6. Can be used with a 4 meter antenna at a speed of approx 20 MPH.
  7. Range is 20 KM without squelch enabled, and around 13 KM with squelch enabled while in motion.
  8. Stationary operation allows for a range of 40 KM during the day and up to 50 KM at night.
  9. Motorized station presets, where 4 stations can be set up along with their antenna matching settings. As the stations are switched to, the motors spin the mechanics to tune that frequency both on the radio set and the antenna matching system.

This radio station utilized 32 vacuum tubes of 5 different types: 1П24Б (2), 1Ж29Б (22) , 6Ж45Б (4) , 6Ж5Б (2), ГУ50 (2). Semiconductors are also utilized (transistors and diodes). Many design aspects were completely and unabashedly copied from German WWII designs (illustrated below).

This unit was very complex, both electronically and mechanically. The set was comprised of 7 modules:

  1. HF Stage
  2. Heterodyne
  3. IF Stage and AF Stage
  4. Front panel
  5. Antenna matching system
  6. Motors
  7. AF amplifier (duplex) and simplex/duplex system

The most expedient way to repair a failed module was to replace it, but with no access to spare modules, no wonder, Soviet allies were stuck with a virtually unserviceable radio station.

With the plethora of vacuum tubes in this unit, and the motors used for the station presets and the antenna tuner, the power supply had to deliver magic:

  • The BP-26 power supply delivers 8 voltages
    • 600 VDC (transmitter - anode)
    • 250 VDC (transmitter - screen grid)
    • 150 VDC (receiver - anode)
    • 6.3 VDC (receiver / transmitter - filament)
    • 1.2 VDC (receiver / transmitter - filament)
    • 150 VDC (simplex / duplex - anode)
    • 1.2 VDC (simplex / duplex - filament)
    • -150 VDC (negative bias for control grids)

 
The R-123 front panel. The receiver is in excellent physical condition. The English control name plates indicate this to be an export model.

 

 
This is the frequency pre-set control. It is completely stolen from the German WWII FuG-16ZY single-seat fighter radio station control, shown below.

 

 
The German WWII FuG-16 ZY single-seat fighter radio station. This radio set was used in all German WWII single-seat fighters such as the Me-109.

 

 
The frequency scale was an elaborate projection system that used a micro-film glass disc, lenses and mirrors. This was also copied from the German WWII E52b "Cologne" receiver of the Luftwaffe ground program. The same scale on the E52b is shown below.

 

 
The frequency scale of the E-52b. At the bottom right is the station pre-set knob - similar to the one used in the R-123 shown below. (courtesy Radio Museum)

 

 
The frequency pre-set control knob. It allows to switch to 4 pre-set frequencies and also for the receiver to function in "continuous" mode.

 

 
This small bakelite knob of German WWII manufacture, and was used to extract small vacuum tubes from their sockets. Here it works perfectly with the Soviet transmitting tubes.

 

 

 

 
The power supply BP-26. On top are the 4 fuses, in the middle is the power cable connectors to the R-123, and at the bottom is the earth connector and the +26 Volt connector. 2 fully charged 12 Volt car batteries can supply the power to this unit.

 

 
The non-tampering seal on the power supply. This power supply has never been opened since it was originally manufactured. I had to open it.

 

 
Some of the power supply circuitry. Notice the purple paint on the solder joints - this is to show evidence of tampering. If the joint was re-soldered, the paint would burn off.

 

 
With the cover removed, one can see the complexity of the mechanics in Block #4. Notice the glass disc behind the frequency setting dial in the center. This was the identical design to the German WWII E52b "Cologne" receiver.

 

 
Here is a glass disc from the "Cologne" receiver. Where are the patent infringement lawyers? (courtesy Helge Fykse)

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