Soviet E52 Koln copy R-310 “ Dozor”
Радиоприемник Р-310 "Дозор"

R-310 Dozor

Until the end of the 1950s, development and construction of military equipment in Germany was prohibited.
Soviets and USA continues to the develop the German technology in every filed where Germany was in advance respect the Allied: Aircraft, Rockets , Radio Electronics .

R-310 Dozor

In particular regarding the German radio project called ”Luftboden-Empfanger.-Programm” Soviets develop, in the early 50s, a new version of the E52 Koln receiver called R-310 “Dozor” (Радиоприемник Р-310 "Дозор") as reconnaissance and surveillance receiver. R-310 was produced, from 1954 to 1968 by Charkov Radio Works in Charkov Ukraine.
The performance of the receiver is however lower than its German predecessor despite the weight and size that where significantly increased: 66 kg against 40 kg of E52b Koln!

In the following table is showed the comparison of the main performance parameters

R-310 Dozor

The devices operate with a double conversion, in the lower frequency is used only one IF: 465 kHz. For higher frequency it use: first IF 1,235 MHz, second IF 455 KHz.
The following Table shows the similar frequency bands of R-310 versus the E52 Koln ones and the IF involved for each band: The selectable bands are 6. E52 Koln cover its frequency range in only 5 bands.

The radio is equipped with 15 direct heated tubes type 2SH27L (in Cyrillic 2Ж27Л ) . 2SH27L is a Russian replica of the American 1B4. The heater voltages are 2.2 volts and require a heating current of 57mA

E52 KolnR-310 Dozor

The different number of used tubes, "Koln" have 10 (RV12P2000 indirect heated tube), instead of 15, is an expression of different receivers conceptions. In The R-310 there is a double conversion with additional oscillator and a frequency multiplier for bands of III to VI
Even the front panel of the receiver reveals conceptual kinship with the German model.
In contrast to the "Koln", the R-310 has on the front panel a lot of larger number of controls, 9 knobs, and 5 switches 5, 3 buttons.
On E 52 was simplified the operation implementing essential commands in order to avoid errors by radio operator, mostly not technicians. For the Soviets, the R-310 was essentially used as surveillance and reconnaissance receiver where radio operators were only well-trained "technicians".
The construction philosophy is very similar to the Koln

Modular construction: each module are connected at the chassis by means of motherboard.

R-310 Dozor
R-310 chassis
E52 Koln
E52 Koln chassis

Only one type of valves removable directly form the front panel, without the necessity to remove the cover in order to simplify its replacement

R-310 DozorR-310 Front

Built in tube tester like E52a version. Like KWEA is possible to select the tube to be tested y means of a rotary switch

R-310 Dozor
Tube Tester

Compact power supply module with built in inverter in order to power supply the receiver by means of battery switch

R-310 Dozor
R-310 Power Supply Front
E52 Koln
E52 Koln Power Supply
R-310 Dozor
R-310 Power Supply Bottom

Optical projected frequency reading in order to set with more accuracy the frequency

R-310 Dozor
R-310 Optical Unit
E52 Koln
E52 Koln Optical Unit

Significant similarities between R-310 and E52 are also evident at RF antenna input. In both cases, it is equipped with connections for various antennas; it can be balanced antenna (impedance 100 to 400 Ω), asymmetric and verticals with 50 Ω.
The R-310, however have interesting Improvements: The antenna inputs can select by a switch at Front panel. A Variable capacitor, driven by a specific knob, can optimize the impedance matching of the antenna.
Another improvement concerns the use of a glow discharge tube to protect the receiver from the extremely strong RF input signals or atmospheric lightning voltages that are above their ignition voltage (see the RF section 08 in e 52).
Like the E52 Koln, Torn EB, KWEA the R-310 the band tuning coils are inside a rotating drum

.R-310 Dozor
R-310 Band tuning drum

The variable capacitor are, more or less the same as Koln !

R-310 Dozor
R-310 Tracking Preselector Variable Capacitors

E52 Koln
E52 Koln Tracking Preselector Variable Capacitors

The following three pictures show the compact designs of the oscillators. For the calibration of the first Oscillator there is an externally accessible trimmer, in the front which allows together with a quartz signal the frequency adjustment of the device to specified scale points. At E52 Koln the trimmer is less accessible because is situated in upper side.

R-310 Dozor
Variable first oscillator (6 of the right picture=variable capacity connected at the tuning knob)
R-310 Dozor
Second oscillator (2=2150 KHz Quartz;2=Ocillator Valve #7;3=770 KHz Quartz)

R-310 Dozor
BFO (5=455 KHz Quartz)

My Радиоприемник Р-310 "Дозор"

R-310 Dozor


  • Deutsche Demokratische Republik : KW-Empfanger R310M Manual DV-44/14
  • Wolfgang-D. Schroder : “Koln und R-310 Vorlaufer und Nacklange