[ARC5] Soviet 1RSB-70 copy of the AN/ARC-8, Plus Other TU-4 Radio Sets

[Mike Morrow]

Most of us have heard about the Soviet copy of the AN/ART-13 and BC-348
(AN/ARC-8) liaison set, which the radio installation and operation manual
for the TU-4 calls the 1RSB-70 system, using the 1RSB-70 transmitter and
the US-9 receiver.

The 1RSB-70 copied the early USN ATC, not the USAAF T-47A/ART-13.
Principle differences between the 1RSB-70 and the T-47A/ART-13 are:

(1) 1RSB-70 has no dynamotor control power cover interlock,
(2) 1RSB-70 has no VFO dial B vernier scale,
(3) 1RSB-70 uses the original two-tube 8Q-1 type of MCW-CFI unit,
(4) 1RSB-70 uses the ATC-type six-band LF/MF oscillator (200 to 1500 kHz)
    which was a standard part provided with all early ATC COL-52286 units,
    rather than the three-band USAAF O-17/ART-13A LF/MF oscillator (200
    to 600 kHz) that was optional for the T-47A/ART-13.
(5) 1RSB-70 uses the original ATC-type slide rail mounting system,
(6) 1RSB-70 uses external LF/MF tank coils that are copies of ATC Navy
    Type 47281 (200 to 600 kHz) and Navy Type 47282 (500 to 1500 kHz).

**Not** coincidentally, those six attributes also describe exactly the
differences between the original early ATC system and the T-47A/ART-13.

I believe that the ATC design was most likely given to the Soviets by
the US, rather than the story about the Soviets copying the units on
board impounded B-29 aircraft.  Those B-29s would most likely have been
carrying USAAF T-47A/ART-13 units rather than the USN ATC, although
there remains some doubt since USAAF Radio Operator Information File
book photos in the liaison set chapter seem to show a USN ATC rather
than the USAAF's improved T-47A/ART-13.  Still, it seems unlikely that
a NT-47282 (CU-26/ART-13) would have been aboard a USAAF B-29 for the
Soviets to copy for their 1RSB-70.

The Soviet US-9 liaison receiver part of the 1RSB-70 system is a copy
of the BC-348-H/K/L/R.

Also interesting is the is the MF/HF command set carried on board the
Soviet TU-4 copy of the B-29.  It was...the SCR-274-N!  Not a Soviet
copy of the SCR-274-N, but an actual US-made SCR-274-N set with English
control labels that the radio installation manual for the TU-4 goes into
detail to explain to the Russian reader.  The US must have supplied
SCR-274-N sets to the Soviets under Lend-Lease in such quantity that it
was unnecessary to bother making a local clone.

Here's a list of other radio sets in the TU-4, from a 1950 Soviet manual:

                                 Soviet           US
System                           Nomenclature     Equivalent

MF/HF Liaison Transmitter        1RSB-70          ATC
MF/HF Liaison Receiver           US-9             BC-348-H/K/L/R
MF/HF Command Set                USAAF SCR-274-N  SCR-274-N
VHF Command Set                  12RSU-10         SCR-522-A
Interphone Set                   SPU-14           RC-36
Automatic Direction Finder       ARK-5            SCR-269-*
VHF Localizer Receiver           KP-RUSP-45       RC-103-A
Marker Beacon Receiver           MRP-45           Similar to RC-43-*
Radio Altimeter                  RV-2             Simplified AN/APN-1
Emergency 500 kHz Transmitter    AVRA-45          SCR-578-*

73,
Mike / KK5F