The A model has module labels in Italian -
https://www.radiomuseum.org/forumdata/users/6435/mil_R-1051/Fig2_a.jpg
Also the A model has RF AGC OFF toggle switch near LSB PHONE knob, and a BFO Freq scale
I haven't found a front panel photo yet.

The 1978 USAF contract for R-1051C was made by Radionics - the photo shows grey front s/n 001 - I don't know if there were more from Radionics. All the other C models I have seen were black face made by General Dynamics, presumably earlier than 1978. The R-1051C was included in the AN/GRC-157 transceiver (1kw?).
As far as I can tell, there is no difference between B and C other than the black face.

Today's trivia - There was an attempt to get a UHF converter so the URC-35 and WRC-1 would work 225-400 mc - but I've never seen anything other than a BuShips Journal article -
https://www.navy-radio.com/journal/src30-xn1-6510.pdf

Cheers,
Nick England K4NYW
www.navy-radio.com


On Sun, Sep 25, 2022 at 9:22 PM Nick England <navy.radio@gmail.com> wrote:
R-1051C. USAF contract
https://www.navy-radio.com/rcvrs/r1051/R1051C-DSCN0128.JPG
And this one. What’s an “F” contract?
https://www.navy-radio.com/rcvrs/r1051/r1051C-430.jpg

USAF Manual Supplement for B and C

The 1051A was like a B but made by Elmer in Italy. I don’t have a manual for it. 

More photos at
https://www.navy-radio.com/rcvrs/r1051.htm

Cheers
Nick

On Sun, Sep 25, 2022 at 8:35 PM Robert Downs via Milsurplus <milsurplus@mailman.qth.net> wrote:

Has anyone ever seen an R-1051A/URR or an R-1051C/URR?  I have a bunch of different number manuals on the R-1051 but none say either A or C.  At least one says that it covers the base model and the B model but doesn’t mention the A.

 

Robert Downs

 

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