"K3HVG" ha scritto nel messaggio ...
You are quite correct. The Type 12 included two, 5-channel transmitters
in the VHF region and transverter for the MIL UHF band. The receive
output of the transverter went to (of course) the VHF receiver. I'll
also add that one earlier Type 12 receiver went from 118 to 148 MHz. At
my peril, here's a basic list for the Type 12:

R-10A receiver 520-1500 kHz
R-11A receiver 190-550 kHz
R-15 receiver 108-135 MHz
R-19 receiver 118-148 MHz
R-20 receiver 75 MHz (Mkr Bcn)
T-11A/b Trans. 116-132 MHz 5-channels
T-13A/B Trans. 132-148 MHz 5-channels
TV-10 UHF Transverter 228-258 MHz (8-channels in any 4 MHz wide band)
rx output to R-19 receiver (tunable).

ARC made a "Gonset" type portable package as one of the first FAC radio
sets. The later ARN-30 and 30D sets were used for VOR/ILS in acft up
into the late 60's. The ARN-30/30D included a B-10/13 VOR/ILS converter
and the IN-10 VOR/ILS indicator. There were probably over 25-30
different control boxes associated with the Type 12 series radios, never
mind the endless custom variations done by the ARC factory installations
group. Cessna Aircraft's acquisition of ARC ended ARC's renowned
quality....

One last comment, there was a genuine ARC-5 or SCR-274N receiver that
tuned the VHF aircraft band. It had the standard ARC-5-type front panel
dial, etc. They are rare as hen's teeth. I saw one in about 1959 and
none since!


Thanks Jeep,

continuing to browse the Internet, I found some pages stating that my R13B is equal to ARC type 12 receivers, others to type 15.

Anyway I believe that differences are not great, so, provided the tube set is the same, any diagram would do.

Presently I am stuck, as reverse engineering the diagram from the circuit would be way too time consuming.

Thanks and 73

Tony I0JX