Tony, What you have is the receiver for the ARC Type 12 radio system.
The military called the system the AN/ARN-30. They look very much like
command sets but are not interchangeable (racks, etc.). I have all the
books for the Type 12 system up to, and including, the
crystal-synthesized ARN-30D. I will scan the receiver schematic for you
and send it out ASAP. BTW, the Type 12 is designed to be set up for
either 12 or 24 volts, via filament jumpers. 24v ARC-5 dynamotors will
work with Type 12 equipment. Back to you later.
de Jeep/K3HVG

Antonio Vernucci wrote:
I have a receiver looks the same as the well known command receivers (BC-453, BC-454, BC-455), but has the following main differences:

- it is grey instead of black
- it works at VHF (108-135 MHz) instead of HF
- it has loctal tubes (14A7, 14R7, 14F7) instead of octal tubes (but has one 12A6)
- it also has some miniature tubes too (9002 and 9003)
- it is built by Aircraft Radio Corporation (ARC)
- it is marked R-13B but it should be nearly identical to the R-15/R-509, and similar to the R-19/R-508/R-507

I searched the Internet for the schematic diagram with no success. Does anyone have it and would available to make a scan for me ?

Thanks and 73

Tony I0JX