[ARC5] R-25/ARC-5 Stabilized Receiver

[Mike Morrow]

>R-25/ARC-5
>
>NOs 74192  S/N 150
>
>This is a stabilized receiver with the S in a circle stamped on the chassis 
>near the tuning shaft..  How was this employed?

This was a "communications" receiver in the AN/ARC-5 system, along with the R-26 and R-27.  It was "stabilized" so that it could be pre-set and "lock-tuned" before flight.  The tuning capacitor shaft would be adjusted to an external calibrating signal, using the small tuning key that was always supplied with the three communications receivers attached under the tube cover.  Then the tuning key would be reversed and positioned to cover the tuning shaft.  The only control the pilot had was volume control, using either the C-38/ARC-5, or possibly but less likely, the C-27/ARC-5 control box.  Mode was fixed at MCW (no BFO control).

Of course, the R-25 could be connected instead to a C-26/ARC-5 or C-125/ARC-5 tunable receiver control box, but this apparently was not very common.

The corresponding transmitter is the T-18/ARC-5 (2.1 to 3.0 MC).  The AN/ARC-5 manuals state that normally one R-25 and T-18 were to be supplied for every five aircraft, while the other units were to be supplied one for each aircraft.  You can read more at:

http://en.wikipedia.org/wiki/ARC-5

You can find in the reference section of the above article the URL for the LF/MF/HF AN/ARC-5 Maintenance Manual (AN 16-30ARC5-2).

The R-23 (beacon band) and R-24 (broadcast band) receivers were "navigation" receivers.  They were NOT "stabilized" for they were never lock-tuned (no tuning key was supplied from the factory).  They were always connected to a tunable remote control like the C-26/ARC-5.

That's more than you really wanted to know, I'm sure!

Mike / KK5F