[Milsurplus] Receivers for the ATD

[Mike Morrow]

>How many preset channels were their on the ARB?

None, the pilot had to manually tune to each channel.

But the ARB was the receiver most commonly used with the ATC until the post-war R-105/ARR-15.  The ATC had 11 channels.  Nevertheless, the ARB worked acceptably with the ATC.

>I would think the RAX is a good choice for the ATD, although the RAX
>has no provision for remote control looking at the construction of the ATD
>it appears to only have four preset channels, one in each band so if you
>have a rack of RAX receivers their can be one receiver for each transmitting
>channel.

I would not agree.  

The "channels" of the ATD, with the tuning units normally supplied, are:

A - 0.5 to 1.5 mc
B - 1.5 to 3.0 mc
C - 3.0 to 9.05 mc
D - 3.0 to 9.05 mc

The "channels" of the RAX-1, or tuning range of each receiver, are:

CG-46115 - 0.2 to 1.5 mc
CG-46116 - 1.5 to 9.0 mc
CG-46117 - 7.0 to 27.0 mc

It would be very awkward to come up with useful frequency combinations where the RAX-1 units could be used as if they were fixed-tuned AN/ARC-5 units.  And for the fixed-tuned concept to work, the RAX-1 local oscillators would have to have been stabilized such as the R-25 through R-27/ARC-5 units were.

Clearly if the "fixed-tuned" receiver concept were to be used with the ATD, it would be done using the much smaller, lighter, stabilized AN/ARC-5 units that were designed for remote control, and never with the RAX.  In fact, the employment of AN/ARC-5 fixed-tuned receivers with the ATC was a standard configuration described in the LF/MF/HF AN/ARC-5 maintenance manual.

There were C-131/AR auto-tuned R-26/ARC-5 units that were intended to serve with the ATC.  They didn't get much beyond the development stage.

>I have seen three ATD transmitters ... their were at least three produced

Doubtless, Bendix produced thousands of them.  It just looks like few got used.  If the ATC had not been developed, the ATD might have become the champion of WWII aircraft radios.  But the ATC was simply overwhelming.

Mike / KK5F