[Milsurplus] RTA-1B ftequency question

[Mike Morrow]

>However, two of the channels are in what in
>the US is a ham band, 3855 transmit and receive,
>and the other is transmit on 7248.5, but the receive
>frequency is split, at 7475.5.

Jack,

Only in ITU Region 2 are any of the frequencies you mention in ham bands.  In ITU Regions 1 and 3, the 80m band high end is 3800 kHz, and the 40m band high end has been 7100 kHz (but that's been recently relaxed).  Region 2 is all of the Americas and Greenland.  Regions 1 and 3 are the remainder of the world.

So your RTA-1B has been crystalled for use (at least on these channels) for flight outside of Region 2.

I can't address the split channel.  I've never heard of either frequency.

The RTA-1B most commonly encountered stateside is the AN/ARC-9 version, which comes with 10 specific channels whose frequencies are specified in the AN/ARC-9 manual.  Of course, no where on the unit anywhere does "AN/ARC-9" actually appear, but if it's got those orange SC stamps and has the frequencies stated in the manual, there is no doubt.

I find the RTA-1B to be interesting.  It dates from early WWII.  I have a commercial aircraft radio textbook from 1942 that shows one installed on a United Airlines aircraft.

Have you been able to find the virtually non-existent mount and control box???

73,
Mikr / KK5F