[ARC5] C-30 vs C-30A/ARC-5 and other small details

[Mike Hanz]

Mike Morrow wrote:

>Here's another minor ARC-5 mystery to me:  I have a couple of J-16/ARC-5 audio jack boxes the started out life as a J-22/ARC-5.  The J-16 and -22 are identical except that the J-22 has a relay that switches mic audio when the throttle switch is depressed.  I've never seen much reason for that relay, yet I wonder why the USN would re-work J-22s to J-16s, which involved removing the relay, filling the resulting holes, re-wiring internals, and altering the nomenclature tag.  There must have been some reason to go to all that trouble when a stock J-22 would seem to work interchangably with a J-16 as long as there was 28 vdc relay power fed to it.
>

Not sure why either, Mike.  To compound the mystery further, the ARMN 
has the following separate schematics:

J-16
J-22
J-22A
J-22B
J-22C

Each contains some minor difference from the others.  The last is a 
modification of the J-22B "to provide greater attenuation and less 
interaction of receiver audio outputs..."  It sez the mod was made 
"primarily to reduce the high level output of the AN/ARC-1 VHF 
equipment."  There are detailed instructions for the mod to a J-22B, 
ending with the requirement to change the markings on the box to J-22C, 
so something similar must have driven the change from J-22 to J-16.  
Quite likely it was a change in equipment connected to the jack box (no 
longer requiring the relay), but I don't have any documentation on that 
that I can pull up easily.

Best 73,
Mike