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

[Mike Morrow]

Mike Hanz wrote:

>I put a side by side schematic of the two C-38 variants at 
>http://members.cox.net/aaf-radio-2/C-38.GIF if you wish to compare.  
>This is also from the Nov 45 ARMN.

and

>C-38A Control Box:  To provide greater attenuation and control of the
>VHF audio output, modification of the C-38/ARC-5 control box has been
>directed by BuAer Technical Order No. 63-45.  The modified unit is
>designated C-38A/ARC-5.  

Thanks, Mike, for the info on the reason and nature of the changes made to the C-30 and C-38.  It's amazing what documentation you have!

One feature of the C-30A is that one can select a HF transmitter and still be able to determine and change the channel of the VHF receiver that's still feeding into the pilot's headset.  On the C-30, when a HF transmitter is selected, the VHF receiver remains on what ever channel it was last on, yet you can't tell by looking at the C-30 what channel that was.  Then, to change that VHF receiver channel, one would have to select for several seconds the desired VHF channel push button, then select the HF transmitter again.  On the C-30A, one can leave the HF transmitter selected, and just change the VHF channel switch to change receiver (and VHF transmitter) channels.

>Mike Morrow wrote:
>
>>Finally, has anyone ever come across a VHF antenna AT-8/AR...
>
>A drawing of it is shown in the ARMN - shows the same base as used for 
>the ARR-1 and ARR-2 antennas.

I'd like to add one to my AN/ARC-5 VHF set someday, if I can find one.  It would be easier to put in a display than trying to use the large wooden-masted AN-104 VHF comm antenna.

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.

73,
Mike / KK5F