[ARC5] Jeeps with Radio Equipment

[Kenneth G. Gordon]

On 31 Jul 2021 at 16:43, Mike Morrow wrote:

> The radios may not be ARC-5, SRC-274 or ARA radios. They may be an
> earlier> look-a-like that ran on 12 volts.Rule that out positively. 
> There were no such radios anywhere anytime in military service...ever
> (except the R-148/ARC-5X and its rack... a 14 vdc version of
> R-23A/ARC-5).  When use of an aircraft MF/HF command set was required in
> a 12 vdc environment, the USAAF used the SCR-A*-183 and the USN used the
> appropriate RU/GF system.> Either that, or parts were scrounged and
> radios were heavily modified.This suggestion lacks credibility.The full
> SCR-274-N installation shown in Bill's photo looks like one pulled
> "lock, stock, and barrel" from a USAAF aircraft with no attempt to
> tailor it to just whatever HF capability that jeep may have required. 
> (Certainly it did not need a beacon band receiver.)  Just how great
> would be the motivation to locate ten rather uniquely configured 12 vdc
> relays of six different types, install them in five different
> components, rewire filaments in six different components, and rewire
> carbon mic excitation just to be able to install a stock-looking
> complete SCR-274-N in a 12 vdc jeep?  Occam's Razor indicates that the
> ONLY reasonable and logical conclusion is:  That SCR-274-N is being
> supplied 24 vdc.Mike's photo of a custom single receiver single
> transmitter installation provokes these comments:1.  The transmitter
> control box appears to have a built-in key on its top.  Only the ATA
> CBY-/CCT-23243 and SCR-274-N BC-451-A control boxes have a key...the
> very rare C-29/ARC-5 does not.  That indicates the equipment is ARA/ATA
> or SCR-274-N.2.  ALL components have black paint.  That indicates the
> equipment is ARA/ATA or EARLY SCR-274-N.It is equally unlikely that this
> equipment has been reworked for 12 vdc for the same reasons I cited
> above except that only six 12 vdc relays of six different kinds would be
> required.  Anyone performing such a quixotic feat should also have
> realized that a single-transmitter system using only VOICE emission
> requires NO transmitter control box.  Some post-WWII USN training
> aircraft used only the T-19, R-23A, and R-26/ARC-5.  There were C-125
> controls present for the R-23A and R-26, but the ONLY transmitter
> control was the instructor's PTT switch.My conclusion:  The sets in each
> of these photos without any doubt are being supplied 24 vdc.

I absolutely agree with this statement!!!

>  I will not
> speculate from where the 24 vdc comes.Mike / KK5F

Ha ha! **I** will! :-)

Ken W7EKB