[ARC5] B-17 radios? I think not...

[Mike Morrow]

> What makes you think that the ATA sets were never fitted in the B17s?

The simple **complete lack** of any justification for, or evidence of, such
installations should be sufficient, I think.  :-)

> These particular ones most likely weren't,

They definitely were not, except maybe at Area 51. :-)

> but wouldn't early B17s have had ATA/ARA command sets

Navy gear did not appear in US Army Air Corpse (as our Educated Ruler
would say) aircraft.  Plus, early B-17s pre-dated the USN's 1940 ARA/ATA
command set, even if the USAAC had for some odd reason been inclined
to use USN equipment.  I doubt that the USN would have released its sets.

USAAC aircraft before 1941 carried SCR-*-183/283 command sets.  There
was a long and unsuccessful USAAC search for a better command set until
a reduced-scope slightly-modified version of the USN set was adopted
as the SCR-274-N in 1941 (about the same time USAAC became USAAF).

> or were they strictly used only by the Navy?

Strictly USN and Marine Corpse (as the Anointed One would say) use,
and possibly Coast Guard.  The later AN/ARC-5 was also a USN set
developed from the ARA/ATA (originally as ARA-2/ATA-3).  It too
was not used in USAAF aircraft during WWII...although the Bell
X-1 carried the AN/ARC-5 VHF set in 1947.

> My hybrid command set T19/ARC5/BC456/SCR274N setup includes an
> ATA antenna relay unit with the manufacture date clipped off...
> Didn't that have something to do with units produced for Lend
> Lease shipment to the Brits while we were still neutral in 1940? 

Not at all.  The presence of such information can be used by the bad
guys to help determine production rates.  There's no need for it
to appear on the equipment.  It's a contract date, not a manufacturing
date.  In some sense, that effort was defeated or abandoned in the
US Army Signal Corpse (as the All-Knowing One would say) with the
stamping of moisture-fungus proofing (MFP) date stamps all over the
gear.

Aside from that, I am unaware of any B-17s going to the UK in 1940
and 1941.

FWIW, the USAAC SCR-274-N is **electrically** identical to the USN
ARA/ATA except for the AF impedance of the receivers and the modulator
side-tone output.  The USN set used 300 ohm.  The USAAC set used 4000
ohm in -A models, and 4000 or 300 ohm in later models.

Also, there is nothing **electrically** interchangeable between the
ATA and SCR-274-N transmitter components and those in the USN's
AN/ARC-5 except the antenna relay and the modulator dynamotor.
(I address only proper military usage...all bets are off with hams.)

There is a pretty good but not too long article on these command sets
at http://en.wikipedia.org/wiki/ARC-5 .

In the history of one service using gear developed by another, the USN
in WWII used very commonly the SCR-269-* ADF, the SCR-522-A VHF-AM
command set, and ultimately for appropriate aircraft the RC-103-A
localizer and AN/ARN-5* glide slope ILS system.  The USN's ABK-* Mark
III IFF system was used by the USAAF with SCR-595-A as official
nomenclature, but the actual gear displayed USN name plates.  Similarly,
the USAAF's SCR-695-A Mark III/G IFF system was used by the USN with
ABF-* as official nomenclature, but the actual gear carried USAAC name
plates.  The USN's ZB-* VHF homing system became the AN/ARR-1 homing
adapter for both the USN and USAAF, but it was still referred to as
the "ZB" on in B-29 manuals and on actual controls.

Regardless...evidence for USAAC use of the ARA/ATA is non-existent.

Mike / KK5F