[ARC5] SCR-274 System

[Mark K3MSB]

The CW Key on the BC-451-A was never intended to be a CW Key like the J-37
or J-38.

On the B-17 the BC-451-A was mounted on the pilot's overhead console and
the pilot would have to reach his hand up and hold it in by pushing
forward.  Not conducive to sending any messages other than perhaps SOS.

On the B24 (D Model) the BC-451A was located on the console between the
pilots.  You could certainly send a message using the built in CW key, but
again, not conducive to any message other than perhaps SOS.

I do a lot of WW II Aviation reading and for years I've been trying to find
at least one solid reference that a Command Set was used on CW during a
mission.   So far I haven't (still looking).  I've noted passages which
could indicate such, but nothing definitive.

Last year I attended an on-line CAF seminar by Tom Culbert author of the
book “Pan Africa – Across the Sahara in 1941 with Pan Am” by Tom Culbert
and Andy Dawson.  A very good book about the USAAF contracting with Pan Am
to improve the existing  Imperial Airways Route across Africa in 1941.

I purchased the book and found the following on page 105:

“Some radio operators used SCR-274 Liaison Radios, that were installed in
the aircraft to practice their “ham” radio skills.  Using their personal
call signs and jargon, they could shoot the breeze with their friends and
colleagues from Liberia to Cairo.  PAA_Africa received word that the
British were very concerned about the strange transmissions near 2
megacycle frequency, and the practice was stopped”.

I subsequently emailed Mr Culbert with the following question:

“In the paragraph above, the SCR-274N were the Command radios, not the
Liaison radios.   Assuming you meant SCR-274N, might you remember if the
hams used Voice or CW for their activities?”

Unfortunately, he responded “Sorry I can not add to your radio question.
The info in the book was obtained from one or more of the PAA-Africa radio
operators - who have all passed. We used their descriptions in the text.”

73 Mark K3MSB

On Fri, Dec 29, 2023 at 2:00 PM MARK DORNEY via ARC5 <arc5 at mailman.qth.net>
wrote:

> The J-37 key is fine for most applications, and the SCR-274-N really
> wasn’t used all too much for CW ( it had the worlds worst cw key built into
> the pilots control box ), but the correct CW key to use in an Army Air
> Corps aircraft is the US Army Signal Corps J-8 “Flameproof” key.  The J-37
> could be used if the J-8 was’t available.
>
> 73
>
> Mark D.
> WW2RDO
>
> “In matters of style, float with the current. In matters of Principle,
> stand like a rock. “.   -   Thomas Jefferson
>
>
> > But Dave...your photo shows a USN Type 26003A key and not a USAAF
> J-37!  :-)  (I like both keys.  The 26003 is also myll favorite straight
> key.)
> >
> > The Wikipedia ARC-5 has photos of all major components of the standard
> two transmitter and three receiver USAAF SCR-274-N and USN AN/ARC-5 (with
> AN/ARR-2) installations.  Those photos are ones that I made of some my sets
> in 2007 to replace the useless photos of ham-hacked junk that were earlier
> in the ARC-5 Wiki article.
> >
> > I assemble these and all other military systems ONLY in their "in
> service" configuration.  Those ARC-5 Wiki photos include:
> >
> > SCR-274-N
> > Receivers BC-453-B, BC-454-B, BC-455-B
> > Transmitters BC-457-A, BC-459-A
> > Controls BC-450-A, BC-451-A
> > Provides two HF command channels plus LF/MF beacon band.
> >
> > AN/ARC-5 (with AN/ARR-2)
> > Receivers R-4A/ARR-2, R-26/ARC-5, R-28/ARC-5
> > Transmitters T-20/ARC-5, T-23/ARC-5
> > Controls C-30A/ARC-5, C-38/ARC-5
> > Provides one HF (fixed) and four VHF (crystal) command channels plus VHF
> ZB homing with six selectable modulating frequencies.
> >
> > It's amazing how much more versatile and useful the above 1944 AN/ARC-5
> was compared to the above 1942 SCR-274-N for similar size and weight.  Few
> hams have ever had any interest in the AN/ARC-5 in its typical "in service"
> configuration.
> >
> > Mike / KK5F
> >
> > -----Original Message-----
> > From: David Stinson <arc5 at ix.netcom.com>
> > Sent: Dec 29, 2023 9:39 AM--
> > (photos)
> >
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