[ARC5] Some ARC Type D History and Development

[David Stinson]

Thanks for this, Mike.  Great stuff.
Don't forget the unaccountable throw-back
of the W.E. SCR-AF-183 clone of GF-1.
We'll probably never know the "why" of that one.

On the GF/RU meters- I've never seen one that showed
evidence of having been mounted anywhere.
All: If you have WWII aircraft gear that is marked
with a yellow circle enclosing "RT(number)", that piece was
actually installed by a "Radio Technician" in a Navy aircraft
or other Navy installation.  There are variations on this
"install tech"  marking, but this is the only one
I can currently document.
While I have several pieces with "tech" marks, I've never seen
a GF/RU meter with any such mark, or with "air station refurb"
marks, which would indicate it was in service somewhere.
Anyone seen such a meter?

> The more I've studied what information I have on the A.R.C.
>Type D descendants, the more respect I have...

Indeed.  When run as-designed with the correct dynamotor,
the correct covers in place etc.,
the system is surprisingly stable and sounds excellent on-the-air.
A.R.C. must have been using their special "stabilizing" metal alloy
for their variable caps a lot earlier than 247N.
One of these days I'm going to put a service monitor on it and
do an "official" drift measurement.   After a half-hour warm-up,
I no longer need to check the transmit freq; it will be "on."
If you're going to use it on phone, it really does need a bit of
an amp; 3-4 watts is kinda tough on 75 meters unless the band
is empty and quiet.  And the simple regenning between the
antenna jack and the third RF stage will bring the weaker
stations up out of the noise.


> One has to wonder why, somewhere around 1935,
> the USAAC and ARC didn't consolidate all designs and settle
> on the more capable USN version that
> existed by late 1934.  I doubt that there would have been gross
> cost differences, especially once everything was being made
> the same and parts supply was simplified.

I'd bet Gordon has some insight on this.  To make such a change,
A.R.C. would have been able to argue for "retooling"
and other costs.  And then there's the "human" factor.

The Chief Signal Officers of that time:

Maj. Gen. Irving J. Carr (1931 to 1934.
                        Had no budget- Sig Corps <3000 officers and 
men)
Maj. Gen. James B. Allison  1935-1937 ("caretaker")
Maj. Gen. Joseph O. Mauborgne  1937-1941 (focused on Radar)

had little money and no incentive to make expensive changes
in systems that were perceived as "good enough."

Time has caught up to me- off to work!
73 Dave S.