[ARC5] SCR-274N VHF Resurrection (long)

[David Stinson]

----- Original Message ----- 
From: "Mike Morrow" <kk5f at earthlink.net>

> What did you wind up using as the basis for your BC-942 receiver?
> Were you able to get anything useful from that junker R-28 we traded
> a few years ago that was missing some of the gears in its O-101
> tuner, but appeared to have once been a BC-942?

That's the one you see in the photo :).  It has every hallmark of
a re-nomenclatured  BC-942 and none of the "tells" for a later
production R-28.  I believe  it to be the correct receiver.

> The easy "conversion" (compared to the BC-950 transmitter) of the
> BC-942 receiver to the R-28/ARC-5 by changing nomenclature tags
> must have eliminated the chance of any surviving with the original
> BC-942 plate.

I think that very likely.  I've been collecting these items for
better than 40 years.  I've never seen a BC-942, nor do I know
of anyone who has.  If anyone has such a beastie, please share
some photos with us.

> Without implying any disagreement, I'm interested in the basis for
> stating superior performance.  Superior adaptability to an existing
> US (but not UK) set is obvious, yes...but superior performance?

Techs of the era report lots of problems keeping the SCR-522
in adjustment, as well as mechanical problems with the
channel-changing contraption.  Dynamotor problems, production
foul-ups, quality-control problems and the lack of trained installers
and repair techs/spares delayed and nearly derailed SCR-522
all down the line.  Witness how rapidly the 522 was dumped in
the post-war Air Force in favor of AN/ARC-3, while the late
AN/ARC-5 version of this set stayed in service with the Navy
for some time.  It's been reported by one of our members
(though I haven't tried to look it up myself)  that the Bell X-1,
which was the first aircraft to officialy break the sound barrier
on 14 October 1947, carried the AN/ARC-5 VHF set.
And I admit- A big dose of person bias went into my point;
Mia Culpa ;-).

> It looks like hams will be hearing your BC-950 on 146.52 (and 116.1) 
> MHz AM.
I forgot to mention this:  Of the original transmitter crystals 
installed,
only the 116.1 MC works.  The others are dead; probably from bakelite
outgassing deposits, which happens to old crystal alot.  I'll clean 
the later.
Can't find where I wrote the original freqs down, but they were not
those listed in the ARC-5 manual.

> A problem...your BC-456 should be a later aluminum-finish -B/E 
> model!  :-)
Wellll.... True enough.  I have an "E" model and when I set it up
for VHF, I shoudl probably use that one.

> But seriously, the next thing you could add to your installation is 
> a BCB
> BC-946-B in place of the BC-453-B, and a R-1/ARR-1 feeding it for a 
> USAAF
> version of the ZB homing system.  I'm pretty sure that such 
> installations
> did NOT use the ZB antenna switch or control box, so only the R-1 
> and the
> BC-946 (fed only by the R-1) would be needed, plus a hard-to-find 
> MC-415
> BCB dial on the BC-944 control box.

Ack!  As Jerry Clower would say: "You done flung a cravin' on me!"

> After that, if you wanted to really go overboard and didn't mind the
> anachronism, you could add the BC-608 and BC-616 "Pipsqueak" 
> components.

Just not *that* big a cravin' ;-)

73 DE Dave AB5S