[ARC5] ARC-5/SCR-274 Navagation Receivers?
David Stinson
arc5 at ix.netcom.com
Sat Apr 30 00:21:40 EDT 2011
I just got in from 280 miles round trip to repair a signal bungalow
for the railroad, and the call came after a full work day was already
done,
so I haven't had a chance to read everything in this interesting
thread.
But I will interject a couple of things before collapsing into bed.
We've covered how ADF and RDF are different animals and
ADF isn't an issue, right?
First- remember that WWII was a global conflict, with many often
conflicting operational environments. Don't fall into the common trap
of thinking of our sets within Amero- or Euro-centric limits.
While "radio range" transmitters were set up in most major U.S.
cities, that didn't help you with the very many more airports
into which you might need to fly which had no A-N "range" transmitter.
Most of the world had no such "range" system in place,
and it wasn't good for everywhere in the U.S., either.
If you wanted to fly into "IchyArmpit Naval Air Station, Idaho,"
you'd "fly the beam" of the radio ranges until you got to Boise,
then switch to one method or other of RDF to direct you
to the Itchy Station NDB. The Navy kept RDF capability
because they might be flying into a strip on a barrier island
of the coast of Brazil, which had only an old 50-watt 278 KC
voice transmitter that doubled as an NDB and a desk lamp
for a tower light.
To understand why the Army dropped the loop connections
after moving beyond the SCR-183, remember how the Army
was in puppy-dog, roll-over-n-wag-your-tale love with
everything British. The Brits didn't let fighter aircraft RDF
their way home; they did it the other way-round.
The Brits RDFed the aircraft from the ground with direction finders,
and that's what the USAAC went about trying to do.
The documents are full of pilots asking some tower to "get a fix"
on their position. While the BC-453 was still needed for
"flying the beam" from sector to sector and for talking to
towers on Longwave (usually 278 KC), if a couple of P-47s
got lost in the rain they were likely to call the nearest Army Airways
on 4 MC and ask them to "get a fix" on them to bring them in.
The idea of cribbing the Navy's ZM system using the BC-946
and an AN/ARR-1 was a late-comer. Given the condition of
most BC-946s and ZMs when they hit the surplus market,
I don't think that system got installed very widely in the Army's
aircraft. I think that system was obsoleted by the AN/ARR-2
before it was ever uncrated, throwing the USAAC into a
state of "confused neutrality" about RDFing from single-seat
aircraft and falling back on their existing "RDF from the ground"
system. It certainly worked, and they didn't have the money
that was showered on the swabbies for "fiddling around."
As for the R-24 not seeing use- I'd disagree.
I don't think a lot of them saw use, but they'd have a role.
Many of the second-tier and tertiary allies in places
like South America and Africa were still equipped
according to the 1920s Naval agreements and would have
used this band both for communication and for RDF with
shore-base broadcast stations. You weren't going to find
an A-N range or a "YG" transmitter in Columbia in 1943,
but you could find "Radio los Mosquitos" on 712 KC to
"home on." You could also talk to a Columbian Navy unit on
600 KC, which would then clamp his key so you could find
him and the possible U-Boat contact he was telling you about.
I'm falling asleep here. More later.
Night, Ya'll.
73 Dave S.
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