[ARC5] SCR-183 / SCR-283 Info

[WA5CAB at cs.com]

Outstanding writeup, Dave.  I just put it into my Reference Data folder.

Although the main subject of this thread was or became SCR-183/283, the 
original post asked about GF and by extension RU.  Among other differences 
between (and here I've got to weasel-word and say "later" as the earliest GF/RU 
and RU manuals I have are GF-3/RU-4A and RU-5) the later Navy sets and the 
AAF ones is that all of the Navy radios have their filaments wired for 14 
volts.  Regardless of what it may say on the nameplate.  The 28 volt junction 
boxes have dropping resistors.  And not all of the receivers are 
interchangable.  The receivers built on the receiver-only contracts which are at least 
RU-5, 11/12 and 18/19 are different from the ones built on the combined (with 
GF) contracts.  For example, if you plug an RU-17 receiver into an RU-19 
Junction Box, it will be dead because the AGC amp tube cathode will be 
floating.  There are other differences that I haven't traced out, so I can't 
currently say whether you can do any damage by such mixing.  The Radio Set and the 
Receiving Set dynamotors are also wired differently and are not 
interchangable.  Navy Type Numbers are different, of course, for both the receiver and 
the dynamotor variants.

In a message dated 8/28/2010 11:26:20 PM Central Daylight Time, 
arc5 at ix.netcom.com writes: 
> he SCR-183 (12 volt, BC-230 transmitter) and
> SCR-283  (28 volt, BC-430 transmitter) don't get nearly the
> respect and interest they deserve.   They saw service from 1932 
> until well after WWII, and longer service than that in smaller-
> nation air forces.  They are an excellent design
> * for the mission for which they were intended. *
> They got some bad press because they got deployed 
> inappropriately in some high-profile cases.
> They are lower-power than the SCR-274N and ARC-5
> and were less available in the surplus market, so most
> of them have gone to grief by now.  
> That's too bad, because it's a cool set.  
> 
> The Army and Navy sets were identical, at first.
> The design originated with Aircraft Radio Corporation
> in 1932 with the Navy "GF" (at the time, GF was the 
> designation for the complete set including receiver.  
> "RU" was the receiver alone.  
> The designation changed to "GF" being just
> the transmitter with the next itteration, GF-1).
> 
> The Army copied the 1932 design nut-for-bolt under 
> Order Number SC. 132311, June 1932
> and designated it SCR-AA-183.  
> That's right, folks: SCR-274N was not 
> the first time the Signal Corps copied 
> a design A.R.C. had done for the Navy. 
> This early design suffered from problems with the
> plug-in tuning unit coil tapping mechanism, 
> and with tube quality issues.
> In 1934, the Navy had A.R.C. completely overhaul
> the design of the GF transmitter and produce the 
> GF-2, which is the higher-power P-P 837 transmitter 
> with which we are familiar.
> The Army, having far less money to throw around
> (they don't call it "spending like a drunken sailor"
> for nothing),  incorporated the mostly mechanical
> improvements between GF and GF-1, 
> built some false-starts like transmitter BC-AA-200,
> but eventually nudged the design to June 1935's SCR-AE-183
> and the set stayed basicly the same until the last production runs
> (-AR and -AS) in the first year of the war.
> 
> Things get very muddy between -AA and -AF.
> A.R.C. made the 1932 -AA, based on the GF,
> then handed it off to Western Electric and Graybar
> in 1934, which then became the -AB.  Weco built 
> the -AD in June of 1934 and the -AF in July of 1935, 
> and all were basically the 1932 design from the old GF, 
> bad coil tap contacts and all.
> In the middle of this, in June of 1935, A.R.C. produced the
> mechanically improved -AE model, which went on- with
> minor differences- to be  the standard design 
> to the end of production.  
> But that's all another (long) story.
> 
> Mike Hanz has been exceedingly kind and generous 
> with time and help on the SCR-283 set I'm building.
> Here's an "intermediate" stage:
> 
> http://home.netcom.com/~arc5/SCR-AH-183/183a.JPG
> 
> and the latest improvements:
> 
> http://home.netcom.com/~arc5/SCR-AH-183/183STEEL.JPG
> 
> The dynamotor is a later, unpainted version.
> I'm considering remounting and compacting the set.
> 
> On to your transmitter.  
> You'll need a proper tuning unit.  Please send a photo
> of the nomenclature plate of the unit you have, since 
> there's just a chance it's an early one that will work.
> Here is the diagram and notes for connecting your transmitter.
> Your BC-430 is the 24-volt version, and only the 
> tube fil wiring will be different: 
> 
> http://home.netcom.com/~arc5/SCR-AH-183/BC230TX.JPG
> 
> Parts lists are at:
> 
> http://home.netcom.com/~arc5/SCR-AH-183/230PAR1.JPG
> 
> and
> 
> http://home.netcom.com/~arc5/SCR-AH-183/230PAR2.JPG
> 
> Tubes:  The original tubes have become little golden gods to 
> the audiophools, but don't give up.  Many tubes will work 
> fine in this circuit.  I've wired 6AQ5s as triodes (screen to plate)
> and mounted them in old four-pin sockets.  They neutralize and
> tune-up just like the expensive tubes.  The set will put out a
> mighty 3-4 watts carrier.  Don't laugh; I've been working 
> 100-200 mile AM contacts on our local nets with it.
> With proper tuning and a good power supply, the rig is surprisingly
> stable though, as with any MOPA rig, there will be a certain
> amount of "chirp" on CW.  Not bad on mine.
> 
> If you're interested in going further, I can give you a lot more info.
> 
> Right now, gotta get the kids to bed. :)
> 
> 73 OM DE Dave AB5S
> 
> p.s. Here's another project that's proceeding apace 
> with Mike's kind help:  My Navy ATB / ARB, 
> which is on the air making contacts:
> 
> http://home.netcom.com/~arc5/ATBARB.JPG
> 

Robert & Susan Downs - Houston
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