[ARC5] Re: [Milsurplus] SCR-274-N Transmitter Dial Accuracy

[John Hutchins]

Michael -
This peice of information should wind up on the Wikipedia!

http://en.wikipedia.org/wiki/ARC-5

Info Michael Tauson wrote:

That collaboration had its own problems where WE
couldn't follow basic instructions.  A.R.C. specified Sylvania &
Raytheon Type 78 tubes due to the interelectrode capacitance.  For the
first 5000 receivers, WE used RCA tubes which did not pass spec (even
though they managed to slide past Navy inspection) due to several
issues, including higher capacitance.  To correct for this, WE
modified the coil assemblies which caused them to no longer work with
other RU receivers.

A.R.C. called a meeting with WE and the Navy about this problem in
1943.  At the time, WE had 150,000 Sylvania 78s on hand so they were
ordered to build the coils sets for the receivers using them according
to the original design and the not get creative anymore.  This also
resulted in a change of the designation for the affected coil sets.

Hutch







> On Sat, Jul 5, 2008 at 3:21 AM, David Stinson <arc5 at ix.netcom.com> wrote:
>
>   
>> You might be surprised how specifications like ".03%" come about.
>>     
>
> Dartboard?  Ouiji board?
>
>   
>> I wouldn't doubt that someone pulled .03% "out of the air,"
>>     
>
> Or somewhere.  :-)
>
>   
>> .03% is silly.
>>     
>
> It's a military spec.  You'd expect otherwise?
>
>   
>> As an aside:  This wasn't the first collaboration between A.R.C.
>> and Western Electric.  They had a similar deal  that covered the last of the
>> GF/RU sets.  Correct me if I'm wrong,  Michael:
>>     
>
> Nope, you're right.  That collaboration had its own problems where WE
> couldn't follow basic instructions.  A.R.C. specified Sylvania &
> Raytheon Type 78 tubes due to the interelectrode capacitance.  For the
> first 5000 receivers, WE used RCA tubes which did not pass spec (even
> though they managed to slide past Navy inspection) due to several
> issues, including higher capacitance.  To correct for this, WE
> modified the coil assemblies which caused them to no longer work with
> other RU receivers.
>
> A.R.C. called a meeting with WE and the Navy about this problem in
> 1943.  At the time, WE had 150,000 Sylvania 78s on hand so they were
> ordered to build the coils sets for the receivers using them according
> to the original design and the not get creative anymore.  This also
> resulted in a change of the designation for the affected coil sets.
>
>   
>> From the 1920s through the war, while A.R.C. did all the
>> design and engineering,  they actually built at their factory
>> only small lots
>>     
>
> Initially, RFL designed, Stromberg-Carlson built and A.R.C. installed
> and serviced.  That changed quickly with A.R.C. doing the design &
> test work plus ever increasing levels of production.  All of the
> A.R.C. tagged equipment was built at their facility.  In 1934, RFL was
> effectively removed from the picture and A.R.C. wound up on top of the
> stack.  (1934 was a very magical year for A.R.C..)  After then, S-C
> was a contractor, to be sure, but building separately labeled
> equipment.
>
> The RAJ, RAT, and RAV were, in fact, short run systems.  But the
> ARA/ATA was built by both S-C and A.R.C. with the appropriate
> contractor codes.  Also, wasn't there an order previous to 1470-NY-41
> that went to A.R.C. instead of WE?
>
>   
>> inital "spec" runs like the first sets of 1470-NY-41
>>     
>
> These were built by WE using WE components, including the faulty
> variable capacitors.
>
>   
>> and accessories like shock mounts and control boxes,
>>     
>
> A lot of the control boxes at least were farmed to minor manufacturers
> and their names appear on the ID tags.  If you think about it a bit,
> aside from subcontracting - which everyone did - relabeling doesn't
> make a lot of sense
>
>   
>> Stromberg actually built almost all the "RU" receivers branded for A.R.C.
>>     
>
> I might want some evidence of this.  S-C certainly built much of the
> very early RFL/A.R.C. equipment, which was actually branded as RFL
> equipment and this may have been true of the Model B based sets, but
> A.R.C.'s production capability had already started growing.
>
>   
>> I don't know if A.R.C. built the A.R.C.-branded AN/ARC-5 sets, but it wasn't
>> Stromberg;  S.C. sets have obvious differences.
>>     
>
> Yep, it was A.R.C..  That same production capability was converted to
> manufacturing the Type 12 et al even after postwar cutbacks.  The
> excess capacity gave them room to pursue the ARC-39, APR-9, and
> various sonar and other projects.  By the time Cessna bought A.R.C.,
> there were four additional transmitters (T-20 through -23); the R-20;
> the T-25, R-31, R-33, and R-38 (or -39 - can't remember right off)
> which all fit a 1/4 ARINC rack (called the Series 40 rack and came in
> one through four bay versions); the Type 210 (RT-11); and two
> different autopilots on top of the R-11, R-19, T-11B, T-13A, TV-10
> (CV-431), Type 15F and Type 21A.  There may have been one or two other
> peices but those are the biggies.
>
> It's not unusual to underestimate the production capabilities at
> Boonton at the beginning of the war, let alone at the end.  They did a
> lot with a little then kept growing from there.
>
> BEst regards,
>
> Michael, WH7HG
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