[Milsurplus] Chicken or Egg Question

[WA5CAB at cs.com]

Zenith developed the BC-221 (ref an entry in one of the Green Books, 
although they may have had subcontractors as I have a pre-production prototype 
labeled BC-221-T1 that was made by Premier Crystal Labs, Inc.).  The large 
number (27 not counting the T1) of suffix letters reflects Signal Corps policy 
of usually incrementing the letter for either modifications or different 
contractor.  I don't have the contractor list handy and can't accurately recall 
all of them, but there were several.  Each contractors models were slightly 
different.  Plus as time went on, improvements in the art were incorporated. 
 Early models have some 30's glass tubes.  One model uses Loctal's.  Etc.  
The BC-221 was produced over a period of about ten years.

In a message dated 12/8/2010 2:03:15 PM Central Standard Time, 
pete at petelancashire.com writes: 
> I'll toss in another question .. why so many variations of the BC-221 ?
> 
> Jack .. how about a scan of the page ?
> 
> -pete
> 
> On Wed, Dec 8, 2010 at 9:23 AM, Jack Antonio <scr287 at att.net> wrote:
> >It is frustrating trying to clean and  organize the shack, I keep
> >getting distracted.
> >
> >Current distraction is that I found a Bendix Aviation Radio Catalog,
> >copyrighted 1941.
> >
> >In it is an IF-12 Portable Frequency Indicator, which looks exactly like
> >a BC-221.
> >
> >So the question is, which came first? Did the military adopt the civilian
> >component, or did Bendix market commercially something developed
> >for the military?
> >
> >Also found a listing for an RA-12 Instrument Landing Receiver, and
> >its companion ground transmitter, the TG-12  Looks
> >like a midway step between the Navy's ZA system, and the Army's later
> >RC-103 and AN/ARN-5.  Used one 93.3 Mc transmitter for both localizer
> >and glide slope.
> >This is going to take some more research. (Another distraction).
> >
> >Jack Antonio WA7DIA/4
> >
> 

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480