[ARC5] BC-454-B listed in THAT place.

[WA5CAB at cs.com]

Basically the Interphone system installed in the aircraft or vehicle.  
Which determined whether the crew had had to have Hi-Z or Lo-Z headsets.  AFAIK, 
replacement aircraft from about late 1942 or early 1943 on came with Lo-Z.  
So the completion of the changeover was sorta dependant on survival rates.  
:-)  

MC-385-(*) Impedance Adapter allowed using newer Lo-Z headsets HS-33 and 
HS-38 (HS-30 could be configured either way) with older Hi-Z systems.  I don't 
know of an adapter being made for the reverse case.  

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

In a message dated 08/15/2016 10:49:13 AM Central Daylight Time, 
ac2eu at yahoo.com writes: 
> OK on the taps, but what determined if the lo-z was used or not?. I have 
> "B" models that have the taps but are wired for hi-z.
> 
> 
> 
> 
> On Monday, August 15, 2016 11:39 AM, WA5CAB--- via ARC5 <
> arc5 at mailman.qth.net> wrote:
> 
> 
> 
> No. The "-B" models (or most of them) were made by Western Electric.  The 
> first few thousand were still painted black wrinkle but the majority were 
> unpainted.  The "-B" models also have the 250 ohm (Lo-Z) tap on the receiver 
> audio output transformer and two of the transformers in the modulator.  
> Which isn't visible from the outside.  Note 3 on the transmitter system 
> schematic in later T.O. 08-10-50 says 600 ohms but Signal Corps practice at the 
> time was to call it 250.  Nameplates on the receivers and transmitters were 
> also moved to the right side of the chassis on the unpainted ones.  Which 
> made sense for several reasons.
> 
> 
> 
> 
> 
> 
> 
> 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/arc5/attachments/20160815/cc6d6750/attachment.html>