[GreenKeys] Fwd: The Flying White House 1947

[WA5CAB at cs.com]

Duncan,

The exciter part of AN/TRA-7 is O-39/TRA-7.

CV-31/TRA-7 is nearly two-thirds the size of a BC-610, with proportionant 
weight.  I have one.  Can't lift it by myself.  Maybe they used the upper 
panel and powered the thing off of several dynamotors.



In a message dated 02/18/2012 21:03:47 PM Central Standard Time, 
duncanancy at earthlink.net writes: 
> I just received the original photo from Don - it is going to the AWA 
> Museum.  Looking at the photo with a magnifying glass, I can see a 
> little more detail than was available on the scans.
> 
> The unit behind the operator's head is definitely a diversity FSK 
> receiving converter.  I can make out the meter switch markings and they 
> are things like "Chann B"; "Chann A + B"; "Polar"; "Neutral"; etc.  I 
> was then able to identify the converter as of the FRF &CV-31/TRA-7 
> family (although a slightly different configuration).
> 
> Below the CV-31 is a BC-348 receiver (must have been another one unless 
> they were using one of the ARC-5 receivers for diversity).
> 
> Below the BC-348, I can just make out another chassis with a large shiny 
> dial.  This might be the FSK modulator - something like the O-79/TRA-7 
> used (along with the CV-31) in the AN/MRC-2 in this time period (and 
> later in the early AN/GRC-26s).  So maybe the ART-13 was running true 
> FSK (but where is the other coax - on the other side of the ART-13?)
> 
> In looking up the O-79, I came across an interesting document: "Military 
> Teletypewriter Systems of World War II" at  
> http://www.nonstopsystems.com/radio/article-AIEE-1948.pdf
> (I was surprised to learn that there was some Multi-Channel, Independent 
> Sideband, radio teletype used on high volume circuits during WWII and 
> that the Bell system had been using it prior to WWII.)
> 
> On the front of the SIGNIN, between the keyboard and paper tape reel is 
> something that looks like a perforated tape reader.  So there must have 
> been an "Iron Horse"/GPE perforator somewhere.
> 

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