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 Post subject: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Thu 12, 2017 1:29 am 
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Wondering if anyone knows what this is?

Maybe part of a WWII triple diversity receiver rack?


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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Thu 12, 2017 8:18 pm 
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Joined: Jan Mon 28, 2013 9:35 pm
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Location: Santa Rosa, CA
You have a very basic diversity combiner. It appears to ba a non-AFC
audio type. Don't recognize the model or what it was a part of.
Steve


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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Fri 13, 2017 12:20 am 
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Thanks Steve. Actually, I don't have it but it's been offered and I wondered what kind of equipment it went with.

I've searched the internet and haven't had any luck which seems odd as it seems like information on even the most obscure equipment can usually be found.

Any idea what the "COS" on the tag stands for? Is is a manufacturer designation?

-Tony


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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Fri 13, 2017 2:19 am 
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Location: Santa Rosa, CA
ton10291 wrote:
Thanks Steve. Actually, I don't have it but it's been offered and I wondered what kind of equipment it went with.

I've searched the internet and haven't had any luck which seems odd as it seems like information on even the most obscure equipment can usually be found.

Any idea what the "COS" on the tag stands for? Is is a manufacturer designation?

-Tony


No idea what 'COS' means but maybe someone else here does.
A receiver diversity combiner takes the audio (or IF) output of 2 or 3 receivers
which are all tuned to the same frequency but on different and usually
widely spaced antennas, and selects which one has the strongest
signal. The idea is to eliminate or at least reduce fading at HF freqs.
These are usually used with RTTY equipment. If you have three
identical HF receivers and room for multiple antennas, its a cool
thing to have. I've had a lot of luck using two antennas in a dual
diversity system using a diple for one and a trapped vertical
for the other receiver. Commercial and military sites used
antennas spaced many wavelengths apart.

One diversity combiner I have here actually breaks down the audio
output of each receiver into 3 overlapping audio bands and 'votes'
on which band of which receiver is used!
Hope this helps.
Steve


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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Fri 13, 2017 3:42 am 
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Joined: Nov Sun 04, 2007 6:01 am
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Location: Redding, CA
I believe that "COS" does refer to a specific contractor but it was not a well known one and I have not been able to identify the contractor. The equipment for which you posted photos appears to accommodate three receivers using an operator (person) as the discriminator. The operator would switch to the receiver showing the strongest signal on the meters above. Very primitive and technically obsolete by 1944 when the contract was issued.
My guess is that not many were made and fewer have survived.

Norman

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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Fri 13, 2017 5:38 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 2948
Location: Seattle WA US
Navy contractor code COS was for Simplex Wire and Cable Co. I don't know if the Army Signal Corps used the same codes.
-Chuck


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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Fri 13, 2017 2:55 pm 
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Joined: Jan Mon 28, 2013 9:35 pm
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Location: Santa Rosa, CA
Thinking about this a bit more, the only tripple diversity system I have
heard of used three SP-400's (BC-779's ?) in a rack. This is a WWII
era set. That seems to be the same era as the combiner you are
looking at. I do have some info and a pic but its buried and dealing
with other stuff now.

As far as value goes, its rare but not really practical these days.
I'd pay maybe $100 just because its so unique.
Steve


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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Fri 13, 2017 3:21 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1135
Location: forked river , n.j. , usa
lots of info here about military sets http://radionerds.com/index.php/Main_Page


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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Fri 13, 2017 4:24 pm 
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Joined: Oct Fri 02, 2009 2:41 am
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Location: Chapel Hill NC
FWIW, I have info on a number of US Navy dual and triple diversity systems here
http://www.navy-radio.com/rcvr-div.htm

But nothing on this Signal Corps gear, sorry.

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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Fri 13, 2017 7:39 pm 
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Thanks everyone for the information.

Norman's observation that it was "primitive and technically obsolete" by the contract date probably explains the condition. From the picture it appears unused.

I'll have a look at it tomorrow and if it's complete, reasonably priced and of a manageable weight I'll probably end up dragging it home.

Thanks again to everyone for all of the information.

-Tony


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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Sun 15, 2017 9:26 pm 
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I did check my WW II magazine which has a picture of 3 BC779s in a diversity setup, but the combiner in the picture is not the same as what is posted here.

Ed W2EMN


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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Mon 16, 2017 2:15 am 
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Location: Santa Rosa, CA
djed wrote:
I did check my WW II magazine which has a picture of 3 BC779s in a diversity setup, but the combiner in the picture is not the same as what is posted here.

Ed W2EMN

Thanks for looking that up Ed. Tony, if you ended up with this
fine old boatanchor (aren't they all?!) could you post a rear
view of the chassis? Very curious about this one.
Steve


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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Tue 17, 2017 2:35 pm 
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zarco wrote:
djed wrote:
I did check my WW II magazine which has a picture of 3 BC779s in a diversity setup, but the combiner in the picture is not the same as what is posted here.

Ed W2EMN

Thanks for looking that up Ed. Tony, if you ended up with this
fine old boatanchor (aren't they all?!) could you post a rear
view of the chassis? Very curious about this one.
Steve


I did end up getting it and here are a few pictures of the back.

It appears to be unmodified and unused. I love the quality of construction of military equipment.


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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Tue 17, 2017 3:48 pm 
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Location: Redding, CA
Very nice! It looks more like an mixer than a diversity comparator. It would be nice if a manual describing unit operation can be found.

Norman

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"No home is complete without music" - Capehart Sound Amplifying and Distributing Systems


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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Tue 17, 2017 7:19 pm 
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Braithwaite wrote:
Very nice! It looks more like an mixer than a diversity comparator. It would be nice if a manual describing unit operation can be found.

Norman


Thanks Norman.

I've been poking around online for a manual and found the following description for TM 11-2515 Diversity Receiving Combining Equipment September 27, 1944:

"If this piece of gear had any nomenclature assigned, then the manual doesn't bother to mention it. This was some large, rack-panel unit with metering and a heterodyne oscillator designed to combine up to 3 receivers (I think) in a diversity configuration."

Now to find a cheap copy or better yet a free download.

-Tony


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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Tue 17, 2017 9:38 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1135
Location: forked river , n.j. , usa
thats the correct tm for your equip. its stand alone equipment.doesn't matter what receivers
were used as long as the audio out was 600 ohm line.

telegraph only , no voice.


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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Tue 17, 2017 11:06 pm 
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http://www.military-info.com/MPHOTO/Man ... /Tmwar.htm

TM 11-2515 Diversity Receiving Combining Equipment (27 September 1944); 32 pages, 12 illus. Price 6.00 {Item No.7572}

The price of two mocha coffee lattes... :lol:

I can afford that... :D

I have the CV series of diversity units with the SP600's. It is all apart at the moment...

You might get all the help you can handle by joining GREENKEYS:

http://www.qth.net/mailman/listinfo/greenkeysm

I have had other diversity combiner units here, but decided that for the use they would get and the rack space consumed, I moved them on.

To really make them sing requires acreage for antennas and good either boatanchor or modern receivers. Then again, computer software would do it all too.

Equipment like this is disappearing fast. Often, it is broken up for parts.

Be careful of that neon lamp voltage reference, very hard and $$$ to replace...

GL

Chas

WA1JFD RTTY since 1971

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There Are None So Blind As Those Who Will Not See: John Heywood, 1546


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 Post subject: Re: Signal Corps Diversity Receiving Equipment
PostPosted: Oct Wed 18, 2017 2:16 am 
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Thanks Chas!

I'm not sure what a "mocha coffee latte" is or how much it costs but I've printed the order form and it goes out tomorrow.


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