[GreenKeys] Tempest Model 28?

[zeke440 .]

The early attempt at "Low Leveling" the Mod28 ASR was the An/Ugc 13
it had a tube keyer setup in the LESU behind the printer.
I believe the tube was a single "1006".  The radiation pattern of this conf.... was well over 500 feet... even with the +/- keying at 20 mils, mags and gold contacts on the keybd/TD (there was another mod to run the contacts using a light/appature sig generator... maybe another maching also as noisy as the UGC13) 

The last Low Level Mod28 I worked on was the AN/UGC 54B.
 
Now this beastie had the lower cabinet full of real 
LOW LEVEL circuitry.  I forget the specs for the internal keying/kybd signaling but this machine could operate with a radiation pattern of something less than 50 feet.
 
If memory serves me... 
The KSR & RO models were AN/FGC 70 and 74. also with the lower cabinet full of "Low Level" shielded boxes. 
 
You would find inside... a keyer card for each set of magnets... one for each set of contacts... and a card for 
the secure stepper magnets on the kybd and TD 
(ready to wire for stepped secure operation)  
All cabling will be shielded,twisted, with shielded twisted pairs, each pair with its own "drain"
 
While the LESU looks similar to the older mod28 versions
the in/out signaling does not route thru them.
the UGC13 had a polar relay in the LESU but the signal 
keyer ckt was the tubed "module" not the relay.  I guess if you had to hook up to a "non-low level circuit" you would have used the two in series...? never had to so I don't know for sure why the Polar relay was still there... maybe just to fill the empty space on the LESU... as most of the UGC 13s were field modified.  The 54B all signals route thru the YESU inside the cabinet base unit... which needs to be cooled by
a 50/100 cfm "muffin fan" cab door modification.
 
I do have a set of circuit diagrams at my place in OH but wont be back there till later this summer.  Some time ago I did make a few scans for someone here in the list... Hopefully they will catch this and if they still have them
can get the info to you sooner.
 

 Andy  


 
> From: k1lky at earthlink.net
> To: greenkeys at mailman.qth.net
> Date: Thu, 25 Jun 2009 22:45:59 -0400
> Subject: [GreenKeys] Tempest Model 28?
> 
> I see that Tom has made up some little interface boards with an opto 
> isolator to run the ST-8000 (or other low level logic output T/U) with 
> a normal voltage loop supply. I plan to get a couple.
> 
> BUT, I have in storage a Model 28 that I think is set up for low 
> voltage/tempest operation. I have not seen it for some time, but it 
> has extra "stuff" in the pedestal behind the sloped knee panel. No 
> doubt someone has run into these in military service. I presume it 
> would work directly with the Tempest Dovetron or ST-8000.
> 
> What's it called, and where would I get technical info to hook it up?
> 
> Roy
> 
> 
> Roy Morgan
> k1lky at earthlink.net
> 529 Cobb St.
> Groton NY, 13073
> Home: 607-898-3607
> Cell: 301-928-7794
> 
> 
> 
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