(U) [R-390] Interesting Link Vietnam NSA released report

[Les Locklear]

>From The Hammarlund Historian SP-600 link: 
http://www.hammarlund.info/sp600.html

 The only SP-600's not included on this list that I'm aware of are the 
"hybrid" SP-600's manufactured during the Vietnam war. The military 
designation was R-1511/GR. These models used only 9 tubes, dual voltage 
regulators, 8 printed circuit boards and a 200 khz bandpass filter. usually 
used in banks of 5 receivers and connected to video recorders. They were 
used for signal intercept work in the hf spectrum to detect where the enemy 
was talking. The reels of tape were sent to the NSA in Ft. Meade, Maryland 
for interpetation. (We have a manual for this unit on the "manuals" page.)
----- Original Message ----- 
From: "mikea" <mikea at mikea.ath.cx>
To: <r-390 at mailman.qth.net>
Sent: Monday, February 25, 2008 2:58 PM
Subject: Re: (U) [R-390] Interesting Link Vietnam NSA released report


> On Mon, Feb 25, 2008 at 03:49:19PM -0500, DJED1 at aol.com wrote:
>> I found it a fascinating read.  Apparently much of the North  Vietnamese
>> communication was encrypted CW, accounting for the large numbers of 
>> R-390s and
>> intercept operators needed in that time period. Today it seems  strange 
>> to read
>> about all the manual effort required to encode, intercept,  decrypt and
>> disseminate the information.  But it was 40 years ago  (ouch!-seems just 
>> like
>> yesterday). I did see a mention of R-392s being used  for mobile 
>> intercept stations.
>>
>> Strange that some classified paragraphs were released, while others are 
>> gone
>> altogether.
>
> (U) Not so strange: not all information cools at the same rate, and
> things that might reveal current (or not yet sufficiently aged) methods
> and sources [SEVENTEEN WORDS REDACTED]
>
> (U) I'm quite interested in the NV cryptosystems, myself, but I don't
> expect to see anything about them this century. Anyone here got stuff
> that can be shared?
>
> (U) Lots of R-390s on the ground and in the air, lots of R-392s and
> other gear on the road, and at least some RACAL 6217 gear mounted on
> helos and being used to DF sources. Wouldn't surprise me if there had
> been RA-17 gear in use, as well as the SP-600s, HRO-50s, Collins, and
> whatnot.
>
> -- 
> Mike Andrews, W5EGO
> mikea at mikea.ath.cx
> Tired old sysadmin
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