[GreenKeys] Re: Dovetrons!

[Robert McConnell]

At 1/24/03 05:44 AM -0800, kr4wm wrote:
>The comparison article between the ST-8000 vs Dovetron
>didn't show up here either.
>
>For what it's worth (please don't kill me!) A fellow
>gave me the hookup info for the Dovetron Tempest to
>PC awhile back on the list. I still haven't tried it
>yet, been too busy with work, but since I retired as
>of YESTERDAY (YIPPIEEEEE!!!!) I have plenty of time
>on my hands to play with the Tempest now. One thing
>to be aware of with the Tempest- it doesn't have the
>"standard" RS-232 out the back- it has BNC jacks for
>each function. I remember something about military-grade
>RF shielding being the main difference between an
>"ordinary" Dovetron and the Tempest model.
>
>73, -Web Williams in Myrtle Beach, SC

The Tempest specifications were developed after it was discovered that 
anyone with a little knowledge and some relatively inexpensive equipment 
could copy the RFI generated by a 60mA teletype loop from several hundred 
feet away. Since most military teletypes were on classified circuits, that 
was not considered good security. The Tempest requirement was that the 
signal could not be detected by a test set one meter away from the open 
cabinet of a M28 set. Unfortunately, many comm centers had both Tempest and 
60mA loops in close proximity, so we ended up replacing a lot of low level 
polar relays that had their contacts welded together when plugged into the 
high voltage loops.

Bob McConnell
ex-RM2, TTY repair: NFIT - USS Cochrane (DDG-21),
          NLM - NAVCOMMSTA Honolulu
N2SPP