[R-390] CV 157 stuff - VOA traffic

[Sheldon Daitch]

Lester,

One of the interesting aspects of the admin traffic was that when the personnel overseas were coming back to the US, especially official trips, some of the traffic would be related to lodging reservations and credit card numbers would be passed in the clear.  In all the years I worked the Greenville end, and saw the credit card numbers, I never heard of any problems with credit card fraud.

The Greenville transmitters ran the RTTY on one of the sidebands on the TMC transmitters, simple AFSK, Northern Radio tube type tone generators.  We used a high set of tones and low set of tones, keyed with the same information and the Northern Radio tone demodulators had a voting circuit and compared the two sets of tones on the receive end for keying the DC loop.

The Greenville transmitters, the TMCs, were the normal feeder transmitters.   The transmitters at the relay stations, were dedicated lower power HF transmitters normally used only for the RTTY circuits.  In those days, we had a six days a week schedule with Liberia, Kavala, Rhodes, Munich and Tangier and then we added Botswana.   

When I started at Greenville, we had two ASR-28s, one on the receive path and one on the TX path.  All message traffic was on paper tape.  The outgoing traffic from DC had been punched into a master tape to send to the relay stations, done by the prior evening shift supervisor, so the morning tech did not have to deal with individual messages.  On our receive side, we cleaned up the traffic tapes and resent the messages to DC via TTY circuits on the microwave system.

At some point, late 1980s, we replaced the Model 28s with Extel system equipment.  The Extels were neat - no more paper tape - but we ran into one interesting problem with them.  When we weren't running traffic, we ran an idle channel filler and we found the memories in the Extels weren't large enough to hold the message traffic and the idle channel data.  I don't remember exactly what our workaround was - I'll probably have to think about it for a bit.

73
Sheldon


-----Original Message-----
From: Lester Veenstra [mailto:lester at veenstras.com] 
Sent: Friday, February 21, 2014 5:02 PM
To: Sheldon Daitch; 'rbethman'; r-390 at mailman.qth.net
Cc: greenkeys at mailman.qth.net
Subject: RE: [R-390] CV 157 stuff

And these ckts had FDM FSK channels above the program audio, carrying unencrypted admin traffic, from HQ, out to the HF relay sites. 


Lester B Veenstra  MØYCM K1YCM W8YCM