[GreenKeys] Dovetrons

[wa2hwj@att.net]

I am glad that there's a lot of takers for the Dovetrons. I am not in the 
posiition to bid on the lot, but maybe George's contact can do that. I have 
seen (and bought) Tempest Dovetrons for $20 to $50. As far as "how do they 
look and do they work?", well that's the crap shoot with buying from Uncle 
Sam. I have had probably a dozen or so Dovetrons, of every type, and have 
rarely found one to be inoperative. They were very well built units. The 
Tempest units can be made to receive and print to a HV loop with the simple 
circuit on www.rtty.com. To modify them to transmit from the loop is pretty 
easy. The MIL188 interface is similar to RS232, but the mark and space 
polarities are reversed and the volatges are +/- 6VDC, not 12VDC. Most of the 
Tempest sets I have seen do have the regenerator, but you have to select the 
output speed (to the TTY) with a DIP switch inside the machine. Then you have 
a front panel switch to select the input speeds. The full-blown "commercial" 
Dovetron has selectabel input and out speeds and a FIFO buffer (grabbed one of 
them many years ago...paid over $300 for it at the time).

Jack WA2HWJ
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