> >
> If the TX audio were digitized and then delayed, it would be possible
> for the VOX to turn on the transmitter after the beginning of a word,
> and still send the whole (delayed) word. It really could be the QSK of SSB.
Somewhere in the dim past, such a device appeared in a QST
article sometime in the 80's(?), with circuit boards available from
A&A engineering. I think it was called SmartVox or something like
that. I actually built and have one (somewhere ... buried under piles
of other long forgotten projects that didn't quite live up to
expectation).
Problem with it was that the audio quality out of the thing (at least
mine) was not particularly good, so I never used it. Plus there was a
low level ground loop variety hum that wouldn't go away on my then
IC-745 no matter what grounds I tied to what. A&A no longer lists it
on their website.
It used a bucket brigade device for voice delay, and keyed the
transmitter (through PTT) triggered from undelayed audio. So the
transmitter was keyed up before the delayed voice got there. It then
stayed keyed until the bucket brigade emptied out. It was VERY
effective, actually, in completely eliminating clipping issues with
VOX. That aspect of it worked well.
Seems it would be relatively simple to do the same thing with
modern parts and with clean audio out. Or perhaps the original
dsign could be cleaned up to reduce/eliminate the audio distortion (it
sounded to me like something in the audio path was clipping).
Grant/NQ5T
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|