[TRLog] PTT on SSB

[Tree N6TR]

N4ZR and I were talking about having TR (oops) control the PTT when using
a DVK or DVP.  At first, it didn't make sense to me, but this might be of
interest to some.  Pete was trying to eliminate some ground loops to 
reduce hum.

> One possibility would be to use the PTT relay in the DVP to tell a port
> what's going on (as your footswitch input now does).  Then the sequence
> would be:
> 
> Receive function key input
> Assert PTT
> Delay
> Tell DVP to start talking, and which message
> Check for open circuit on DVP PTT line 
> when PTT line opens, de-assert TR's PTT
> 
> Maybe this is more hassle than it's worth, but it would seem as if there
> are lines to spare on an LPT port.
>
> What do you think?  Avoidance of hot switching could be a real potential
> benefit, but maybe the nature of recorded voice is such that you don't get
> full drive right away anyhow.

I don't think the delay is necessary on SSB, just don't talk during
the first 15 milliseconds of recording a message.  Feed the DVK/DVP
PTT signal into the footswitch port with the mode set to NORMAL and
you are done.  You can keep your footswitch connected using a Y adapter.

Tree

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