FWIW,
I have implemented something similar with my own custom software for the
Pegasus. The software has an "auto tune" button. When you click on that,
the software places the Pegasus in CW mode, key down with a user specified
output power (a separate setting from the normal power out adjustment) and
then toggles the DTR line on the RS232 port to which the Pegasus is
connected. The DTR line is not used by the Pegasus. I built a cable with an
RS232 - TTL level converter (just like the ones commonly used for PSK31 PTT
control) and connect that to the AT-11MP. This starts the tuning process.
The Pegasus monitors the SWR until it stops changing which indicates that
the tuner has stopped, shuts of the RF and returns to the previous mode.
There's also a provision to time out if the tuner never stops. When the
tuner stops the software can examine the SWR to see if a match was found or
if the tuner just gave up on an impossible match.
I've not tried it with things like no antenna or a dead short, but for my
"real" antennas, it works like a champ. The AT-11MP usually finds a 1:1
match.
Another thing to consider is that when reading the forward and reflected
voltages, the Pegasus only returns integer values which makes it difficult
to get an accurate SWR with a low (20 watts or so) forward power. A
reflected power of 0 is (of course 1:1), a reflected power of 1 is about
1.5:1 and a reflected power of 2 is almost 2:1. There's no way to get
readings in between without a higher forward power.
Mark
----- Original Message -----
From: "j" <justo@maplenet.net>
To: <tentec@contesting.com>
Sent: Wednesday, May 01, 2002 9:43 AM
Subject: Re: [TenTec] Customer Requests for a Jupiter Wish List
> ----- Original Message -----
> From: "Rob Atkinson, K5UJ" <k5uj@hotmail.com>
> >
> > >have the AT-11MP find a match and then have the TT's 'Tune' feature
> > > >automatically shut off when a less than 1.5:1 match is reached.
> >
> > A programmer taking you at your word on this will program the radio to
> stop
> > tx and tuner adjustments at a match of 1.49:1 and not bother to try to
> find
> > a 1:1 match. Don't you want the radio to find the best match possible
> > before quitting? Admittedly there's not much practical difference
between
> 1
> > and 1.5 however.
> >
> > Rob Atkinson
> > K5UJ
> > k5uj@hotmail.com
> >
>
>
> rob,
>
> that's a good point. i'll make the correction.
>
> thanks to all for your input so far. i'll give it a few days to catch
> anyone else's ideas.
>
> 73,
> j
>
>
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