Bob:
Could you send me that QST article, I have been looking for it.
Thanks Ed K7DXV ewell2@cvc.net
----- Original Message -----
From: "Bwana Bob" <wb2vuf@qsl.net>
To: <tentec@contesting.com>
Sent: Thursday, May 01, 2003 6:40 PM
Subject: Re: [TenTec] Scout modifications
> There was also a mod described in QST that helped with the drift issue.
> I'll forward it to you if you like. Actually I didn't have much trouble
> with the keyer, but when I used an external straight key I had a rapid
> and severe drift as the heat from the final warmed up the PTO. The QST
> mod keeps the FLS circuit active during transmit with an external key.
> It just involves moving some wires around.
>
> Bob WB2VUF
>
> Stuart Rohre wrote:
> >
> > Some Scouts can benefit from having adjustments to the NPO type caps to
set
> > minimal drift in CW mode. See the manual for why a PTO drifts in the
Scout.
> > The computer can only correct it up to about 25 wpm code speed, unless
you
> > pause periodically in sending, (which most folks would do anyway). That
> > gives time for the PTO to be corrected for any heat drift. Otherwise
there
> > will be a step correction at first pause. If you adjust the NPO type
> > compensation to minimize drift from normal heating, you do not have to
> > correct the PTO as often.
> >
> > Just adding a fan blowing on the heat sink when running 50 watts will
help
> > the PTO stability some have found. I guess it keeps conducted heat from
the
> > front of the radio here the PTO is.
> >
> > Other mods are to place a pot for the fixed resistor that sets RF gain,
and
> > to place an outside pot to adjust power, replacing the on board bottom
> > facing trimpot. Use of flat cable allows the 3 pot leads to be run out
the
> > back of case between lid and back wall to a bracket mounted pot.
Another
> > version makes the mike gain a fixed resistor and uses that 10 k pot to
> > replace the power pot.
> >
> > If you mainly run SSB, you will not need to do anything to the PTO about
> > thermal (normal) drift of the LC circuit. The computer will correct.
It
> > only comes up in CW because the computer also runs the keyer, and there
is
> > not enough time at speeds above 25 wpm to do both. However, who runs 20
> > plus words per minute without pauses? I think it is more of a possible
> > concern than a real concern, as the instructions point out the simple
fix,
> > pause in your sending.
> > 73,
> > Stuart K5KVH
> >
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