Because my old grounded-grid sweep-tube amplifier doesn't present a good
50-ohm match at its input, I will run an auto-tune on the current antenna if
I'm running barefoot, or run an auto-tune on the linear amplifier if I am
going to be using that. That's in addition to reducing the power from 100
watts to about 50 when driving the linear. I don't use any sort of antenna
tuner between the output of the linear amplifier and the antenna. In
general, your transceiver will see a different load when comparing the
antenna (barefoot operation) to the linear amplifier's input. So for
maximum power transfer, you may want to readjust the transceiver's tuner
between the two conditions on a particular frequency. The tuner in the
FT-950 is only rated for 3:1 SWR maximum, but I've seen it work into some
SWR's that are higher than that.
I'm not sure what Maurice is talking about, although if you don't get a good
match between your rig and an antenna, your signal is going to be quite weak
and noisy.
73,
Lloyd Rasmussen, W3IUU, Kensington, Maryland
Home: http://lras.home.sprynet.com
Work: http://www.loc.gov/nls
> -----Original Message-----
> From: For blind ham radio operators [mailto:[log in to unmask]]
> On Behalf Of Steve Dresser
> Sent: Monday, November 29, 2010 10:49 PM
> To: [log in to unmask]
> Subject: Re: Looking for a blind friendly antenna tuner?
>
> Tom,
>
> The internal tuner would indeed be vaporized if it were actually connected
> to the amplifier's output, but it is not. Actually, the problem with
> trying
> to use the internal tuner while running the amplifier is that you would be
> trying to match the output of the radio to the input of the amplifier
> rather
> than matching it to the antenna. Even if you were using a linear that
> only
> generated 100 watts, you'd have to bypass the internal tuner because your
> antenna is no longer directly connected to the radio while the linear is
> in
> use.
>
> Steve
>
> ----- Original Message -----
> From: "tom behler" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Monday, November 29, 2010 21:16
> Subject: Re: Looking for a blind friendly antenna tuner?
>
>
> > With all due respect, I agree with what Howard is saying here.
> >
> > I have found the auto-tuner in the TS480 to be very forgiving.
> >
> > I do use a manual tuner as well, but only when using my Ameritron Al811H
> > amplifier, since the auto-tuner in the TS480 would probably be vaporized
> > with the higher power level.
> >
> > 73 from Tom Behler: KB8TYJ
> >
> > ----- Original Message -----
> > From: "Howard Kaufman" <[log in to unmask]>
> > To: <[log in to unmask]>
> > Sent: Monday, November 29, 2010 9:14 PM
> > Subject: Re: Looking for a blind friendly antenna tuner?
> >
> >
> > What does a signal to noise ratio have to do with a tuner?
> > The tuner in the 480 will tune anything under 8-1. They have no idea
> what
> > they are talking about!
> >
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