Autotuners and transmitter longevity

[John Harper AE5X]

In another thread, W.D. (Doc) Lindsey wrote:

>Well I need IMMEDIATE help with my ATS-2.....Suddenly I could not get it to
>go into Tune mode, which is causing
>me some trouble setting up my automatic tuners.


With the popularity of external autotuners (T1, LDG, etc) among many of us,
I'm wondering what thoughts folks may have regarding rigs such as the AT
Sprints and KX-1 where the output power cannot be reduced prior to tuning.
Normally, when I tune for minimum SWR I lower the rig's output to protect
the finals if I expect SWR to be initially high. This isn't possible with
the AT Sprint and is inconvenient with the KX-1 (I know the KX-1 has a
built-in tuner and that power is reduced prior to tuning - I'm talking about
those rigs when used with external tuners)

Do you guys avoid using autotuners on rigs whose output can't be reduced or
do you use them anyway and just "take your chances"?

John Harper AE5X
Portable QRP: http://www.ae5x.com


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[Gil Stacy]

John,

What I do with the ATS3 and the T1 combination is to switch power sources
(batteries) to reduce output from 5 to 2 watts for tune-up.

73, Gil NN4CW


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[Don Wilhelm-3]

John,

Just a thought since I have no direct experience lately because I use the
Elecraft internal tuners or resonant antennas.

Many transmitters are self-protecting, and should withstand short intervals
of high SWR without harm.  Best to know your equipment because some can be
harmed.  If it is homebrew, you should already know the answer, and
commercial rigs should indicate something about the SWR handling in their
manuals.  As an example, the KPA100 reduces its power automatically if the
SWR is above 2.0.

73,
Don W3FPR

> -----Original Message-----
>
> With the popularity of external autotuners (T1, LDG, etc) among
> many of us,
> I'm wondering what thoughts folks may have regarding rigs such as the AT
> Sprints and KX-1 where the output power cannot be reduced prior
> to tuning.
> Normally, when I tune for minimum SWR I lower the rig's output to protect
> the finals if I expect SWR to be initially high. This isn't possible with
> the AT Sprint and is inconvenient with the KX-1 (I know the KX-1 has a
> built-in tuner and that power is reduced prior to tuning - I'm
> talking about
> those rigs when used with external tuners)
>
> Do you guys avoid using autotuners on rigs whose output can't be
> reduced or
> do you use them anyway and just "take your chances"?
>
> John Harper AE5X
> Portable QRP: http://www.ae5x.com
>
>

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[Ron D'Eau Claire-2]

Most well-designed rigs are protected against sporadic high SWR's. I'd be
much more concerned with arcing in the relays inside the tuner. Nothing
destroys relay contacts like switching them "hot". Elecraft's tuners reduce
output power during tune to minimize that danger. Like you said, that isn't
always the case with external or remote tuners.

Ron AC7AC

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