[TenTec] Auto Tuners

[Frank Kirschner]

On Sun, Oct 3, 2010 at 8:59 PM, Dr. Gerald N. Johnson
<geraldj at weather.net>wrote:

> Check their specifications. I think they insist on tuning at low power
> to preserve the lives of the tiny relays they use. That they can carry
> but not switch 100 watts. And then tuning with a couple watts, cuts
> transmitted QRM compared to tuning with 100 watts.
>
> Yes, that's exactly it.  Also, if the SWR is very high, the voltages inside
the tuner can easily exceed ratings at 100 watts.


> The two manuals I just checked talk about rig protection rather than
> tuner protection but I think the tuner is destructible too.
>
> TT rigs don't fold back when mismatched unless the PA collector current
> trips the circuit breaker or the current limit in the power supply.
>
> Since the automatic tuners will tune with 0.1 watt, why make QRM, why
> not cut the power way back for tuning?
>

I have three autotuners, and they all specify a minimum of five watts for
tuning.  But they generally tune so quickly that it doesn't create much
QRM.  I stored all the frequencies I use in my MFJ-998, so when I QSY, in
almost all cases it tunes in well under a second.

Frank
KK4PR