On 28 Apr 2006 08:52:31 -0700, "
wrote:

Hi Dan,

There are so many red lights going on, this was impossible to pass up.

I've found some sources that say that the auto tuners tend to have a
wider efficient matching range than the typical manual tuner.

Unless "they" can tie this to known antenna impedances, such claims
are worthless. And for another, what are the "typical" tuners that
are being compared to? Its easy enough to say what they are if it was
easy enough to measure them to support this claim.

So it may have nothing to do with network topology, it's just that if
you can manage to match a very short unloaded whip with your typical
manual tuner, you're going to be out at the edge of the matching range
where it is quite inefficient.

Matching and effeciency are only distantly related. Using padding
resistors could pull any antenna into a match - not much efficiency
there.

What's the group experience with this? If it's true that the automatic
tuners tend to be more efficient for a given range of impedances, what
are likely reasons?

There's a sucker born every minute?

Can the typical auto tuner switch from LCL tee to CLC tee? Pi to Tee?

That would have seem to have answered itself if your survey of
different auto-tuners was useful. Barring these results being
obvious, it would seem you simply discovered the font of Marketing
hype.

Is it always going to be better to use a binary switched inductor and
capacitor system as opposed to a variable capacitor/tapped inductor
system?

Depends on the granularity. Binary could mean one of two, or one of
1024.

Maybe it's just that the latter usually gets shoved into a tiny box and
the inductor Q is ruined?

For auto-tuners, that should be evident - and a marked counter to the
claim of greater efficiency.

73's
Richard Clark, KB7QHC