[Antennas] re: antenna tuners

Wed Nov 30 23:42:00 EST 2005

You dealt with a very limited number of antenna load conditions as far as I
can tell from your reply.
Your conclusion is likely the result of limited testing. Imagine if the two
capacitors were ganged together on the CLC system you just mentioned. How
would you get a match with one at full capacitance and the other not? How
would you know what the required fixed value would be?
It all depends upon the range of impedance values you want to match. More
degrees of freedom mean a greater matching range. You may have had some
"easy" matches to make and not required the additional matching range the
two separate cap design provides.
Chuck...K1KW
----- Original Message ----- 
From: "Robert Lay (W9DMK)" <w9dmk at crosslink.net>
To: "Chuck O'Neal" <cdoneal at comcast.net>; "Engel Hart" <va3kis at yahoo.ca>;
<antennas at mailman.qth.net>
Sent: Wednesday, November 30, 2005 11:07 PM
Subject: Re: [Antennas] re: antenna tuners
> > One less degree of freedom, meaning that the tuning range is less for
the
> > two knob differential cap design vs. the three knob separate cap design.
> > Of
> > course this depends on component values and circuit topology.
>> I'm sorry - no offense, but I cannot agree with that for two reasons.
> 1) I have several tuners of both types and have never had any more or less
> difficulty tuning a given antenna with one type over the other type.
>> 2) In EVERY instance of finding the proper tuning point on a C-L-C tuner,
I
> have found that one of the two capacitors is at full mesh.
> That means it could have been replaced by a fixed capacitor - so long as
> there was also a way to switch the configuration around, depending on the
> load.
>> So, in spite of the fact that I cannot PROVE it, I believe that the design
> with only one capacitor is as capable as the other.
> And, I think my observation of the behavior of the C-L-C tuners is
> sufficient to establish that there was an un-needed extra degree of
freedom
> in the design. In other words, the someone got clever with the simpler (?)
> design.
>> >> What is the difference between a regular antenna tuner
> >> that has two capacitor tuning knobs and a roller
> >> inductor, and one that has a differential capacitor
> >> tuning knob and roller inductor?
> >> I know the antenna tuner with the two capacitor tuning
> >> knobs can tune just about any antenna or wire. But
> >> I'm not sure about the differential capacitor antenna
> >> tuners. Can it tune anything as well?
>>> 73 de W9DMK - Bob Lay, Dahlgren, VA
> http://www.qsl.net/w9dmk
> w9dmk at crosslink.net
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