On Oct 24, 7:33*am, Cecil Moore wrote:
Owen Duffy wrote:
Where an impedance range is loosely specified as you quote (dimensioned in
ohms without identification of the R and X parts), and in the absence of
applicable frequency constraints and loss figures, I think you can safely
disregard the information as unprovable advertising hype.

It is intended to look technical, something to impress the new wave of hams
who don't have the understanding, and not enough to reliably determine the
suitability of the ATU to a specific application.

The matching range of a typical tuner can be estimated
by playing with the simulated tuner at:http://fermi.la.asu.edu/w9cf/tuner/tuner.html
Select the frequency and load needing to be matched,
click auto, and see if the tuner can match it.

I wonder if Kevin would be interested in making the
tuner's CLC values user specifiable?

I have modeled tuners with Microsmith (an old DOS
program) and varied the C1, L, C2 values while watching
the trace on the Smith Chart. Given all possible
combination of CLC values, the result would be the
matching envelope of the tuner at a specified frequency.

What would be nice is a program that would automatically
plot the tuner's matching envelope on a Smith Chart given
the input parameters.
--
73, Cecil *http://www.w5dxp.com

There used to be a ham near me that use an auto tuner to feed a
doublet. I dont think the antenna was cut for any particular frequency
just the most wie he could get strung from corner to corner of his
yard. He found he could get it to tune up on all the HF bands but only
by changing the length of his feedline between the tuner and antenna.
I was thinking it may be nice to have a tuner that could control an
external relay to switch in/out custom networks for adapting it to
site specific operating conditons.

Jimmie