Reg Edwards wrote:

"AndyS" wrote in message
ups.com...

Andy adds:

I have often used a modified Smith Chart , called an
Impedance/Admittance
chart , to do matching..... If the impedances are not greatly
mismatched,
it is very easy and accurate.... and very very intuitive...

The ones I used have the impedance cordinates in black and the
admittance coordinates in red.....

I found them extremly useful in the design of an automated

antenna

tuner
which I designed for a Texas Instruments Marine SSB unit, back in

the

late 70s..... You could literally track the impedance transormation
mentally
with series and shunt elements.....

Andy W4OAH

==========================================
As an Engineer in my eighties with a long association with
transmission lines of all sorts I have never used a Smith Chart, in
anger, in the whole of my life. I have always used log tables,
sliderules, pocket calculators or, more recently, dedicated computer
programs.

Use of mathematics gives one a more 'intuitive' insight into how
transmission lines work than any chart. But it's a just a matter of
opinion and depends on one's basic education.

As useful as they were only at HF, Smith Charts became redundent when
the personal computer came in. Old habits die hard!
----
Reg.



Reg,
have you ever taken the time to learn _how_ to use one? Actually,
they're just as mathematical as the formulas you've always used, and,
for some people, just as useful.
73,
Tom Donaly, KA6RUH