Computer alternative to Smith Chart?
 

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

Computer alternative to Smith Chart?
 

"Tom Donaly" wrote
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.
=======================================
Yes. Many years ago I attended a lecture. The lecturer handed round
Smith Charts as a tutorial. We spent 10 minutes on it. But these days
I'm well out of practice.

The Smith Chart was only of any use at HF and above. That's what it
was invented for. Fine for radio amateurs who only use the HF bands
and above. It followed on from previous, more complicated Victorian
Age charts to ease calculations involving complex Hyperbolic
functions. Very good while it lasted.

Small, dedicated computer programs these days are more accurate and
time saving than charts and their 'what-if' operating procedures are
much more educational.

But I appreciate the sentimental attachment, indeed affection, many
old timers have for the good old Smith Chart. By all means carry on
using them.
----
Reg.

Computer alternative to Smith Chart?
 

I think that is the engineer in you speaking!

I find the Smith Chart interesting as a tool. I am more interested in
how it works while you are interested in what it is good for!

My desk drawers still contain a couple of slide rules, a polar
planimeter, a drafting set and a Kurta Calculator. In spite of being
surrounded by an assortment of computers, I keep a good battery in my
HP Calculator and I remain fond of nomograms.

The Smith Chart is a tool. I cannot possibly have too many tools...

Of course I have archived the programs at g4fgq as well...

We could quit teaching Calculus as well, Computers make quick work of
graphic solutions!

On Tue, 11 Jul 2006 17:28:24 +0100, "Reg Edwards"
wrote:


The Smith Chart was only of any use at HF and above. That's what it
was invented for. Fine for radio amateurs who only use the HF bands
and above. It followed on from previous, more complicated Victorian
Age charts to ease calculations involving complex Hyperbolic
functions. Very good while it lasted.

Small, dedicated computer programs these days are more accurate and
time saving than charts and their 'what-if' operating procedures are
much more educational.

But I appreciate the sentimental attachment, indeed affection, many
old timers have for the good old Smith Chart. By all means carry on
using them.
----
Reg.

John Ferrell W8CCW

Computer alternative to Smith Chart?
 

John Ferrell, W8CCW wrote
I think that is the engineer in you speaking!

I find the Smith Chart interesting as a tool. I am more interested
in
how it works while you are interested in what it is good for!
============================================
John, you've weighed me up fairly well.
On the other hand I see much beauty in Mathematics. And program source
coding is the labour of love and a Work of Art. But Maths is a much
neglected subject in our Western schools and universities these days.
Even teachers don't know what five sevens are - and that's only
arithmetic.

I once asked a prospective Member of Parliament just before a General
Election what seven nines are. He didn't know. He lost his £500
deposit. Didn't get enough votes. Otherwise he might have ended up as
Chancellor of the Exchequer.
============================================
My desk drawers still contain a couple of slide rules, a polar
planimeter, a drafting set and a Kurta Calculator. In spite of being
surrounded by an assortment of computers, I keep a good battery in
my
HP Calculator and I remain fond of nomograms.
============================================
My Casio scientific calculator must be about 10 years old. I've never
changed the battery.
============================================
The Smith Chart is a tool. I cannot possibly have too many tools...
============================================
I bet you are an amateur carpenter as well.
============================================
Of course I have archived the programs at g4fgq as well...
============================================
Don't throw away your old computer. Being DOS programs there are
ominous signs they won't work too well on new versions of Windows.
============================================
We could quit teaching Calculus as well, Computers make quick work
of
graphic solutions!
============================================
I deliberately avoided graphics. Graphics depend on screen driving
software thus losing portability between machines.

My favourite Victorian is Oliver Heaviside. He invented the beautiful
Operational Calculus which magically transforms ordinary calculus into
simple algebra and converts functions of frequency on transmission
lines into functions of time. Now everything is going digital at
Megabits per second he was about 130 years in advance of his time.

All the best to you and yours.
----
Reg, G4FGQ.