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Owen Duffy · March 6th 07, 05:42 PM posted to rec.radio.amateur.antenna

wrote in news:1173187467.306167.194350
@j27g2000cwj.googlegroups.com:

Does anyone have any smith chart tutorials that are easy to follow as
i have some technicians who require some study aids, most of the
tutorials around are a bit over burdened with math.

I think you are asking for a tutorial on how to apply the Smitch chart
without needing to understand transmission line theory.

I am sure that one could teach a person the mechanics of solution of
specific problems, but that is all they will know rather than how to
apply the Smith chart to the solution of problems generally.

Today, when computer power allows precise solution of problems that were
pretty ugly on slide rules, the real benefit of the Smith chard IMHO, is
as a visualisation tool. If you take away the understanding that gives
its value as a visualisation tool, you have a crude graphical solution to
problems that can be more precisely and more conveniently solved with a
computer program (whether or not it displays results on a Smitch chart).

Did I say crude? Yes, graphical solutions on a Smith chart are prone to
gross error in some parts of the chart. That downside is to some extent
masked by the accuracy of the "known" quantities being plotted, but
software that solves the transmission line problems, including applying
line loss, are more accurate on high VSWR problems. People like McAlpine
worked at approximations of high VSWR scenarios to overcome the
shortcomings of that area of the Smitch chart, but that is not really
needed today, just solve the exact equations in a computer program.

That is not to say that there isn't a place for Smith charts, but IMHO
the greatest value is as a visualisation tool, and that requires an
understand of the underlying maths, but not the tedious solution of the
underlying maths.

Owen