TopBand: z measurements

[w8ji.tom]

Hi Goose,

Yuri's idea does work, if the load is a variable reactance in series with a
resistance. I often use small silver micas as the reactance reference but
it does require some experience with resonant circuits.

Be VERY careful not to bump or otherwise disturb the knobs, and to set the
frequency correctly. Most tuners have very high Q on 160.

A bridge is a better idea in most cases, since the most direct method of
measuring is usually the most accurate.

By the way, this might be a good time to remind everyone you can not use
the tuner to measure the impedance of a Beverage unless you measure the
high impedance frequency and the low impedance frequency and find the
geometric mean of those two impedances. That will be the approximate surge
Zo of the antenna. A single frequency measurement as pointed out on some
web pages will not work. 
 
> Yuri has a pretty good idea. There is one problem though.  Using this
method
> you can only determine the resistance of the antenna under test.  You can
not
> get any idea of what the reactance in the system is.  By using an
impedance
> bridge you can determine both the resistance and reactance of the system.

73 Tom

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