[TowerTalk] Antenna Analyzer Question

[David Gilbert]

That's every bit as technically correct  as anything I said ... it just 
requires that you cut a piece of coax to a particular length so it's not 
quite as versatile.

But just as valid.

Dave   AB7E



On 2/10/2026 6:59 PM, john at kk9a.com wrote:
> While not as technically correct as the responses from AB7E, K9YC and W6RMK,
> what I used to do back when I used Yagi's with hairpin matches was I
> measured the impedance through a 1/2 wl multiple of coax.
>
> John KK9A
>
>
> [TowerTalk] Antenna Analyzer Question
> Tom Hellem K0SN wrote
>
> In order to make measurements  of impedance, etc on an antenna with any of
> the various analyzers on the market, one must connect the analyzer to the
> antenna
> with some length of coax. And unless the antenna being measured has a
> feedpoint
> impedance of 50 +/- j0, the impedance as seen by the analyzer is going to
> vary
> continuously all along the length of the coax, a phenomenon easily seen
> with the use
> of a program like TLW, etc.
>
> Question is, unless I can attach the analyzer directly to the feedpoint,
> how can I
> obtain a reliably accurate measurement?
>
> I just looked at the user manual for one of the popular analyzers on the
> market.
> It makes no mention of this whatsoever. And I don't remember it being in
> any other manual I have seen in over 50 years of being in ham radio except
> for one:
> I have a manual for  a simple and inexpensive VNA built from a kit several
> years ago, sold by a German company, that makes a big deal out of doing
> what it calls an SOL compensation for
> the coax and any other connectors used between the VNA and the antenna.
> This
> supposedly removes any of the impedance transforming effect of the test
> setup from the
> equation and allows for a precise measurement of the antenna under test.
>
> So what gives? Has anybody here ever wondered about this?
> Am I overthinking it or is there something to it?
>
> Tom
> K0SN
>
>
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