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Determining if reactance is capacitive or inductive.

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December 20th 06, 06:13 PM posted to rec.radio.amateur.antenna

Richard Clark Richard Clark is offline

Richard Clark is offline

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First recorded activity by RadioBanter: Jul 2006

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Determining if reactance is capacitive or inductive.

On 20 Dec 2006 09:16:47 -0800, wrote:

I thought the SWR curve looked strange as well. The SWR has a weird
curve across the entire band. The antenna is actually a 4 element quad.
Its fed with a W2DU style VHF 1:1 balun.

Hi Scott,

Well, I can plainly see the BalUn in the first picture. To be
completely decoupled a second one a quarterwave away on the feedline
would help, but the numbers look far more whacked out than that might
cure (because it probably isn't the problem to cure).

The coax is a short run of
RG-8X. The RG-8X uses PL-259s on both ends and I soldered a SO-239 onto
the coax for the balun (see pictures). Any issue with using PL259s and
a SO239?

I notice from the picture you don't seal anything. Those connectors
are leakier than a sieve.

Aside from these comments, perhaps you should validate your meter by
measuring known loads. It sounds simple, but in the VHF it is not.
Common garden variety components like resistors and capacitors have
values that diverge greatly from their markings. So, some care in
their selection (or construction) is warranted.

Anyway, grabbing components out of your junk-box would serve as a
first pass attempt, but it shouldn't end there.

73's
Richard Clark, KB7QHC

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