Tom,
I will be interested to see what the solution(s) will be for the BC station
interference.
Wanted to thank for the reference to the impedance problem calculators. They
are great!
73,
Bob
K6UJ
On Nov 2, 2012, at 2:21 PM, Tom Boucher wrote:
>
>
> A ham friend asked me to design a matching network for his 160 metre end fed
> quarter wave, so I asked him to provide an impedance reading using his
> MFJ-259B. I would then use the Berkley site
> (http://bwrc.eecs.berkeley.edu/Research/RF/projects/60GHz/matching/ImpMatch.html
> ) to provide the necessary values for an 'L' network, as I have done many
> times at my own station.
>
>
>
> The readings he provided were total nonsense and quite erratic, so we
> concluded his MFJ-259B was dead. He assured me that he always does a static
> discharge before connecting the MFJ.
>
>
>
> So I paid him a visit, taking along my Palstar Antenna analyser thing, which
> has always performed well at home, and what-do-you-know, the readings on that
> were also erratic, total nonsense and it behaved in a way I have never seen
> before.
>
>
>
> Than someone suggested the problem may be due to a 50Kw BC station on 909
> KHz, situated less than 5 miles away, causing both antenna analysers to
> misbehave.
>
>
>
> We ended up with a good old-fashioned link coupled parallel tuned circuit
> with the antenna tapped a few turns up from the ground end. This works fine
> but he is power limited due to arcing across the tuning capacitor. So we
> would ideally like to revert to the 'L' network plan, but how to use the
> antenna analyser in the presence of a high BC station field. Anyone any ideas?
>
>
>
> 73
>
> Tom G3OLB
> _______________________________________________
> Topband reflector - topband@contesting.com
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