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Re: Topband: Shunt fed tower plus Marconi vertical phasing on 160 and80?

To: "Paul Staupe" <pstaupe@qwest.net>, "topband" <topband@contesting.com>
Subject: Re: Topband: Shunt fed tower plus Marconi vertical phasing on 160 and80?
From: "Tom W8JI" <w8ji@w8ji.com>
Reply-to: Tom W8JI <w8ji@w8ji.com>
Date: Thu, 30 May 2013 19:02:13 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>
I'm assuming the 1/4 wave on 160 would be about 130' which would be a half
wave on 80 and that they would have to be fed via different networks.

Has anybody done this?  Does the shunt fed tower work in a phased array
situation, or would I be better off just using the insulated tower as a
Marconi single element vertical?

I don't know how deeply you understand directional arrays and networks, but you could probably make it work with a couple T-network tuners and some relays just by cut and try. It might take a little fiddling around listening to signals, but there will always be a combination of what you could do with a T network or two that would provide deep nulls.

It is more "cookie cutter" to use series fed quarter wave elements with current feed (95% of people still do that wrong), but if you have a little patience and don't mind experimentation, you could certainly make it work. I phased dissimilar elements many times over the years, with the grossest mismatch a "T" phased against a shunt fed tower. All it takes is parts and patience. :-)

73 Tom
All good topband ops know how to put up a beverage at night.
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