Thanks to everyone for the responses to my question. There were posts to boith
Topband and Towertalk as well as several sent just to me.
The responses ranged from you will probably never make it work or you need to
drive both elements to it will work according to the computer model. Many had
suggestions as to how I should proceed in tuning it, cautions regarding the
ground system, etc. All the responses were thoughtful and had information that
was useful.
I played with it a little bit last night in the dark. I switched the parasitic
element in and out while listening to W1AW and it was difficult to see whether
there was any difference in the forward direction. I had no signal source to
the Southwest so worked with what I had. I then shortened the element by some
amount (perhaps five feet or so) and checked again. This time I could see a
difference and W1AW was best in the Omni directional state indicating to me the
parasitic element was now a director. Then I added back about ten feet or so
and W1AW was better with the parasitic element switched in. Now I am getting
somewhere. When I got up this morning I went out and disconnected the shunt
feed on the tower and used an MFJ analyzer to see what that wire element looked
like. It looked like it would show least reactance a little below the lowest
frequency the analyzer would tune - maybe 1750 or so. I took a couple feet off
and it now shows a small amount of reactance a
nd about 28 ohms at 1785. Does this give any indication of how adequate the
ground system may be? I didn't measure anything but think the element is
probably 2-3 feet longer than it originally was.
The F/B is insignificant and is of no interest to me since I am going to listen
on Beverages. Maximizing the F/B would only be useful if it would correspond
to highest forward gain or if it were known to be say 30 Khz above the point at
which maximum gain would occur so I could trim or add accordingly. With the
tools I have available I think it would be difficult for me to see a small
difference in forward gain from one frequency to another. It may only vary a
small fraction of a dB over 20 khz. The computer model would not indicate
major changes in what little F/B there is over that range either.
I am thinking that if the element shows to be resonant somewhere between 1775
and 1790 and I can see a small but noticeable movement up in the S meter
reading on NE stations when I switch the element in, I have done about all I
can do unless someone has a practical suggestion as to how I can quickly
squeeze our that last dB of gain that may be available somewhere between 1800
and 1900 and move it to 1830.
Thank you for the suggestions. Since I posted to both reflectors, perhaps the
best thing would be to send a response just to me in case this is boring to
some.
73...Stan, K5GO
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