> I was planning on 4el SteppIR and an XM240 on a 70ft AN Wireless
> tower then I got to thinking about feeding the tower for 160m and
> using the beams for toploading. That won't work too well if the
> dimmensions and thus toploading provided by the SteppIR change all
> of the time so I'm now looking for traditional beam designs.
The SteppIR elements are all insulated from the boom. As such,
unless your antenna switch shorts all unused antennas to ground,
the only contribution to top loading is from one side of the driven
element and the boom (32' for the 4 element SteppIR) is the dominant
contributor to any top loading from the antenna.
Similarly, with a 22' boom and insulated elements, an XM240 mounted
12 to 15 feet above a 4 element SteppIR will tend to dominate the
top loading (12' + 11' = 23' vs. 16' for SteppIR).
If you really want to try to model a shunt fed tower with the XM240
and 4 element SteppIR, drop me a direct e-mail and I will send you
some specific parameters (and considerations) for the SteppIR.
> Since Cushcraft is the only manufacturer to my knowlege that
> provides manuals for the products online,
The SteppIR manuals are all on-line as are HyGain's manuals.
... Joe, K4IK
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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