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Old April 18th 07, 10:35 AM posted to rec.radio.amateur.antenna
Owen Duffy Owen Duffy is offline
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First recorded activity by RadioBanter: Dec 2006
Posts: 1,169
Default multiband vertical

"Andre & Sharon Walker" wrote in
:

Hi all, I am just about to get my Foundation licence and am
contemplating a multiband vertical. Many plan talks about "radials"
being needed, now I just happen to have a house with a nice tin roof.
Can I make use of the whole roof as a ground plain or do I need
radials cut to resonance for each band?


Do you mean a trapped vertical or the like, or are you planning to use an
unloaded vertical on multiple bands.

If it is a trapped vertical, it probably comes with instructions. For
example, http://www.dxengineering.com/pdf/hus...5btv_instl.pdf
details the installation instructions for the Huster verticals.

You could read the instructions / manual after it doesn't work properly,
or you could read them beforehand.

Not all verticals require a substantial ground system, it depends on the
design. The tin roof might well provide a sufficient counterpoise for
some trapped verticals, depending on its size and location of the
antenna.

Short verticals are invariably quite narrow band on low bands, often as
little as 20kHz on 80m.

Also, keep in mind that verticals are relatively noisy in city
environments.

You might be well served with a simple coax fed dipole for one band (40m)
initially. Gain some experience, and note how many others are using
trapped verticals or the like. Do try to resist the end fed long wire
(though it is more correctly described as an end fed random length wire)
that seems so popular with FLs.

Owen