> One of the new Generals in town has purchased a 30ft
> pushup mast, the 4 band
> Hustler trap vertical (around 21.5 ft) and wants someone
> to install this for
> him with the mast bolted to a side of his house. Hustler
> shows elevating the
> antenna similar to what he wants to do (actually he wants
> someone else to do
> the work), with 2 radials for each of the 4 bands.
The goal of any antenna manufacturer is to sell antennas.
That's the payback they get for the work and investment they
It is unlikely anyone selling an antenna is going to give
the minuses, and ALL antennas have minuses, anywhere equal
weight with the pluses.
The only possible way to know if an antenna is really
working is to A B compare the antenna against a known good
antenna AT THE SAME LOCATION in many blind tests, or to
carefully measure things at a good clear test site. A good
marketing person will make the installation seem very simple
for everyone because most people won't know if the antenna
is 10dB down from something else.
You can see what happens with antennas having marginal
grounds, and even FOUR elevated radials far above earth are
a marginal ground so far as terminating the shield, by
looking at this page:
You can see with four perfectly symmetrical radials in a
perfect environment there is still nearly as much current
flowing over the shield (for some cable lengths) as there is
in the radials!! That current is about 20% of the current in
The closer to earth and the fewer the radials the worse this
This doesn't mean the fellow won't "get out", and he might
be happy with the system...but we shouldn't believe the myth
that a couple radials makes a perfect ground. That's a big
ole tall tale.
> I've tried to get him to ground mount the vertical close
> to the center of
> the backyard and put his radial system in the ground a few
> inches. He
> doesn't think that is a very good idea.
It's a complex picture Mike. He will gain signal level on
higher bands by getting the antenna up out of the clutter in
a yard, he will lose signal level on all bands...especially
low bands....by not having enough radials. He will also have
some feedline radiation, maybe even major feedline
radiation, unless he gets rid of the common mode current on
There is always guesswork when deciding what compromise is
the lesser of two evils. One guess is as good as another.
Out here in the open I don't worry about ground mounting, I
just use enough radials. There isn't any clutter. In the
city I would probably roof mount if possible and lay as
many radials as possible on the roof, or better yet use a
TowerTalk mailing list