[TowerTalk] Ground radials/elevated radials

[Tom Rauch]

> Perhaps I missed some previous messages in this thread?

I don't think you missed anything Paul.

If we know points of diminishing returns and the real cost
of not doing something, we make better decisions.

For example, did you know that if you use an elevated
resonant counterpoise the radials all radiate substantial
signal in the nearfield area? Did you know the more radials
you use the less problem that is?  Or did you think that
with a "balanced layout" the radials don't radiate?

Knowing the radials all act like antennas can help us plan a
system better. I'd never install other feedlines or antennas
parallel and close to a system using a few radials, knowing
that. I'd never  bring a radial near a telephone line or TV
antenna feedline. If I thought the radials was "perfect", I
might make a mistake and do that.

Did you know that you lose field strength with elevated
systems if you don't use a choke or current balun to isolate
the system from earth? I don't see many people isolate
feedlines from the feedpoint of small radial systems, yet it
can be as much as a dB or so change!

Like the comments before none of this says "don't use them".
It just points out the quirks of using a sparse radial
system of any type and things you have to watch for.

If you look at:
http://www.w8ji.com/verticals_and_baluns.htm  and
http://www.w8ji.com/end-fed_vertical_j-pole_and_horizontal_zepp.htm
you'll see how important it is to isolate feedlines even  on
groundplanes with four radials.

I hear people constantly saying with four radials 1/4 wave
or higher off the ground the radials are "perfect", and I've
even heard people say "two radials are actually enough, they
only used four on a groundplane because it looks better".
Some antennas are even sold using end-fed radiators without
any radials!

At some point someone has to learn how the stuff really
works in order to make good decisions, even if they are
decisions on where and how to compromise.

73 Tom