Hi Rob,
To get all the facts go to http://www.antennasbyn6lf.com/ and read the
Pacificon presentation. Enjoy!
73 Bert, VE3OBU
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Rob Atkinson
Sent: Monday, January 12, 2009 6:59 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] in or on ground radials v. elevated (was:
InvertedL)
hi,
this is one of those questions that hams will discuss forever. search the
list archive (you can probably use the keyword "elevated" to get previous
posts about this pro and con).
here's an interesting statement about elevated ground systems (scroll down
to see it):
http://www.amgroundsystems.com/agsc_index.htm
Now, granted, he's selling his service for installing in-ground radials and
this pertains to medium wave broadcasting but there are still some points
hams can use.
For one thing, he says they need to be elevated 12 or 15 feet.
Actually I think that's low. I'd say they need to be more like 25 feet up
to work on 160 for if they are not sufficiently isolated from the surface,
they cease to be "elevated" in the RF sense. 10 feet is no distance at all
when the wavelength is 500 feet -- that's essentially like laying in the
ground.
Another thing I like about ground level radials is length no longer matters
in the sense that the radials are not a tuned part of the antenna system.
Length therefore only matters as far as increasing returned current is
concerned. Of course the downside is that you need a lot more. Now if you
can get your feed point high enough and you can suspend 4 radials pretty
high up there then give the elevated thing a try. If it tanks you can
always go back to plan A and put a bunch more on the ground.
73
rob / k5uj
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