On Tue, 05 Apr 2005 08:25:09 -0400, Vinnie S.
wrote:

But to answer your question, your particular type of antenna, like the
A-99, is designed to decouple with no radials. Adding radials to this
type of antenna does very little to improve performance. It's more
about marketing hype than actual performance improvement.



I should have been clearer. I wasn't trying to improve performance, since it is
a 5/8. But from the reading I have done (no thanks to anything Frank posted), I
was simply seeing if thise would lower the angle of radiation, and reduce
potential for any king of interference. I am sorry id my lack of knowledge in
this field, insults Frank.


Well we all can't be masters of every facet of electronics and radio.
And those who are weren't always that way. Most of us learn a few
things every day or so.

That being said, I'll have to look in the archives, but I recall a
discussion some time back about exactly what you are proposing to do.
The consensus at that time, by those who seemed to be in the know on
the topic, was that those type of "stick" end-fed radial-less 1/2 wave
and 5/8th wave antennas were designed to not need radials, and adding
them affects them very little in the areas that matter. The A-99
especially has poor decoupling which allows the feedline to radiate to
some degree, which is why people claim that the antenna "bleeds".
Simply adding radials does not seem to affect the transformer
decoupling all that much and doesn't really help the problem.

I don't know if the IMAX suffers from the same issues, but you might
want to search around for some discussions on them. You might pick up
some useful information.

Personally, I much prefer the "old fashioned" Sigma 5/8th style
antenna with radials. Jay's Interceptor 10K antenna seems to be about
the best thing going these days.

Dave
"Sandbagger"
http://home.ptd.net/~n3cvj