At my old QTH in ILL, I used a fed tower with 4 elevated radials, they
were about
12 foot off the ground, it worked fairly well, but I started adding
radials on the ground,
as I added radials the feed point impedance changed, I hit diminishing
returns at about
60 radials, the difference between 4 elevated and adding the 60 on the
ground was
more than the equivalent of doubling my power. so at least 3DB for
me. YMMV..
The raised radials were very "hot" I could draw a 2 to 3 inch spark off
the ends
easily so make sure they are insulated and out of reach of humans.
Almost set my garage on fire as one radial arced over to the roof
flashing close to where
it was tied off.
I find a big difference in 160 compared to a 4 radial GP type system on
40 meters,
maybe if the radials were much higher and less coupling to the ground
they would work
better.
73 Merv K9FD/KH6 KH7C
> On 5/4/2012 5:52 PM, James Rodenkirch wrote:
>
>> What about radials above the ground? Like what I'm planning to install ---
>> base of the vertical at around 5' to 6' above ground and slope all of the
>> radials from that 5' or 6' point down to the ground?
>>
> N6LF has published extensive work that he did on 40M showing that
> radials elevated only a feet or so were quite effective, and that a foot
> higher was better, but close to many radials on the ground. I tried
> scaling this to 160M, placing radials at about 5 ft. They were NOT
> particularly effective, and I had the chance to discuss the issue with
> N6BT, who has studied elevated radial systems extensively on 160M.
> Paraphrasing Tom, the earth at 160M is a rather different animal than it
> is at 40M. Tom suggested that 16 ft was a better height for a few
> elevated radials on160M, and I hope to move the ones on my experimental
> antenna to that height in the next month or so, perhaps even before
> leaving for Dayton.
>
> 73, Jim K9YC
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
>
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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