I do not agree on the elevated radials as being overrated, for Arizona
desert anyway. I had my 40m 4sq installed with 8 buried radials under each
element. The tuning method for the array was to erect all elements
identical, observe the frequency where the least amount of power went into
the 5th port (the dummy load) in each direction, apply a little Kentucky
windage and adjust the vertical elements lengths (all equal) to the desired
operating frequency. I never could observe a frequency where the wasted
power was minimum in any direction, and I was never happy with the array's
performance.
When I moved to the present location I decided to try again but with
elevated radials. I put up 4 tuned radials at 9 feet elevation under each
element and the array tuned sharply and works very well. Good enough that I
decided to build an 80m 4sq also. And I am very happy with it's
performance.
And my RG-213 feed line and RG-11 foam impedance matching
transformer/phasing lines do not get hot, even running full power cw during
a contest (I only run 800 watts on RTTY).
I think the important thing here is he wants an effective antenna and in my
opinion he will be very, very happy with 4 or even 8 elevated radials under
each element, provided they are at least 9 feet above ground.
Further, I will caution him to electrically measure the 1/4 wavelength lines
rather than use the formulas. The lines on my 40m 4sq are stretched taught
between the phasing box and the element feed points and according to the
formula they should have enough slack in them to touch the ground.
de Paul, W8AEF
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Tom Rauch
Sent: Friday, October 22, 2004 12:51 PM
To: Yo3ctk; towertalk@contesting.com
Subject: Re: [TowerTalk] Ground radials/elevated radials
> The same would hold true for elevated radials?
Elevated radials are overrated. Unless you can get them up
1/4 wl or more in the air, you will still contend with ground losses when
you only use a few radials. Also the system is NOT fully unbalanced when you
use a small counterpoise. It is in the murkey land of not being balanced and
not being totally unbalanced.
> I am designing a 4-square for 80m. Full size verticals.
Comteq
> phasing/switching unit. But I need elevated radials for
practical reasons
> (the land below is used for small-size agriculture). I am
not sure how many
> and how long radials are needed for each antenna. I am not
after the
> ultimate system, only one with decent results.
When I tested systems at a few locations, I found I needed about 15-20
elevated radials (up about 6 ft) to equal 60 on the ground. You will still
need a choke or current balun to cool off the feedlines in some cases even
with 15 radials.
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