[Elecraft] Home made Sigma-GT5 & KRC2 or SGC?

[Earl W Cunningham]

Don, W3FPR wrote:

"I will be using elevated radials rather than trying to install a good
in-earth grounding system of 120 radials. Full quarter wave 20 meter
radials will be quite practical for me, but I may be able to see what
difference shortened (and tuned) radials (and perhaps even 3/4 wave
radials) produce (if any) for my particular soil characteristics here in
Wake Forest, NC."
==========
Al Christman's (KB8I) assertion that a few radials close to the ground is
equivalent of the ideal (120 radials 0.4 waves long) buried radial system
has turned out to be wrong.

It has since been proven (by field strength measurements far from the
antenna and by modeling using NEC4) that elevated radials less than 0.5
wavelengths above ground are only slightly better than the same number of
on-ground or buried radials.  Therefore it is advisable that if you use
elevated radials, then use a lot of them, just as you would do if they
were on the ground.

On the other hand, it has been shown that shortened elevated radials
resonated with a loading coil has only a small effect on the efficiency
of the radials as compared to long elevated radials.

Rather than a separate coil in each radial, some have reported good
success by tying all of the short radials together and loading them to
resonance as a unit with only one coil.  The apparent reason that this
method is chosen by many is that is is very difficult to individually
tune every radial exactly alike and only one or two of the radials will
"hog" the ground return currents.

73, de Earl, K6SE