Topband: Radial requirements for 1/2 wave vertical?

DAVID CUTHBERT telegrapher9 at
Fri Feb 19 10:01:16 PST 2010

Quarterwave & Halfwave verticals:

Theory and simulation say that a halfwave vertical will work almost as well
with a ground rod as with a good radial system.

My tests at 20 meters between a halfwave vertical and a reference antenna
followed by a quarterwave vertical and the reference antenna agree.

Having flown a few 160 meter balloon verticals and modeled them I contend
that a halfwave balloon vertical looks good in theory but may not be good in
practice. What gets the balloon vertical is that a small wind will push it
down to 30, sometimes 20 degrees. Model a quarterwave and a halfwave
vertical at this angle and you will see that the quarterwave is better.

However, a kytoon will fly high in a wind and would make a halfwave vertical
the clear winner over anything other than salt water. Fortunately for me I
do get to fly my balloon verticals over very salty water out beyond 100

    Dave WX7G

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