[BC] Directional Antenna Proofs - Ground systems.

[jpotter at jpotter.com]

Messrs. Fry & Meuser:

Roger your opinions, thank you. But my question begs: why use 120 radials when -- as it appears to be argued  only 2 would be satisfactory?  Major problem with that argument, but the economic implications are appealing!  Imagine the savings in copper wire!

"It would be interesting to learn why the tests mentioned in Mr Potter's post appeared to show such h-plane directional effects with only two rods in opposing directions in the horizontal plane."

The tests were conducted at Celwave, now extinct, then in Marlboro, NJ.  Before joining Celwave I had a commercial radio shop and had been a ham for many years.  There was an urban legend floating around by paging techs and hams that by inverting a wire ground plane antenna you could cause the radiation to be directed upwards toward the sky.  Celwave engineers arranged a test of this theory using one of their wire ground plane products and their test range. Result: nope!  And, furthermore, the horizontal (azimuthal angles) radiation followed the radials, with significant gaps between radials, regardless of elevation above or below the h-plane.  Don't know the theoretical justification, but that's the experimental evidence.  I am also persuaded that this effect is independent of (1) whether the ground plane is mounted on a pole high off the ground or resting on the earth, or (2) operating frequency.  Didn't test with buried radials, however.  Them's the facts, folks; read 'em and weep.

Regards/Jim Potter