Topband: GAP Vertical Question

[Donald Chester]

From: charlie-cunningham at nc.rr.com

 Could you support a vertical 1/2 wave for 160 with aballoon? 
You could end -feed it at the base through a 1/4 wave of 450 ohm
ladder line and it would be a FEARSOME 160 antenna!  And the whole radial issue goes away!!  
I've operated a vertical 1/2 wave for 40m this way with
GREAT success!...

Probably would be a great antenna as long as the bottom end is elevated well above  ground, basically forming a vertically oriented end-fed zepp, something that might actually be feasible with balloon support if the winds are calm.

But feeding a half wave vertical with the base near the  ground still  results in substantial ground losses without a radial system.  True, it may be self-resonant and not depend on the ground plane to supply the "missing half", but with the presence of lossy earth in the close vicinity of the radiating element, much of the rf power is wasted warming the earthworms, as the earth and its resistive loss provides the majority the return path of rf currents to the antenna base. 

Another way of looking at it is to think of the ground radial system as a highly conductive shield inserted between the lossy earth and the radiating antenna, carrying the return currents while by-passing most of the ground resistance in the return path.

Don k4kyv