Topband: K2AV FCP with 43' vertical

[Tom W8JI]

> It's that thing about "at the top" that probably doesn't get past the
> "garden committee".  Folks don't really understand reactionary until
> you've crossed swords with the "garden committee".   Maybe something
> that slides INSIDE a fiberglass flag pole.

The major problem with ANY  43 ft vertical is it is nearly like a mobile 
antenna on 160. Unless the system has huge losses, RF voltages are off the 
map. With low-loss ground systems and loading coils, even the  voltage 
across a base loading coil is far too high for any reasonable relay.

(I know there have been articles that say otherwise, but I modeled systems 
and I actually tested several on 160 meters.)

With a modest ground system, high-Q loading coil,  and very good base 
insulator, and with only 500 watts applied, arcing distance for connections 
across the coil or from base to ground, was nearly one inch through 
moderately dry air at sharp points.

If I wanted to run higher power with a 43ft vertical on 160, I'd just add 
two or three wires from the top that could fold in and be tied to the 
antenna at the bottom. Then, on 160 and 80, they could be fanned out away 
from the base and a modest amount of base load used on 160.

Top loading with a "hat" not only gives *up to* four times the radiation 
resistance (reducing ground losses), it increases bandwidth and makes base 
voltages tolerable.

Or you can just do like the original design plan called for. Have so much 
distributed loss voltages never get high.

73 Tom