[Elecraft] KPA500 troubles

Jim Brown jim at audiosystemsgroup.com
Sat Nov 14 00:01:04 EST 2015


On Fri,11/13/2015 1:30 PM, Wes (N7WS) wrote:
> Note, there is no mention of any directivity, or lack thereof, so I 
> would take it that this is a theoretical free-space value.

One could do that, of course, but your original post brought ground 
conductivity into the computation, which is, IMO, entirely appropriate.

FWIW, I've done some extensive modeling studies of horizontal and 
vertical antennas at various mounting heights; horizontal antennas don't 
care much about soil but care a lot about height; vertical antennas care 
a bit about height and a lot about soil. That work is on my website.

I think I would use average gain of the antenna as installed as the 
basis for compliance with the Rules, but the question remains, what 
height for the dipole? :)

This is, for me, purely academic. My soil being terrible, a vertical is 
a poor choice for 60M, and I have a bunch of high horizontal dipoles, so 
I'd use one of them. :)

BTW -- there's a 2-part piece on this topic by Rudy Severns in QEX this 
past summer, specifically addressing very short verticals for the 630m 
band.

73, Jim K9YC


More information about the Elecraft mailing list