> Gentlemen, Measuring the F/B of any HF antenna in the
E-Plane only, is
> at best a guess. The only true way to know the real F/B is
measuring it
> in the H-Plane, and there is the problem.
I'll second that comment. The worse possible way to measure
horizontally polarized HF or lower frequency antennas is at
large distances over earth. The longer the distance, the
more likely you are to have an error.
Somehow we seem to have the misplaced notion that groundwave
works with horizontal, and that measurements must be made at
distances of a mile or more.
First of all, no one should care what gain or F/B is at a
mile or more along the earth. A groundwave null is useless
for skywave operation.
Second, any vertical component has much less attenuation
along the earth. The earth actually acts like a filter or
attenuator for horizontally polarized waves.
I know a fellow who swore he hit the best antenna feed
system in the world, because he picked up 20-30dB on a
groundwave path over using a balun! There is no doubt at all
he made the feed system worse and the feedline is now
radiating, because there isn't a balun or tuner in the world
that would suck up over 99% of the power without something
nearly melting at only 100 watts. Even 50 watts of
dissipation is devastating to the components primarily
responsible for loss, unless they are huge components.
Measuring at one or two wavelengths distance would be much
more accurate than at a mile.
73 Tom
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|