[TowerTalk] more info on Re: 75 meter antenna

[Tom Rauch]

> Well Tom I don't want to besmerch the ARES volunteers but
perhaps they
> don't have the antennas tuned.

You can easily give up 6 to 10 dB with a dipole below 1/10th
WL over normal dirt. One sure clue that is happing is when
feed impedance remains reasonably high.

> also tried inverted Vs,  etc. the NVIS  blows them all
away.  Get on 40m
> some time Tom.

So is your 40m antenna 25 feet high? If so, that's almost
.2WL.

If I was going to put up a *low* NVIS antenna I'd lay down a
screen of wires spaced every few feet and parallel to the
antenna. It isn't necessary to tune them. If I was going to
install a reflector (which wouldn't work any better than a
non-resonant reflector screen lain on the ground) , I'd keep
it high enough above the earth to ensure it coupled to the
driven element much better than the lossy dirt.

Those are my only points.

73 Tom