On Fri, 05 Dec 2003 16:44:04 GMT, "
wrote:

hmmm, this stuff I have read on NVIS says 0.1 to 0.2 wavelengths. I can find
the source if anyone is interested (I am not at home right now). I am
certainly not arguing (I have no problem arguing, but this is one of many
subjects about which I have very little knowledge), Richard, just mentioning
a difference in what I have read.

Paul AB0SI

Hi Paul,

The troops, during Desert Storm, achieved NVIS by laying the antenna
on the ground. I will add, that like Richard points out, it was sand.

Logic would suggest that an antenna very close to ground has no chance
of launching much energy tangential to the earth's surface (a direct
short), leaving what's left to go straight up and hazard a bounce from
above. If you raise that antenna to a quarter wave up, you simply
optimize the straight up radiation, but you also lose a lot of the
immediate ground loss that snubbed the tangential angles.

What few dipole users would admit (because they love to crow about not
having radials) is that if you add radials, you can further improve
your dipole performance up AND tangentially.

73's
Richard Clark, KB7QHC