On Mon, 19 Jan 2004 19:06:06 GMT, Gary Schafer
wrote:
....
Here is a path loss calculator. It uses 20 miles as a default for the
range. You can put in some heights and note the amount of
path loss in DB that you get.
Then double the height of one of the antennas and note
that the path loss you get decreases by 6 db.

http://www.decibelproducts.com/Calculators/qegli.htm

Regards
Gary

This caculator gives the following caution:

"Note: The Egli model is based on data measured over radials mainly in
the eastern US seaboard and central plains states. It gives an overall
propagation loss over gently rolling terrain with average hill heights
of approximately 50 ft. "

You may have noticed that at sea, you hope to avoid regions with
gentle hillocks of 50 ft wave height. :-)

Brian W