Topband: Vertical on the Beach?

Michael Tope W4EF at dellroy.com
Mon Oct 25 01:51:13 EDT 2004


I have been scouting some beachfront locations with a mind to do
a portable operation on 160 meters and was wondering about
"reflection zone" issues for saltwater enhancement. One of the
locations I found which looks promising from a logistics standpoint
has a saltwater horizon that extends roughly 10 miles to the west
and north and perhaps 30 to 40 miles to the northwest. To the east
and northeast (critical for CONUS), however, it is only perhaps a
mile at most to landfall. Is this enough saltwater expanse to gain
saltwater enhancement at the low angles where it counts? For
example if I use 20 feet as a mean radiator height (I plan on using
some kind of top loaded vertical which will probably only be 40'
high), the "geometric" ray trace relfection point is about 1100 feet
from the antenna at a TOA of 1 deg, and at 5 degrees TOA its
only 230 feet from the antenna suggesting that I need to be careful
about getting too far from the shoreline with the antenna.  In any
case, I have a sneaking suspicion that ray tracing is way
oversimplying things and that my assumptions about mean radiator
height may be flawed. Any thoughts from the group on this subject?

Thanks& 73,

Mike, W4EF..........................................





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