[TowerTalk] HFT

[Jim Brown]

On 3/17/2021 1:19 PM, W7TMT - Patrick wrote:
> While it would be nice to get a small beam to the top of my mast 45’ above the saltwater, it isn’t practical nor safe. I have to put the antennas up on Friday morning and take them down on Monday. It’s only due to the kindness of my powerboat neighbors I can do that as my antennas occupy their airspace.


Hi Patrick,

I suggest that you study my work on the height of horizontal and 
vertical antennas.

http://k9yc.com/AntennaPlanning.pdf

When you're on sea water, you want vertical antennas with a feedpoint 
close to the water and a suitable plate that allows connection of the 
sea water to the rig as a very low impedance counterpoise. Antennas, 
horizontal or vertical, well above water level get very "lobey" in the 
vertical plane. Propagation of vertically polarized signals are strongly 
enhanced by the very low loss first reflection from the water in the far 
field, but this effect only works in directions where the first 
reflection is over sea water -- in other words, if you're at the dock 
without much water between you and land, you don't get that enhancement 
in directions that are over land.

73, Jim K9YC