On 9/6/2010 5:06 PM, Frank wrote:

On 7 MHz a dipole constructed of salt water: Er = 81,
conductivity 5 S/m, and 0.5" diameter has a free
space efficiency of 0.08%. i.e. with 100 W input
the total radiated power = 80 mW.

Frank
(VE6CB)

That looked so bad I had to run an analysis to see for myself. Sure
enough, it's that bad. And even with a 0.25 inch diameter column at 146
MHz, the efficiency is only on the order of 1%. A foot and a half of
wire vs. a pump, power source, and ferrite transformer? No contest.

Roy Lewallen, W7EL