On 7 sep, 16:22, Roy Lewallen wrote:
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

Hello Roy

I do not saw this post. I do not know how you make the simulation, I
try a similar one changing "Wire Loss" to "User defined" an put there
5 ohm-m.

The "Average gain" results was very bad, as yours, then, thinking of
aspect ratio of IEEE antenna paper (and big masses involved in water
and soil reflections) I modeled it with 300 mm diameter wire. New
Average Gain now was 0.53 = -2.65 dB, pretty near values given in
paper.

Ita was approximateli correct my procedure on EzNEC? what do you think
about results?

Thank you very much in advance.

Miguel LU6ETJ

PD: I will repeat this post in another point of thread becaus this one
it is older.