"Jim Lux" wrote in message ...
By the way, a Yeasu technician once recommended salting ground
rods to resolve a poor grounding situation at the time, so I've
been doing that ever since (can't hurt), especially during the
dry summer months. Adding water is pretty obvious, so didn't
think I needed to spell that out, Dave.

Hmm. and that Yaesu technician has what training and experience
in grounding systems for lightning protection (other than what's
printed in the front of the manuals)?

And did the salting improve anything? if so, what? adding
grounding is almost always the wrong solution to operational
problems (RFI, for instance), since the purpose of grounding
systems is to deal with abnormal events (short circuits,
transients, etc.).


I will have to second Jim's statements here. Anyone that thinks that salting ground rods will provide a better radio frequency ground is fooling himself. Charged ions in water move at relatively slow speeds that are determined by, among other things, the temperature, the size of the ions, and the viscosity of the solution. At low frequencies, the period of the AC voltage allows the ions to migrate a considerable distance. But at higher frequencies, the period becomes shorter and the ions can move only slight distances before the polarity, and hence the direction of the ion migration, changes. The conductivity of the solution follows a reciprocal relationship with frequency.

By the time we get to radio frequencies, the dissolved salts do little to increase the ground conductivity. What is important, however, is the moisture content. This is why moisture retaining clays such as bentonite are sometimes used.

In areas where the ground is frozen. it is difficult to get a good radio frequency ground. This is because the dielectric constant of ice is low while that of water is high. In this special case, adding salt might help as it lowers the freezing point of water.

At the WYFF transmitter site on Caesar's Head, SC, there is an 800 foot tower atop a 3100 foot granite mountain. To get a decent ground for lightning protection, they ran three 1/4" thick copper sheets about a foot wide out from the base of the tower to where the guy wires attached. This provides an effective capacitive grounding system as the granite itself is not very conductive. They get hit by lightning frequently. Previous station engineers have related many stories about ball lightning rolling around the floor in the transmitter room.

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73, Dr. Barry L. Ornitz WA4VZQ