[TowerTalk] W7PUA Tiny Ground Probe

[Brian Beezley]

K9YC said:

"But it does show trends that can help us think about the viability of 
vertical antennas..."

The FCC conductivity map indicates a conductivity of 4 mS/m for N6LF's 
QTH in Oregon. In January Rudy measured 22 mS/m at 1 MHz in his field. 
The map indicates 15 mS/m for AE5CZ's QTH in New Mexico. Larry measured 
0.45 mS/m at 1 MHz in a sandy wash near his home.

Because of gross discrepancies like these, I think both the FCC map and 
the ARRL ground constants are worthless.

If you don't want to measure your own ground, I think the best 
alternative is to use the Hagn generic ground constants. I have no way 
to verify their accuracy, but they were devised by a professional who 
performed ground measurements worldwide for years. This writeup shows 
graphs and tables of the Hagn values, extrapolations to LF/MF/VHF, and 
provides a link to Hagn's paper that describes the theory and 
measurements underlying everything:

https://k6sti.neocities.org/hfgc

Brian