Rudy Severns, N6LF, has updated his writeup on ground parameter measurement with several new probe designs. A ground probe and NanoVNA let you measure the permittivity and conductivity of your local
Rick, see Rudy's original writeup where he goes into this in great detail. His recent update is just an update on that earlier work. He doesn't repeat the basics. It only gives a spot measurement of
Thanks for the reference, Paul. I located it here: https://nvlpubs.nist.gov/nistpubs/Legacy/TN/nbstechnicalnote139.pdf Brian _______________________________________________ _________________________
Good guess, Jim. N6LF just sent me an old IRE article from 1954 that explains the derivation of the map. It's intended to predict propagation for AM broadcast signals over broad areas, not accurately
https://www.antennasbyn6lf.com/ The reference I gave to his original soil parameter article was actually to a preliminary version. Here's the final article: https://rudys.typepad.com/files/qex-nov-de
Ground permittivity and conductivity are needed to model an antenna over ground. Accurate values are particularly important for vertical antennas and for horizontal antennas with low conductors. You
"Brian, can you comment on how your table values relate to the frequency adjusted ground characteristics shown by EZNEC?" Dan, I've never used EZNEC and know nothing about it. The ground parameters a
I've updated my writeup on HF ground parameters. I revised the extrapolation of 1 MHz FCC data to the HF ham bands. I also added data for seawater and freshwater, both of which vary considerably with
To better represent specific terrain, my HF Ground Constants page now includes an interpolator for the Hagn generic curves. The Hagn HF values are more realistic than the ARRL ground constants offere
conductivity is poor. That's a good use of the FCC map, Jim. I had completely written it off for ham use once I discovered that it applies only to the AM broadcast band. Values will be quite differen
Try this: http://ham-radio.com/k6sti/FCCMapArticle.pdf Brian _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contestin
There's a problem with using the FCC conductivity map to rank HF conductivities that I overlooked: skin depth is much smaller at HF. Soil with different conductivity may come into play at broadcast f
The bobtail virtually eliminates loss due to feedpoint ground current. And it minimizes ground current loss near the antenna since high wire currents are well away from ground. But it can't escape th