Roy Lewallen wrote:
Attenuation through the ground depends on the soil conductivity and
dielectric constant, and the frequency. Here's the attenuation in dB/ft
for two ground types and a number of frequencies:

Freq MHz Avg soil(1) Vy good soil(2)
0.01 0.037 0.091
0.1 0.12 0.29
1 0.35 0.90
10 0.66 2.4
100 0.69 3.3
10,000 0.69 3.4

So if I get this right, a 2.4gHz signal in normal soil would be anttenuated
6.9 db (less than 2 "S units). In very good soil, it would be anttenuated
around 34 db, which would make it difficult to receive.

A Pringles can antenna has a gain of about 18db, that would certainly be
enough for average soil, and might be good enough for very good soil.

It also has the advantage of possibly being a 2 way link.

Geoff.
--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
New word I coined 12/13/09, "Sub-Wikipedia" adj, describing knowledge or
understanding, as in he has a sub-wikipedia understanding of the situation.
i.e possessing less facts or information than can be found in the Wikipedia.