Topband: RF earth ground instability
Bruce
k1fz at myfairpoint.net
Thu Feb 4 12:48:20 PST 2010
In Broadcasting, a large number (120 in U.S.) of radials are required since
the 1930's. This gives seasonal frequency, current, (array phase), stability
to vertical polarized antennas.
The problem appears to come from articles written about the diminishing
returns of more radials. These articles should also give information about
instability probabilities in changing climates and ground water conditions.
73
Bruce
<snip
"...We see this effect in the Arctic every winter. It is not the leaves but
> the ground.
> Once I increased the radials to (A Lot) the vertical antenna stayed put at
> 1832 or so. I actually made this measurement every week for a few years
> and
> could watch the freq shift up as the winter came and back down as spring
> stated to thaw the ground. I finally ended up with 150 radials to stop the
> effect...."
>snip
*********************************
>snip
There's definitely a connection here, with what you say: my radial field
(per each "L") consists of just 24 insulated radial wires, 1/8-wave long,
placed atop the ground---a FAR cry from your 150 radials there.
>snip
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