> >If you look at Hagn's actual measured data you'll see
over
> >30 mS or 50 mS/m soil (very good earth) FS drops several
dB
> >as antenna heights move below .05 wl.
> >
> >.05 wl would be about six feet on 40 meters and about a
> >dozen feet on 80 meters.
>
> Perhaps. I did say it was a quick model. I suspect that
the better the
> ground, the more pronounced the effect.
Not "perhaps", that's exactly how it is over wide variations
in soil.
Over Georgia clay in my pastures the earth losses just suck
the signal away from a low dipole. In rocky Conyers soil it
did the same. In Ohio's sandy black wet loam the same, and
in Thailand's thick highly conductive dirt it did the same.
It won't be good even over saltwater with the antenna very
low.
If you had near zero loss, say a large copper mat or grid,
the soil losses would be nearly zero but then conductor
resistance in the antenna would kill efficiency.
The only "electrical thing" gained when an antenna is
installed below about 1/8th wl is you rapidly add losses to
the system. You add an attenuator pad.
If the model doesn't show that over normal ranges of
conductivity the model is out of sync with the real world,
and it has nothing to do with matching losses.
73 Tom
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