[TowerTalk] Radials over salt water?

[Maurizio Panicara]

> >> The point of question is: does the salt water ground (close to perfect)
> >> reduce the losses in return currents to the point where few radials are
> >> sufficient?
>
> That certainly was the conclusion at 6Y2A et seq.  If I remember
correctly,
> they used only one or two radials over sea beach, largely to even out
tidal
> variations in feedpoint behavior, but the low-angle performance is
> phenomenal.
>
> 73, Pete N4ZR
> Contesting is!

An high overall antenna efficiency is not necessarily coincident with a big
GP efficiency at very low elevations.
If the important point is to radiate at very low angles (below 1 degree) the
GP antenna has to be maximally efficient for that purpose.
Elevating a vertical radiator with counterpoise over ground increases the
value of  the pseudo brewster angle. This means that
below such angle a phase shift occurs and the GP and its image are out of
phase and a signal cancellation (decrease) occurs, independently by what's
the overall antenna efficiency.
The easiest solution when close to sea and to obtain < 1° elevations seems
to be that to keep the antenna feed point close to the ground and using a
balanced counterpoise made tilting up a bit two quarter wave radials.

73,
Mauri I4JMY







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