[BC] Grounding by the sea

[Richard Fry]

>Could the tower/signal ground be capacitively coupled to the variable 
>height water level found in tidewater stations?
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If one plate of such a capacitor is installed at a fixed location above 
high-tide sea level w.r.t. the tower base, then its capacitance to an 
adjacent plate consisting of sea water will vary as sea level ebbs and flows 
with the tide.  That will vary the resistance of the connection of that 
radiator system to r-f ground, and hence the base Z and radiation efficiency 
of the antenna system.

If there is an economic and FCC choice, maybe better to find a location for 
the radiator a bit inland, where a set of 120 x 1/4-wave buried radials can 
by installed and used as the r-f ground.

Such an installation can produce more stable groundwave signals over the 
land areas that are most important to an AM broadcast station, and with 
little sacrifice of field intensity compared to a monopole using even a 
perfect r-f ground (as implied by the 1937 Brown, Lewis & Epstein 
experiments).

RF