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Old May 30th 06, 02:25 AM posted to rec.radio.amateur.antenna
chuck
 
Posts: n/a
Default Yacht Rf ground and radials

Jon Kåre Hellan wrote:
Roy Lewallen writes:

bob wrote:
I dont have NEC4 is it too much to ask you to run the
model. Radials over sea water versus a direct connection?

Sure. How many, how high, and how long? The foot-long wire produces
efficiency of virtually unmeasurably close to 100%. So radials can't
be significantly better. What sort of efficiency are you expecting
from the radials?


How does a copper wire behave when submerged in salt water? Won't it corrode
rapidly, so that you don't get a metal to salt water connection, but
a capacitive coupling across copper oxide?

Not a rhetorical question, btw. I really don't know the answer.

73
LA4RT Jon


The copper alloys widely used in wires are quite resistant to corrosion.
Even when immersed in pure seawater, their corrosion rate there is on
the order of 0.025 mm/year. Unfortunately polluted waters can increase
that rate.

The metal to water interface may indeed be affected by the corrosion
layer. This problem is frequently seen by electricians when installing
grounding rods in the earth. However, I imagine the capacitance in this
case would provide sufficient coupling at RF so that it would not be a
problem. Biofouling might be of greater concern if corrosion does not
occur fast enough.

73,
Chuck
NT3G

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