[BC] Grounding by the sea

[Alan Alsobrook]

Jeff Bottalico wrote:
> I don't know the station in Monterey but the KGU, KHNR, KHCM tower is
> interesting.  It has galvinized pipes going into the ground and the
> salt water table is only 1.8 meters below ground.  Here is the KHCM
> app.  Nice diagram about 17 pages in.

Having a few towers that are grounded by sea, (5000mS conductivity) 
there are problems with it. Pretty much anywhere you have salt water, 
you also have tides. Your base Z goes up and down about twice a day.
Also while the signal will seemingly go forever over the water, it can 
die hard and fast going on land if it doesn't have proper radial support 
in that direction. Seems to me most of the listeners will likely be in 
that direction.

Also you have to couple to the salt water, this again is not easy since 
most anything conductive you put into it will be corroded away in a 
short period of time. I would not expect galvanized pipe to last more 
than a couple years.  Copper seems to last the longest, but even it will 
degrade over time.

Bare copper radials degrade in a very interesting way, the outer surface 
oxidizes, and over time it turns into a enlarged brittle green tube. If 
you pick it up it will crack open reveling the remains of the radial 
wire. Which is nice bright shinny copper strand about the size of 30ga 
wire.

-- 
Alan Alsobrook CSRE AMD CBNT
St. Augustine Fl. 32086 904-829-8885
aalso at Bellsouth.net