In a message dated 97-09-14 11:51:41 EDT, w2up@itw.com writes:
> I am planning on adding (or replacing) some ground rods to my tower
> ground. The present rods have been in about 8 years. Should I
> assume these are corroded, leave them as is, and just add additional
> rods/connections as if they don't exist?
You're probably correct to assume that they "don't exist". If they just
had a mechanical connection (ground wire to ground rod) of some sort, it
probably has a high impedance due to oxidation/corrosion over the years. The
only way to insure a longterm low resistance connection is to use an
exothermic method like Cadweld.
Digging up the existing ones (but not removing them) and refurbing them
probably isn't worth the effort.
>Would there be any harm in
> leaving the old rods connected, such as oversaturating an area of
> ground in case of a hit?
I would leave them as is and install some new ones. It's almost
impossible to "oversaturate" a ground system. Each bit of ground wire and
additional ground rod increases the efficiency of the ground system by
lowering the system resistance (I'm ignoring diminishing returns and cost). I
would refurb the current ground system connections that you can reach that
are probably above the ground (earth).
If you took any ground system measurements in the past, you can do them
again and compare the results. A simple method is described in the ARRL
Handbook.
73, Steve K7LXC
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