>
> How can you measure the resistance (?) of a cable running to earth? If
I
> wanted to check if a cable already providing an electrical earth
> connection
> was working to optimum how could I do it without breaking the bank for
> test
> equip? Is there a difference in any results obtained for RF &
Electrical
> earths?
>
First, there is no such thing as an rf ground. (time to put on the
asbestos underware!) Any RF you generate is looking for a path back to
where it came from. The most you can hope to do is provide as low an
impedance path as possible between components to keep rf potential
differences in the shack to a minimum.
As a corollary to the above, there is no such thing as a lightning
ground. Again, the aim is to keep the potential differences between
equipment as low as possible. The hardest part of this is usually
reducing the potential difference between power cables and 'grounded'
equipment... but that is a whole different thread.
As for testing your electrical safety ground the best thing is to have a
qualified electrician or your electric company test it for you. It
takes a special meter and measurement methods to do it properly. They
can also check your installation for you to be sure that all grounds are
properly connected to each other, that all applicable codes are being
followed, etc. In some areas electric companies may also be able to
install service entrance lightning arresters either free or cheap.
David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
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