"Dave Platt" wrote in message
...
In article ,
Rob Collis wrote:

Hi Joe,
IMHO it is best to isolate the ground used in the shack from the household
ground. This should reduce noise from any mains supplied appliances. You
could use a third rod for the antenna no problem.

In the United States, most localities incorporate the National
Electric Code into their own local building codes. It is my
understanding that the NEC requires that each building structure have
precisely one "ground system", and that this requires that all ground
rods be reliably "bonded" together (typically via 6-gauge-or-heavier
wire).

The ground-system bonding is required in order to reduce the degree to
which ground-voltage differentials can occur in the case of an
electrical fault or nearby lighting strike. The bonding reduces the
current that can flow through appliances that are connected to two or
more independent "ground" systems (e.g. a building's main electrical
ground, and a separate ground stake near an antenna).

Putting in a second ground rod near the hamshack can be a good idea,
as it reduces the length of the ground wire from rig to ground rod and
can improve the quality of the RF ground (depends a lot on wire length
and frequency). However, in order to comply with the NEC, this ground
rod must be bonded to the main building ground.

I don't know what the rules are in other countries.

--
Dave Platt, AE6EO

Dave is correct about NEC requires, HOWEVER please check with you local
municipal (or country/parish) building department (or code enforcement) -
there are variations that are more restrictive than NEC in SOME U.S.
localities.

That said, IF you are going to have a tower or large antenna array - RF
grounding needs to be addressed separately from electrical service
grounding. This area also has different requirements in SOME areas (for
example - parts of Florida have the highest lightning hits per year). Glen
Zook, K9STH has given talks and presentations on this subject - this
information can be found he
http://home.comcast.net/~k9sth/

w9gb