On 3 Nov 2004 13:16:53 +0200, "Ruben Undheim"
wrote:
Should I use the water pipe system as ground, or should I use a thick wire
on the housewall down to a ground rod?

Hi Ruben,

The water pipe is better, a ground rod is OK. For a balanced system,
ground's only use is for AC safety (to protect YOU).

I fear that the wire down to the ground rod may emit unwanted RF (have read
that somewhere).

As you are using a dipole, this unwanted radiation will occur only if
it is unbalanced. The radiation comes from "Common Mode" current.
"Common Mode" current is the difference in the two currents in each
half of the system that is unbalanced. Dipoles are balanced designs,
but not always balanced installations.

How can you tell when you have an unbalanced system? This is not
easy, OR if it is easy, it is a real problem.

One SWR reading does NOT indicate an unbalanced system. One SWR
reading does NOT indicate a balanced system.

The most obvious sign of "Common Mode" current occurs when your
transmitter acts odd by being difficult to tune, folding back its
power, or you can actually feel the sensation of current on bare metal
(like connector shells or a chassis). A minor sign of "Common Mode"
current is receiving signals on your dipole that should be in its
null. This last sign may even be a preferred condition, thus subtler
signs may go unnoticed.

What this means is that "Common Mode," or system unbalance, or ground
wire radiation may not be a problem even if it exists.

73's
Richard Clark, KB7QHC