"Ruben Undheim" wrote

I have my shack on the second floor, about 8 meters above ground. I am
going
to use a dipole antenna for 20M
Should I use the water pipe system as ground, or should I use a thick wire
on the housewall down to a ground rod?
I fear that the wire down to the ground rod may emit unwanted RF (have
read
that somewhere).

Hi Ruben, sounds like three stories above ground, two stories would be 4
meters even if a 1 meter+ raised foundation was included. At any rate, a
dipole is a complete antenna that does not use an RF ground or counterpoise.
Transceiver mismatches will place high SWR on the feedline, not an RF ground
should you install one anyway. If you later add some kind of longwire or
other voltage-fed antenna then an RF ground would be important. You could
use 12" wide 20 ga copper flashing (available at roofing companies) to make
a workable ground from your elevated shack location. Anything less would
have incredibly high impedance due to the distance to earth ground. Your
dipole antenna feedline should enter the building at ground level, and the
coax shield should be grounded there before coming "up" into the shack.
There will remain a high potential between your shack equipment and the
earth ground no matter what kind of ground you attempt at that height. The
12" wide copper strap connection would just be the lowest potential you
could achieve, water piping or any solid wire size would not even come
close.

Best regards,

Jack Painter
Virginia Beach VA