Hello Stefan,

> What is the distance between the earth rods? And what is their length? 
> What is the distance to the shack/house/noisy earth?

The first earth-point is the tower base. 
It's a concrete base, abut 1m square, about 2m deep, at about the bottom of
the hole,
10 rods (0.9m long) are driven rather radially, before the concrete was
poured.
16 ohm, at AF (820Hz) ground resistance meter.

The second earth-point is copper mesh, 0.3m wide mesh was U-shaped, 15m
long,
buried about 0.1m-0.3m deep along the base of my house. 10ohm/AF.
The closest distance to the tower is about 1m, the farthest about 7m.

As the second earth-point, I tried another mesh, also 0.3m wide, 15m long,
0.1m-0.3m deep, 
along another edge of the base of my house,
at about 8-10m away from the tower, 12.5ohm/AF,
with no difference noted (for me).

The last earth-point is beneath the shack, a 1m square copper plate, buried
at 0.5-1.5m
at about 8m away from the tower.
The shack is on the ground floor.

  I noted errors of earth resistance values in my previous mail. Sorry.


> Can you measure the coupling capacity between the shack ground and the RF
ground 
> (coax disconnected between the earths) using a 137 kHz sine voltage?
I guess the impedance between the two ground terminals would be resistive,
rather than capacitive.
Well, I think I can do it, but at 100kHz, using a handy LCR meter
U1733C/Agilent,
which is now at my friend's house, and I have to get it back.
So not now....

73s, Hideho YAMAMURA/JF1DMQ