Hi. I want to work 160, 80 and 40 with a 20 metre length of wire (fed into
an atu) that is to be supported between a mast and a pole on the house
chimney stack.

Here is a plan of my garden:

8.6 metres
_________________________________
\ x A |
\ |
\ | 5.8 metres
\ |
\ |
\_C________________________B_|

6.4 metres

x is where the antenna will connect to the atu.

distance from x to A is 7.8m
distance from x to B is 9.4m
distance from x to C is 5.4m

the angle at x, from points A and C is 73 degrees, so any ground wires
centered on point x would fan out 73 degrees..

Okay, what ground arrangements should I make? Do I drive in 2 or 3 2 metre
ground rods at point x and as many ground wires 6 inches below the surface
fanning out from point x, or what? Would I also connect a conterpoise wire
or wires to point x running a foot or so above ground?

Thanks for any advice.

Rich.

Richard wrote:
"I want to work 160, 80 and 40 with a 20 metre length of wire (fed into
an atu) that is to be supported by a mast and a pole on the house
chimney stack."

The wire to earth from your atu is a part of your antenna even if you
don`t ground its far end. If you desire a strong vertical component to
your radiation, put as many radials in your garden as possible to
minimize the distance displacement current flows to reach a copper earth
return wire.

Best regards, Richard Harrison, KB5WZI