Ground system

Most of my experiments are with antennas end fed against ground in my back garden. The ground system is vitally important to antenna efficiency. Having read all the usual texts I have incorporated:

  • 20 random length copper radials cut to fit the spaces available slit into the grass.
  • 4 copper/steel earth rods around the base of the automatic ATU, together with some 6 square metres of earth mat made of galvanised steel chicken wire.
  • The above are connected to the ATU with a copper strap some 70sq mm in section, made up from paralled household power cables. This is about 1.5m long.
  • Single counterpoise for all bands 160m to 15m and double counterpoises for 12m and 10m connected direct to the ATU and running in bushes along a fence about 1m high.

A professional gas-filled lightning arrester is fitted at the connection for the co-ax feed to the house, with a short strap to the ATU ground cable. Static charges are bled away with a small wax impregnated RF choke directly across the co-ax connector.

Any RF on the co-ax braid due to antenna imbalance or direct pick-up is stripped off by a professional external grade choke just before the ATU connector plus a 10m length of buried feeder nearer the house. I also use a coil of co-ax feeder just after it enters the house. I have no measurable “RF in the shack”

Although not optimum this system seems to produce quite good results.