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.