Ground resistance measurements
160-meter Ground Connection Resistance at W8JI
Clay soil, dry conditions, 20-foot tall hat element resonant on 160 meters. All radials 50 ft long except for test radial, which is 1/4 wl electrical insulated counterpoise.
Performance Indications of Test
Ground systems are reactive. Poor grounds can add reactance. This is shown by the resonant frequency shift as the ground system is altered.
In slightly moist clay pastureland soil it takes about 8 short (1/8th wl) radials to stabilize the ground impedance.
In slightly moist clay pastureland soil, two or three rods make a poor RF ground for low impedance antennas.
If you use four short radials on a vertical, it is almost like no ground at all.
With small radial systems, ground rods can actually increase feed resistance. Use this particular phenomena with some caution, since I did not sweep frequency!