GeneralG9B06
Where should the radial wires of a ground-mounted vertical antenna system be placed?
C
Answer
Antennas and feed lines
Type
A
As high as possible above the ground
B
Parallel to the antenna element
C
On the surface or buried a few inches below the ground
D
At the center of the antenna
Answer Notes
Radial wires act as the missing half of a ground-mounted quarter-wave vertical antenna, creating a path for return currents. For these ground-mounted systems, the radials should be laid flat on the ground surface or buried just a few inches deep.
Burying them slightly helps protect the wires from tripping hazards, lawnmowers, and weather without degrading their electrical performance. The earth itself forms part of the antenna's near-field environment, and keeping the wires close to the surface ensures maximum coupling.
Placing them high above the ground applies only to elevated ground-plane antennas, not ground-mounted ones. Running them parallel to the antenna would ruin the required perpendicular ground plane, and placing them just at the center ignores the need to spread them outward to collect return currents.
Previous · G9B05
How does antenna height affect the azimuthal radiation pattern of a horizontal dipole HF antenna at elevation angles higher than about 45 degrees?
Next · G9B07
How does the feed point impedance of a horizontal 1/2 wave dipole antenna change as the antenna height is reduced to 1/10 wavelength above ground?