Topband: Ground Conductivity

[Rob Atkinson]

It is indeed true that variations in liquid soil moisture will
dramatically affect ground system performance and base fed vertical
impedance when an on, or below grade ground system is used.  Frozen
ground moisture is on a par with dry ground.  This is one of the
reasons for going beyond the point-of-diminishing-returns number of
radials--the more radials used, the more stable the feedpoint Z is,
over varying soil moisture in the radial field.   Antenna efficiency
is related to radiation resistance relative to the ground system.  If
you have a short vertical (inverted L) with a low resistance that you
cannot increase, you can improve it by lowering the ground resistance
by employing more radials.

73
Rob
K5UJ