Center-Loaded 8' Mobile Whip
Ground Mounted
7.255 MHz
1 wire, inches
10  0 0 0  0 0 96  .125
1 source
1,100,0
1 load
inductive
6,6,1900

Use this model to investigate the behavior of mobile whips over various types
of earth.  Nearby ground losses will not be reflected in the input impedance or
whip current, so the indicated gains will be too high, but you will be able to
see the effect of ground quality on the radiated patterns.  The 6 ohms in the
load represents a Q of about 300 for the coil.  Estimated local ground loss
resistance should be added into the feedpoint as well.  The resonant frequency
(and even efficiency) vary with the whip diameter.  For more information, see
the paper "Optimum Design of Short Coil-Loaded High-Frequency Mobile Antennas"
in the ARRL Antenna Compendium, Vol. 1.