Fig. 1. (a) The vertical electric field at 200 m calculated over finitely
conducting ground of conductivity 0.002 s/m and relative dielectric constant
five by replacing the attenuation function in equations by the attenuation
function corresponding to a dipole at ground level is shown by a dashed
line. The vertical electric field at 200 m calculated without making this
approximation is shown by a solid line. (b) Variation of the ratio of the
horizontal field at line height calculated by using the approximation III to the
exact horizontal field at line height: D = 200 m, ! = 106 rad/s, = 0:01
S/m, " = 5; D = 200 m, ! = 106 rad/s, = 0:001 S/m, " = 5; D = 200
m, ! = 107 rad/s, = 0:01 S/m, " = 5; D = 200 m, ! = 107 rad/s,
= 0:001 S/m, " = 5. D is the horizontal distance between the dipole and
point of observation