[Elecraft] Low antennas in high places

[Stuart Rohre]

No matter what the ground conductivity is at a given hill top located 
antenna, what is shown in one ARRL Antenna Compendium piece on gains from an 
antenna near the edge of, and atop a hill, is that you are no longer 
shadowing say, a dipole parallel to the cliff face from radiating at angles 
below zero degrees.  (Zero being parallel to the horizon, and any angle 
below horizon being called negative for this discussion.)

This signal, which is usually absorbed by nearby earth in the near field for 
conventional dipoles on flat ground, may have enough space to radiate quite 
a ways at a low or negative angle, then it might reflect in the Fresnel 
zone, (far field), or even just a few wavelengths from the hill.   In any 
case, by the laws of wave reflection, angle of incidence equals angle of 
reflection, and thus the ground reflection will head for the ionosphere at a 
very favorable for DX, low angle of take off.  Thus, the advantage of a 
horizontal antenna near the cliff edge on top of a hill.

Stuart
K5KVH