Optimal Antenna Elevation angle
What is the best elevation angle to set an antenna at for LOS receiption? I am pretty much in the highest spot in the immediate relatively flat neigbourhood and I have currently set my antenna to point pretty much horizontal. I know that if there is some obstruction nearby then one should aim for the top of this obstruction as the adjusted horison. However, as in my case, would there be a significant amount of receiption coming in at above zero elevation angles due to atmosperic "bending" of the electro magnetic propagation? I can imagine that for long distances this may be more important but what about the LOS case where the transmitting tower is about 20miles away?