Richard Fry wrote:
"Such service (VHF and above) is produced by radiation from the transmit
antenna typically at elevation angles from zero to several degrees BELOW
the horizontal plane."

A broadcaster doesn`t want to skip over his station`s nearby customers.
His distant customers likely receive the station from a grazing
incidence due to earth curvature.

I initially set dishfeeds on point to point microwave systems with a
carpenter`s level for the right elevation angle. I seldom was able to
improve the signal using on-the-air adjustment of antenna vertical
elevations.

In Scotland a few weeks ago I noticed the Satellite dishes aimed at
birds parked over the equator. Scotland is so far north that the
dishfeeds seemed horizontal. I saw some that dipped below the
horizontal. I doubt those were adjusted for best results. The beamwidth
is probably enough to get a picture anyway.

The point to point paths we designed had enough clearance to allow
anomalous atmospheres making the earth appear half again its actual
size. To that grazing point clearance, we added 0.6 1st Fresnel zone
clearance.,

Then we produced paths with 40 dB fade margins and limited the paths to
22 miles. Where we could, we produced redundant paths through looped
systems or space diversity.

High fade margins help when there are no fades by suppressing system
noise, a must in long systems with many hops.

Best regards, Richard Harrison, KB5WZI