Art wrote:
"Can you comment on the tilt angle of the radiator to the ground to
achieve max horizontal polarization?"

Vertical radiators over the earth are optimally exactly vertical. Were
it not so, broadcasters would use tillted towers.

An excercise I`ve performed countless times is microwave path
establishment and optimization. I`ve bolted the tiny dipole feed into
the dish selecting horizontal polarization over vertical polarization in
most cases.

To establish a path, I set the azimuth using a transit and Coast and
Geodetic Survey maps to aim the dish on path. To aim for the horizon as
needed for a long path, I simply use a bubble level on the feed horn.

As soon as the signal appears, optimizarion begins by refining azimuth,
elevation, and polarization for maximum limiter current in the receiver.
Never have I seen any adjustment other than azimuth make any change in
the signal received. Parallel antennas at both ends of the path are
optimum. The same is true with vertical polarization for what is
essentially free-space propagation except for the grazing near the
middle of the path.

Tilt as Art implies it is a myth.

Best regards, Richard Harrison, KB5WZI