Floyd Davidson wrote:
"And darned if a few years later a build up of rhime ice on the 43 feet
of tower above the dish didn`t fall down and bend that dish into a pile
of rubble too,"

By Floyd`s logic the lesson must be that a dish must always top the
tower, out of harms way.

The antenna does not have to receive zero interference, though that
would be nice. We are always susceptible to some interference from
somewhere at some time. Multiphop systems often must reuse just a few
frequency pairs over and over. It`s all the regulators will allow.
Situations arise when anomalous propagation provides strong signals at
extraordinary distances.

Planning includes avoiding azimuths which would repeat to present
interference at a great distance along with a repetition of a frequency
which might interfere. A solution to interference is coordination.
Another is often high performance dishes which do a better job of
rejection. I`ve used the shielded variety from Antennas For
Communications (AFC) with good success.

Ice may be falling, but the sky isn`t in the case of microwave
interference.

Best regards, Richard Harrison, KB5WZI