Customer wants to have a monopole bulit to hold ptp650 integrated.

Wants me to give him a spec for the monopole

Don't know where to start. I am sure their is arithmetic around somewhere to caculate maximum sway of pole as a funtion of antenna beamwidth and distance, but I can't find it and link planeer doesn't seem to say anyhting about it.

The question makes perfect sense. Look at the horizontal and vertical patterns of the antenna to figure out how much sway it would take to get the antenna to the -3db point. With an integrated patch antenna you will have a fairly wide beamwidth compared to a higher gain dish, so a few degrees of sway aren't going to do anything.

If the pole is swaying more than 5~10 degrees in any direction you might have other problems. How high does the monopole need to be?

We have a 1 dB loss of gain (green line) at -2 and +3 degrees. As Jacob says, no monopole should have twist and sway greater than this. We have a 3 dB loss of gain (red line) at -4 and +5 degrees.

It's interesting to note how steep the pattern is a few degrees from boresight. If the antenna is not perfectly aligned to start with, movement of the tower has a bigger-than-expected effect.

If you have a larger antenna with narrower beam, the twist and sway requirements will be considerably more demanding.