320 AP losses signal strength

What would cause two APs to lose signal strength?, We have 4 ap’s in ABCD freq pattern.
-90 from under the tower.

A swap of frequency of the two opposite facing AP’s allowed us to read them at -55 again.

Strange…, Any help Cambium Team?

don’t messure under the tower,

the antennas spray pattern will flux outside azmoth.

backoff 200’ for every 100’ you went up assuming you used 2.5 degree down tilt,
this will not get you in beam width, but it will get you away from the odd shoots from the antennas.

the tower structure and the strange spray patterns will cause hot spots dirrectly under the antennas that will shift around with frequencies