Hi, i think your signal is too high at each end , swamping the input of the radios , turn the tx-power way down and check the signal and throughput again.
mmmm i think the same, but look this.
in the AP ear the CPE with -0 dBm, and in the CPE ear the AP with -25 dBm,
look this, in the CPE he no associate with the AP, is less power, example if -40 dBm, the link will loss, and can not associate, ???
in the AP work in 26 dBm, in the CPe with 17.5 dBm, i can put more low the CPE , but the AP is tranzeo, and no have control of power.
this link of 3 kms, have a little problem, because have a obstacle
AP --- 200 mts obstacle------2.8 kms the CPE
in the CPE when make the site survey always see the SSID, but no make associate , need go to -25 dBm or more power.
in the AP, is hard to make the association, in the first time, make the link in the roof make the link two times, and with -0 dBm, but the ping of 10 only reply 3.
now put a tower go up to 12 mts, the AP see the same -0 dBm, but no loss ping, 100% always reply the ping perfect.
work in channel 1 in 2.4 Ghz, and the AP tranzeo, no give the speed status, change to channel 11, and see in the link status 1 mbps .
mmm only in the area have other AP, and this is in channel 6.
????, i am thinking need another 24 dBi sector grid, this link make easy with 19 dBi and in the CPE 13 dBi antenna, no need more gain, and the power in ap 26 dBm, is too much, and the cpe 17.5 dBm.
but, have a this obstacle , maybe work better in vertical polarization, or put other antenna change in the AP 19 dBi, and put 24 dBi
IMPORTANT when test the speed, in the CPE the download is better is 500 kbps, when upload to AP from CPE, the speed is 200 kbps or less.
this happend, only if one alignament of antenna is bad, but the obstacle is there, i am thinking change the antenna of 19 dBi to 24 dBi, and see what appends