RSSI chain imbalance on multiple SMs

The reason for crossing the pigtails on UBNT antennas was due to direction of the rf elements in respect to polarity of the propagated wave. This polarity does matter as you do not want your received wave to be out of phase with the receiving antenna. Most high quality antenna manufacturers follow the same standards which are reversed of WIFI which UBNT follows.

With mimo, the link is created with one radio chain and each end will determine the best radio antenna pair to receive the signal (notice not transmit). Basically the two most in phase with each other. The second chain is on the remaining radio antennas which may not be anywhere near the same phase and still make a low quality link.
Keep in mind that this is completely different from OFDM-MiMo which truly does not care and uses all radios and antennas at the same time on all chains.

Personally I would like to see the epmp line use 5mhz ofdm chains and we select the center frequency and number of chains ( width) with higher modulation schemes that are determined by the 5mhz single chain. More bps/mhz is always good.

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Thank you to everyone’s comments/advice on this thread. So I have not climbed yet to try the RP pigtails but I did open a ticket with Cambium and explained my situation of a 10db chain mismatch on all of my 6 SMs that are attached to the AP. So they said it could very well be the cables between radio and sector antenna so they suggested that I try the AP in ptp mode and then I can see the ealign on the AP side to the one SM that would connect. The chains for the SM on the ealign on the AP were perfect -63 and -63… put it back to ptmp mode and logged into the same SM and the chains had a 10 db mismatch. Cambium said they are looking into it.

@Douglas_Generous @ninedd @brubble1

So we climbed the tower, disconnected and reconnect the 4 RP cables and issue went away… so @Douglas_Generous was correct! When I swapped the radios on my first climb one or more must not of been seated correctly. I thank all for their help/advice! This a great community!!