I've got a PTP800 link on the 11Ghz band at about 3 miles that has ben stable for the past 5 years.
Now the link is bouncing (link loss while it shifts QAM settings). Both ends were set to 256QAM.
Now, to get the link to stop bouncing I need to set one end to limit at 128QAM or the other link at 64QAM.
If I configure Unit A to 256QAM and Unit B to 128QAM, both units settle on 128QAM.
If I configure Unit A to 64QAM and Unit B to 256QAM, that is what I get.
If I configure Unit A to 128QAM and Unit B to 256QAM, It starts bouncing and is unuseable.
I suspect there is an issue with Unit B, but I have no idea where to look or how to resolve.