Odd GPS scenario. Let me start with we have already had a ticket with Cambium and they have recommended replacement of the 450i AP. We are limping along at this time due to site access issues, so looking for input and suggestions as to what could be the issue as I’m not convinced this is a bad AP.
Site consists of 3 450M and 2 450i APs. These are powered via a CMM5. We have the controller unit connected to the network switch and then 2 56V injectors daisy chained off of that. Injector #1 has 2 450M and 1 450i and injector #2 has 1 450M and 1 450i. Injector #1 has the GPS unit plugged into it providing sync to the entire site. We do have other sites with this 450M/450i mix with the same type of CMM5 setup that are not experiencing any issues.
Issue: At time of ticket to Cambium we only noticed with one AP, but BOTH the 450i APs will drop sync down into the 50-60% range at random times, though typically not the same time, resulting in re-registrations from SMs and general issues with customer service. Then it will bounce back up to a 90-100% range and rock along just fine.
It was not noticed until we bumped our firmware up to 16.2.3. We lowered firmware on 1 of the 450i’s to 16.2.2 with no change.
We do not notice the sync pulse status changing on any of the 450M APs. To me this rules out an issue with the CMM (APs split between 2 injectors) and the GPS. One question is, are the 450M APs maybe not as sensitive to GPS sync pulse as the 450i APs?
I’m hesitant to say it is the 450i because it is happening to both units. Granted these were installed at roughly the same time, so could be the same batch with potentially same hardware issue, but at time of install no issues were noted.
We do have other 450i APs deployed by themselves with no injector involved and I have noticed some fluctuations in the GPS sync, but typically no lower then 80% and again, not consistent.
The CMM5 is eligible for a firmware upgrade, but again with the 450M APs not experiencing an issue I’m hesitant to point a finger here. I do plan on upgrading the firmware once we have ability to access the site in case something blows up, but what would an upgrade hope to resolve?
Via the CMM5 we have toggled power and GPS for the 450i units with no change in behavior.