4.6 - Shedding all stations, GPS issues, and Smart Antenna disconnects

I upgraded 3 of 4 3k APs at one of my sites to 4.6 the day after it was released or so and it has been a bumpy road ever since.

The primary issue has been GPS sync - Whatever fixes were in the 4.6 branch for sync don’t seem to apply to my situation. Of the 3 APs (2 3000 and 1 3000L), all lose sync at random times, for minutes to many hours. All 3 have the holdoff timer set to 864000 and occasionally exceed that timer and stop transmitting. Typically sync magically comes back a few moments after TX stops. This same issue has been present on all 3k firmware to varying degrees. It was also present on one of the APs when they were all 1k.

The secondary issue is two of the APs shedding all stations for reasons unrelated to sync loss. This started happening around the same time on both APs but doesn’t happen simultaneously on them. This has not happened on the other 2 3k APs at this site. This does not appear to be noise related, SNR and MCS rates don’t fluctuate drastically, the stations just all get shed and then come right back. This is new behavior since the upgrade to 4.6.

The third and least critical issue are alerts about the BSA being powered off and back on again. I’m unsure if this is really happening, or if it is false reporting by the APs. This happens on one of the AP a few times per day and the other once or twice per week.

I have open tickets for items 1 and 2, but nothing has come of them yet. Putting this out there to get any other feedback.

Thanks for high lighting this Jake. We will give it some urgency. Btw, did you ever replace any of those pucks at any point? I can’t remember.


Hi Sakid,

The pucks on the 3000 APs with BSA are the square ones that were shipped with the MU-MIMO sector (or the radio, I don’t remember). The pucks on the 3000L are the old round ones, so they have not been replaced by the newer square units.

I do not recommend updating anything to 4.6 presents details better to stay with 4.5.6


Have you experienced any of the issues I’ve mentioned? If so, providing details would be helpful to everyone involved. Otherwise, just stating “stay with 4.5.6” isn’t very productive.


We are checking the mentioned issues in the lab right now and Cambium Support Team will contact you ASAP.
Meanwhile, I would like to update everyone, that has been already released with 3 major defects fixed.

Thank you.

@Fedor I appreciate you checking in the lab, you also have access to my network and these radios if needed. None of the mentioned issues are addressed in so far as I can see.

Right. I just highlighted that if anyone would be interested to try the new FW it makes sense to take, not 4.6.

Thank you.

We dont use pucks anymore and seems to work fine without them…

Sakid were having a few small issues with aps dropping everyone on 4.6 since upgrading. I have sent emails to chinmay but seems he is on an eternal honeymoon and its been over a month and a half since sending him tech files and info to look at. Is there someone else that can look at the tech files to figure out the issue. The AP does not appear to physically reboot but maybe just the wireless is rebooting? When checking client cpe their uptime is in days weeks months


We have seen no improvements to GPS issues with 4.6 or 4.6.1.

Getting a little tired of these ongoing issues. Years now with no real resolution.

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What are the indicators of the GPS not working for you? I am wondering if I’m having gps issues.

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The AP will stop transmitting if it loses sync for long enough. This holdoff timer is configurable under confirguration → wireless. If you have your radios in cnmaestro you will also see sync notifications if sync is lost/regained. You can also view this if you have your syslog mask set broadly enough on the AP.

If you are doing frequency re-use on APs at the same site, when one loses sync and before the holdoff timer has expired, it may drift enough to start interfering with the other AP significantly before it stops transmitting or re-gains sync.

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For us, it was pretty simple. When the GPS is properly working and locked, the GPS Status icon is GREEN. On the other hand, if it’s GREY, that means it’s then it’s turned off. And if its RED, then the GPS is not locked onto enough satellites to get stable timing and accurate location - which means it’s broken & not synced (or the AP is just booted up and no yet locked for a minute or whatever). So, it’s pretty simple - if it’s RED, it’s broken. If it’s GREEN, it’s working.


Further, simply check MONITOR → GPS
As shown below

  • the GPS Icon is GREEN,
  • the GPS Lat & Long are correct
  • the GPS Elevation is correct
  • the GPS Time is correct
  • there are 21 GPS Sats visible, 17 tracked

All this shows that the GPS is working. So, in our experience, there are no “subtle & unknown” type of symptoms… it either knows where and when it is, and everything is working, or it’s Red & Broken. Simply put, there’s no way for the AP to know it’s location and elevation and GPS time, without the GPS system working properly. And when we had a GPS down, the banner icon was RED, and the Monitor → GPS shows a bunch of blank and unknown info, with no Satellites tracked.


Thanks ninedd… that is basically what I was fishing for… as per what you shared that is exactly what I am seeing on my radios, so I do not think I have ever had GPS issues and I have only used cambium since 4.4.3. So was just curious if there was anyone having issues even if they have results like yours.

We are seeing that it has heaps of tracked satellites but is not able to lock to provide GPS Sync. Sync status shows down (RED).

We also see a massive amount of GPS flapping where it has enough locks but the Sync drops.

so did this ever get fixed ? with a newer version than 4.6.1??
we still have our smart antenna off because of this issue…