Issues with 16.2 firmware and GPS generate sync

Recently we have seen an issue with GPS and the 16.2 firmware. Over the weekend I lost GPS sync from my CMM5 GPS antenna. I set my AP’s to generate their own sync (450m). None of my SM’s were able to register or even see the AP’s. I powered down each AP one by one just in case I was receiving sync interference and still the issue persisted. I was able to resolve the issue by downgrading to firmware 16.1.1

This is the second time this issue has occurred for us at 2 separate locations. Based off what we’ve seen there appears to be an issue with 16.2 and the 450m AP’s to generate its own GPS sync.


So just to make sure we’re on the same page… when you use the radios generate sync option, it’s not actually creating sync that can be used with other radios. So you will most likely see lots of self interference issues, especially if you’re trying to use back to back frequency reuse and/or adjacent channel sharing.

Lastly, if I were you, I’d set your AP’s to “autosync + freerun” and enable the option “free run before GPS sync”.

The AP’s were previously set to Autosync + Freerun. I disabled the other AP’s and left the one AP which was facing the customer to avoid self interference from the Generate sync. The only reason why I switched to Generate sync was because the GPS antenna was damaged due to recent storm activity and was no longer sending a sync to the CMM5 for the AP’s to use. The AP’s also rebooted due to the recent storm activity so the last boot up occurred when there was no last sync available. We have never experienced this issue before. The only difference is the use of the latest firmware 16.2

Hello Sir,

do you now connect back your customers even the self generate mode at all your PMP 450m AP?

My opinion is that if you have separate frequencies at all your AP, your will not have a self interference issue. The PMP 450m AP is quite robust to keep the good service.

You should have different frequencies set and reconnect all your PMP 450m APs.

Sincerely yours,

Niragira Olympe