On Dec 31 2019 and for some non-updated devices also in 2023, many users on this list saw Packetflux and Cambium units losing GPS sync, needing a reboot. Forrest looked into it and identified it as a GLONASS rollover bug in the GPS receiver model that both companies used on that current firmware (AXN5.1.1?). From a discussion at that time, that module was often chosen because it was one of the very few that offered very good quality 1PPS signal at anywhere near that price point.
Recently I saw a post of FB WISP group about mass number of separate Mimosa B11 radios going offline, radios acting half-dead. The explanation is: " So on radios made before August of 2016, we were using a GPS chip that hit it's rollover limit. Pretty lame and poor design on their part, but we weren't prepared for something like that to happen either. Not that we'd expect something like that to happen. Anything after August 2016 seems to be fine. I have a Nov 2016 unit that it's not happening to. Blocking the GPS signal makes it think it's 2015 again so it doesn't reboot to try and get your correct timing." It does worry me that a lot of the hardware that we use is more vulnerable than expected to changes/issues with the GPS-type networks, especially now that 2 of those biggest GPS-type networks are being run by governments with currently their own instability at the top. Given that IEEE 1588 can provide 1PPS (I don't know at that level of accuracy), and that some fiber switches and wireless backhauls can carry 1588, has anyone looked into using those with/for wider-network radio sync synchronization?
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