Time to invest in better GPS/Sync system?

Just looking for some advice on GPS with epmp 3000… should I maybe abandon the internal/puck system and invest in packetflux or cn tower switch?

We have been using packetflux for 14’ish+ years and I don’t have a single bad experience with it or a single failure that I can recall. I even use the syncinjector unit to power non-cambium non-synced devices just because it saves space in the enclosures.

That said, if money was no object then those cambium switches could replace both our packetflux hardware and the Mikrotik switch in the enclosures. That would reduce complexity and space needed ! But they have a lot of very expensive features apparently and I just needs simple GPS sync/power and switching. So way more money than I can justify.

appreciate the reply, I think I will d the same and stop relying on the built in gps of epmp 3000 radios/puck setup. So is there a packetflux setup that I could power and sync 3-4 epmp 3000 and a couple ptp 550?

How much of an improvement in stability and performance would one see using a packetflux setup?

You need one SyncBox Junior Basic Version - PacketFlux Technologies
This is the GPS receiver/antenna you mount it were it can see the sky/sats. It connects to the syncinjector with cat5/6 ethernet. I normally mount them on the outside of the enclosure or building the enclosure is mounted on. We do not have any mounted more than 15ft off the ground.

One of these for every four radios PowerInjector Plus Cambium-Style Sync - PacketFlux Technologies
They provide CMM5 timing and have a port for plugging the above sync receiver into and then another port for daisy chaining however many of these you need (all done with plain old cat5/6 ethernet cables).

You need power. You can power them via your own DC plant if you have one or other DC power supply of your choice or they sell these (24v and 48v versions. 3000 and PTP550 will run on 48v) 48VDC 2.5A Power Supply for various products - PacketFlux Technologies

You can also get a SiteMonitor Base 3 - Classic Edition - PacketFlux Technologies
It allows you to monitor voltages and sats and power cycle ports. I can’t really say anything about these, I have one but I’ve never got around to playing with it.

I don’t know what you are asking here exactly. GPS sync is a “It works or it doesn’t work” kind of thing. The AP’s onboard GPS needs to be able to track at least 3 sats in order to maintain Sync, being able to track more does not make it work better it just allows you to lose some without losing sync. So an AP tracking 20 sats does not work any better/different or have any better performance than one tracking 3 sats. The stability hit however is the AP tracking 20 sats can lose track of 17 sats and still provide sync while the one with 3 sats can not afford to lose track of a single sat.

There is no difference in the performance of an AP tracking 25 satellites and one tracking 3 all that matters is it can track enough sats to to maintain sync.

So, if your AP’s are not shutting down because they are dropping below 3 sats tracked and losing Sync then using a different Sync solution will not do anything at all for stability or performance. If however you are having AP’s stop transmitting because they are losing GPS Sync then the packetflux or CN Switch should remove that problem entirely.

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I really, really appreciate you comments and information!!

So based on my pic this is working fine? On all my sectors that look like the above picture seem to perform worse where others that look like this…

They Perform better… maybe just coincidence? I had posted once before with a similar pic that showed very little yellow and mostly gray for SNR and others had said that it didnt seem right and should be concerned. I am a bit discouraged… this tower is very rural, we are the only WISP in the area and just cant seem to perform well. I really appreciate your help!

This graph basically shows Signal from each of the Satellites – so yes, with all that green, your GPS signals are fine on this AP. You may potentially have some other different GPS issue, but your signals on this AP are fine.

As others have said - GPS syncing is either locked, or it isn’t. Now, just to be clear, it is possible for an AP with low low signals to be locked, and then later to unlock when signals degrade, or when GPS interference get’s worse… But at any given moment, it’s either locked or not. That is the “binary” part that people are talking about. If an AP is Tracking 16 Satellites in the Green… or if it’s tracking 5 Satellites barely in the Yellow… the point is: if it’s tracking and locked, then it’s tracking and locked - and GPS will work the same either way.

SO - if GPS isn’t unsyncing (ie: if you’re not getting alerts that the GSP is going down) then GPS isn’t your performance issue. It doesn’t matter if you have 12 Sats in the green, or 4 in the yellow… if it’s enough to lock and to stay locked, then that GPS will work just as well as 12 or 14 green.

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What other issues would it be if I am not having alerts going off due to “unlocking”?

I have been getting this in last day or so…

Appreciate your insight!

That means the AP lost communication with that SM and that is most often a problem caused by Interference.

The only way I can see GPS sync being the problem here is if your AP is in fact dropping to less than 3 sats tracked but you have really long “Synchronization Holdoff Time” set. The setting for holdoff allows the AP to continue operating for X number of seconds after it has actually lost sync (tracking less than 3 sats). Cambium has said that when running on hold off the APs can go about 1600 seconds before they slowly drift out of sync with your AP’s and start causing problems with any AP’s that may be on the same or overlapping frequency.

I have seen some here on the forums recommend setting sync hold off to much more than 1600 seconds. If you have done that then it is possible that your AP’s are losing sync but continuing to run until they drift out of sync with GPS and start causing interference problems. Meaning the problem is still noise only it’s from your own APs.

Otherwise your issue is probably just good old fashion 5Ghz interference from other WISPs or WiFi routers or 1000’s of other noisy IOT junk. You can try turning on the Spectrum Analyzer on the AP ( the SA does to seem to run a little better on AP’s than SM’s) and if the client is an AC radio you may try running it there (all though in my experience it is almost completely useless/unreliable on the client radios)

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Thank you for your continued insight!! I will try and figure out if there is self interference… not sure where to start with that lol.
Here is the AP SA

Hi lads,

I had the exact same problem, with terrible SNR on GPS. I spoke to my Cambium chap and he sent me a bunch of 3M GPS pucks. My signals are now brilliant on all epmp radios.

You do not need anything but to swap out the original crappy pucks for the 3M ones and you’ll be happy, I promise you.

This AP had no green signal whatsoever this morning. Today I added a 3M puck and now its green for days…

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I am glad to hear that you got that worked out! Where you experiencing really low snr on all sats tracked? or was it GPS sync loss? or both?