ePMP 3000 GPS Sync Up/Down

Is someone experiencing an intermittent synchronization with ePMP 3000 GPS? I have installed 2 units of ePMP 3000 and both the GPS are having UP/DOWN connection. I already replaced the GPS and radio but still the synchronization is UP/DOWN .The firmware version of the radios is 4.6.1. Please help.

Hi @BaiSaiBer,
which FW are you using?
Does AP have clear sky view?
Is there any LTE tower in the vicinity?
Is your GPS puck square or round? Did you try without it?

Hi @aka ,

I’m using firmware version 4.6.1. The AP does have a clear sky view and there is an LTE tower within the vicinity. The GPS is round and I have not tried without the GPS.

IMHO the best and absolutely most bulletproof, never fails to work solution is don’t use ePMP’s onboard GPS ( except 3000L because there is no other option) and instead use Sync over power. We have used packetflux sync injectors since back in Motorola Canopy days and in 13 or 14 years have never had a single GPS sync issue that was due to the Packetflux failing. I think possibly one of the biggest advantages using a sync over power is it allows you to install your GPS antenna at the bottom of the tower where it can’t see every bit of interference for 100 miles in every direction.

Cambium did come out with some “New & Improved!” pucks a while back. We got some and tried them on some 3000L’s we had removed from service. We only put a couple of 3000Ls back into service with the new pucks and they didn’t have any GPS problems for the few months we had them back up (ended up swapping them back out for other reasons).

The pucks they sent us are adhesive backed (not magnetic) and the part# on the package is H2M3A386180100 Unictron Technologies Corporation. Other than the 3M sticker cover on the back they are identical in every way to all the other round cambium pucks. I have not been able to locate these using that part# or find them on Unictron’s website so no idea if/where you can just buy them or if they are all 3M adhesive backed or if the ones coming with radios now are magnetic backed and completely indistinguishable from the older round pucks.


The new square gps pucks are an absolute must!
There is also new round ones but we only have one and its not on a 3kL (backup gps on a e1k which is sync’d with a packetflux system)

As Brubble has pointed out, no epmp3000L works with sync over power. I did have one that had the options on the interface and appeared to use sync over power but that turned out to be a broken firmware flash and the e3kL was just using the internal gps regardless.

Packetflux hardware is pretty much bulletproof and just works, even 150ft up on top of a grain elevator the syncbox jr. does just fine were the cambium puck does not. Though I will say that LTE interference will also kill off the packetflux system so plan either to place the syncbox on a tower leg that hides it from a direct LTE source or use a piece of tin to make a shield.

There are two sync injectors, one is canopy (cmm3/cmm micro) and another that is cambium sync (cmm5). Both work fine as long as you select the correct sync source in the interface. Both use the same syncbox’s. We have been getting the cambium sync as we are also using pmp450i radios which need cambium (cmm5, ugps) sync sources.

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