Yet ANOTHER blown B5 Ethernet port


@jack6 Most of my runs are less than 250’, none are over the Spec of 310’. The one that is currently having a problem is a 120’ run at 80’ ALG on a rail way tower. Railway guys do grounding like telco’s do grounding and they did the installation, not my guys.

The flapping problem is so random that testing at the tower site is not practical. I have a test rig that we put them on in the shop, with a 300’ cable run and they might run for a week at gig and then flap for an hour or a day, or not at all. Brand new B5/C’s do the same thing.

All sites are powered with Netonix POE switches. I’ve tried driving the Mimosa on Both 48V and 48VH (which is power on all four pair) when they are flapping and it doesn’t matter.

I RMA’d 2 B5’s a couple years ago that were doing the same thing - I never heard back.

I am 100% certain that Mimosa knows they have a problem and 99% certain that they know what it is - BUT they refuse to step up and recall their broken products - which have been faulty since day 1. I refuse to support that idea.


Ian1, I feel your pain. I have had the same problems. I have done all of the recommended things which have been suggested. I have learned way more about grounding than I ever wanted to know and I am a mechanical engineer. Recently Mimosa replaced a good many of my out of warranty radios because of the same issues you are having, primarily port flapping, some of mine had water in them. Two of my B11s went down yesterday early and did not come back until today, no power outage, no reboot, the Ethernet ports just quit working for 24+ hours, tower completely down, (traffic all rerouted, gotta love OSPF). I appreciated Mimosa sending me the replacements. And believe it or not my problems with these units has all but disappeared! Those darn Ubiquity radios just work! I left the Mimosa replacement radios on the shelf for future use to replace the few Mimosa links I have left and I am not totally sure I will use them even then, but out of fairness I should because they said they had changed the Ethernet ports for the better in their manufacturing process. Oh, and if you check my other post, three of the replacement radios they sent did not work right out of the box, but to their credit, they replaced those too. I think the radio side of these radios is second to none, too bad the Ethernet side is just none.


@Dave1 The last B5 I bought - supposedly Brand New - there was a random piece of Hot Glue, about the size of a dime, rattling around inside the enclosure. Nothing says “quality control” like Hot Glue that wasn’t even applied properly.

A few people now have said Mimosa have fixed the hardware issue with the ports. But if they DID do that, then did they recall all the broken ones in the distribution channels ? Because if they didn’t then all that broken crap will still be sitting on shelves and it’s a crap shoot if you get one of the “fixed ones” or one of the “old” ones.

There’s no way to know, but since they have ALWAYS avoided admitting that there IS an Ethernet port problem I really really doubt they would recall the junk that’s already out there.

I have never been a UBNT fan, in fact I have avoided them and mostly hated on them since the SR9/XR9 fiasco, but since I started this thread we’ve setup 2 new links with UBNT AF5x and no issues. I have a few ISO backup links running for ~4 months now and no issues. Yet it’s very rare when I get a week without a Mimosa flapping somewhere in the network.