DFS broken in 3.X beta and production

Ever since updateing to 3.X we are getting DFS hits on all the sectors updated to 3.X We have never had an issue with this and all of a sudden wham.. This leaves us basically 2 usable channels in the 40 Mhz size in the reliable 5.7-5.8 range.

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As far I am concerned - DFS on 5 GHZ in ePMP is definately broken.

The firmware in the ePMP radios falsly reports DFS reception and shuts down the transmitter when the ePMP radios see any type of data activity on the channel that the radios are tuned to. 

In the remote area that we are at, there is NO radar signatures in the 5 Ghz band within 300 miles of us.

If the radios are set to a clear frequency with in the 5 Ghz DFS segment - they work. 

If you move your radios to another channel where Ubiquity radios are transmitting - ePMP radio falsely report DFS activity and quit transmitting.  That is not how DFS deteection is supposed to work.

I reported this to Cambium support in an email, but I am under the impression that they think nothing is wrong. 

We had to quit using DFS channels because of the above. 

Like everybody else, we are waiting on a fix.   

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Hi MarioL,

Can you contact me offline at daniel.sullivan@cambiumnetworks.com and I can work with you on debugging your system.


Hi Danny,

Can you contact me offline at daniel.sullivan@cambiumnetworks.com and I can work with you on debugging your system.


I am really happy to read this! I have been pulling my hair out since upgrading to 3.0 about DFS!  I get radar hits on every single DFS channel I try to put an AP on and there is no way that is possible.  Some channels get hit within seconds of putting the AP on it, some take 24 or 36 hours (perhaps those are real).  I can have two APs in the same area, both with omni's and on the same channel (geography blocks interference) and one gets taken out by radar and they other does not.

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Your lucky to get 24 hours, I get knocked out on ALL DFS channels in about 3 minutes.

Either one is terrible when you have paying clients on an AP. Just as soon as I think I have found a good channel, at 3am my alarms go off telling me 10 clients are off line and the AP is no longer transmitting due to DFS.  My Mimosa gear on the same channels have no problems at all. I just avoid the known doppler channels in my area and Mimosa has never had an issue.

Been running 2.6.2 for months without a single hit, after upgrading to 3.0.1-beta9 (also tested 3.0), i'm getting radar hits consistently on a few Access points, even after changing channels 80mhz apart (5500 to 5590 and all between). Most hits occur within just a few minutes which shut down the sector. Rolled back to 2.6.2 and no hits at all.

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Thank you all for your feedbacks.
We already are working on that issue and are going to provide fix as soon as possible.

Sorry for inconveniences.

Thank you.

Hate to dig up an old thread but we are in the same boat, we get random DFS hits an all ePMP radios on our network. I’ve been communicating to support but outside of asking me to change antennas and radios no luck there. It’s almost like the support team is more geared towards fixing client problem and had a limited ability to report up actual system problems. Original posters on this thread can you speak to your continued experience? I’m wanting to get this issue up and in front of Cambium to make this better for everyone.

We are operating ePMP 1000 and 2000, with the cambium sectors, and with the RF elements horns, as well as the fully stock cambium sectors, the new cambium sectors with the smart antenna. Pretty much any configuration you can imagine with ePMP and we see DFS hits on all versions. We have ubnt hardware deployed on some of the the same towers having never once having a DFS hit.

We currently operate on 3.5, I will note we did not experience DFS hits that we noticed on version


Ever since a competing provider came in and set up a Mimosa AP and a couple of Mimosa backhauls we have had to completely abandon DFS channels on anything that can even come close to seeing anything radiated from one of their antennas. Even one backhaul on a tower 6 miles away that their AP is on the very edge of it's vertical beamwidth had to be moved out of DFS (Backhauls and Micropops are really the only things we use DFS channels for anyway).  If they move their AP to a DFS channel that is even close to a channel being used by our gear anything we have that can even remotely see it will start claiming DFS events. 

In one location were we did not have the option to move the Backhaul to another channel so we had to replace the ePMP with a ubiquiti radio. No DFS events since then on that backhaul. But now of course I can't sync that radio with the ePMP backhauls so it makes that channel completely unusable by anything being fed directly form my NOC tower unless I continue to replace ePMPwith Ubiquiti backhauls.

 We are running our AP's and the few ePMP backhauls I have on 3.4.1  as 3.5+ breaks things that effect us. We was running everything on 2.6.1 and I don't remember what problem it was causing us that made us move to 3.4.1... I think it was the one that we would lose access to the radios or maybe he had to upgrade to get CNMeistro working (that certainly wasn't worth the effort)

We are 3.4.1 on DFS APs as well as 2000 APs (because of the STP bug).

Any update on this?

We have several APs DFS-ing with no way of being able to correlate which one are problematic. Using non-DFS channels isn't an option for us as we're in the UK.

This is driving us and our customers crazy and we're rapidly losing trust in the brand.

Can someone from Cambium please tell us what the status is on this please?


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We are also having issues with DFS radar false detects on 2000 APs.  Have had the issue on both 3.4.1 and 3.5.1.  We have 430 and 450 on the same tower and nearby towers never have a DFS detect.  Put a 2000 on DFS channel and multiple hits per week.  We also have a couple Mimosa B5s and they are not having DFS hits.  I thought the problem may be the B5s, however we have an AP co-located with a B5, both on DFS channels and only about 30  deg. separated with no detects.

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Still broken for me too. I have to keep our lone DFS (because of spectrum) PTP on 2.6.2 just so it stays up and in a clean channel :-/

Still no word on this?

And I thought we are the only ones. We are running 3.5 and having the same problems.

Any news? Is there any fix?


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Still working on the fix.

If you need more informations we can help, we have one sector right now with 0 clients and we can play with it.
Let me know.

Do you mind clarifying your responce of "still working on a fix"?  Do you mean that this issue has been ongoing for 2 years with no resolution, or that its previously been resolved but re-introduced again?

Ever since our first installation last year I highlighted DFS issues where there previously none on the replaced UBNT equipment, however channel management has allowed us to mitigate in the most part.

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