[walrus01]

It's even more annoying if you're trying to use cheap consumer grade 5 GHz point to point outdoor radio equipment (like a pair of $160 Ubiquiti 802.11ac based radios) to span a few km of distance, and choose a certain DFS part of the 5 GHz band because it's cleanest, but the link keeps dropping due to false "DFS hits" when there is actually no DFS weather radar nearby.

[fullstop]

I had to revert firmware on some of my ubnt equipment for a bit because the false positives were killing me. I live near a hospital, so maybe it was caused by the helicopters flying over? I believe that there was also a bug where once it detected "radar" it wouldn't actually recover until a nightly cron job ran on the AP, so it was very noticeable once it had happened.

I've moved to current firmware as a test and it is no longer a problem for me.

[jimnotgym]

Couldn't an aeroplanes onboard radar be the culprit?

[Gordonjcp]

I had to troubleshoot a microwave link about 15 years ago, where it would just stop passing traffic every so often. There wasn't any monitoring on it but if there had been they'd have spotted that it was running into DFS channel exhaustion. Of course, by the time I'd got to site the fault had cleared itself, but a bit of poking around and sitting on site all day eventually revealed the culprit.

Not a bad day too, nice and sunny, drinking a coffee from the burger van, watching the boats racing up and down the loch (one end of the link was to the "timing tower", a cabin with all the timekeeping equipment at the far end and built a couple of hundred metres off shore), watching the planes stacking at the Lanark holding-point for Glasgow airport, wow look, there's three of them just circling now, isn't that cool? Anyway no signs of bother from the netwo<PLUNK>

Scrolling up the logs, an error message about "cannot allocate DFS channel", and lo and behold all the channels are flagged as "RADAR interference".

I dialled the DFS hold time down to five minutes from an hour, and the problem went away. The spot wasn't usually that busy with planes and they typically weren't stacked for more than about ten minutes ever.

[wkat4242]

That's possible yes around channel 96. Weather radars are pretty specific in frequency because they rely on water resonance.