More or less continuous radar detects

Products ePMP
1

Hi!

Mid-november we replaced several long running PtP links from some no-name vendor with AC-chipset (and no DFS) with ePmP 4500L and RF Elements UltraHorn antennas. 20 MHz bandwidth, distance 12 kms.

All works fine, except one of them. First two months it was ok, we had some radar detects, but not many, maybe once a week or so. But last month or so it has been useless, many radar detects every day, with 30 minutes downtime each time. Last day it’s been more or less continuously:

2025.03.07 09:36:01 kernel: [1247973.545204] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.07 09:04:33 kernel: [1246085.596086] SM disassociated from AP[bc:e6:7c:22:da:38] F=5490 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.07 09:00:27 kernel: [1245840.171688] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.07 08:55:33 kernel: [1245545.558604] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.07 08:50:46 kernel: [1245259.110978] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.07 08:19:24 kernel: [1243376.605062] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.07 08:14:37 kernel: [1243090.003957] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.07 07:43:15 kernel: [1241207.561410] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.07 07:38:27 kernel: [1240919.552467] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.07 07:07:04 kernel: [1239036.595940] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.07 07:02:17 kernel: [1238749.531093] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.07 06:30:54 kernel: [1236866.594830] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.07 06:26:14 kernel: [1236587.219286] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.07 05:54:45 kernel: [1234697.554275] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.07 05:49:58 kernel: [1234411.173084] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.07 05:18:36 kernel: [1232528.555935] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.07 05:13:49 kernel: [1232241.530960] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.07 04:42:26 kernel: [1230358.600743] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.07 04:37:44 kernel: [1230076.988905] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.07 04:06:16 kernel: [1228188.560711] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.07 04:01:30 kernel: [1227903.136469] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.07 03:30:07 kernel: [1226019.556791] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.07 03:25:20 kernel: [1225733.177327] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.07 02:53:58 kernel: [1223850.560707] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.07 02:50:52 kernel: [1223664.614623] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.07 02:19:22 kernel: [1221774.596976] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.07 02:13:08 kernel: [1221401.145317] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.07 01:41:40 kernel: [1219512.553123] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.07 01:36:53 kernel: [1219226.478055] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.07 01:05:31 kernel: [1217343.596170] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.07 01:00:46 kernel: [1217059.207238] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.07 00:29:22 kernel: [1215174.600035] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.07 00:26:12 kernel: [1214984.964116] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.06 23:54:46 kernel: [1213098.599192] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.06 23:48:26 kernel: [1212719.011085] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.06 23:17:04 kernel: [1210836.595659] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.06 23:12:24 kernel: [1210556.541062] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.06 22:40:55 kernel: [1208667.597813] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.06 22:36:08 kernel: [1208380.980965] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.06 22:04:46 kernel: [1206498.598253] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))
2025.03.06 22:01:34 kernel: [1206306.943603] SM associated with AP[bc:e6:7c:22:da:38]
2025.03.06 21:30:10 kernel: [1204422.593745] SM disassociated from AP[bc:e6:7c:22:da:38] F=5510 11axahe20. Reason: 35 (STA HAS DETECTED RADAR (ETSI))

This is the site in question. Image from Google Maps, from before the uppermost radio was replaced with ePMP 4500L and RF Elements UltraHorn. My question is if the roof could be causing my issues? Also, it was most likely covered with snow untill February - which could explain why it has gotten worse.

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{A2AB9AB5-3C79-4B9A-8323-26F49270346C}925×823 57.7 KB

This is 2-300 km from the nearest coast, 250 km from the nearest airport. There is no meteorological station in the district. The nearest weather radar is 100 km away, but there are mountains between, and we have other links in the area with no problems.

I really hope someone can say that the problem is very likely due to placement above that roof, and by moving it we should have less radar detects…

Bonus questions: it takes 30 minutes to reconnect after radar detect. Is there anything I can do to decrease that time? Unselect frequencies from the SM?

And there is no reason to swap which site is AP and which is SM? They both do radar detects the same way? (I read something about Mikrotik at least at some point did not do radar detect on SM, only AP)

Really desperate for help here! :slight_smile:

2

You could perhaps experiment with the Watchdog. It’s pretty meager, with barely any usable features - but it can reset the radio when one side is unable to ping the IP of the other side - and see if that helps you in some way?

1 Like
3

The reflective metal roof below the radio could certainly be an issue, especially when it is wet. Reflected energy and noise can both trigger false radar events.

Are you able to move the link to a non-dfs channel until you can try physically moving the radio?

2 Likes
4

Unfortunately there are no non-DFS channels available on the ePMP in Norway (I’m not 100% sure that is the correct interpretation from Cambium - but I haven’t double checked this).

Not sure If I’d get an answer here, but is it possible to install a different license code to get a non-DFS channel…?

But I’m glad you kind of confirmed that this can be the reason, not just me hanging on to wild theories :wink:

5

Good point… If I manually change frequency it comes back up within a couple of minutes. But not sure if a restart will do the same. Will do some testing! Thanks!

1 Like
6

Hello @sjordet,

I suggest you to Raise Ticket in the top right corner of this page and attach techsupport files from AP and SM on SW 5.9.2 right after a radar detection.
Our engineer will assist you to sort the issue. We can check first if the signature is a real radar pattern.
From my experience, some military bases can be blurred out in google maps.
My last case from Norway related to DFS had areal a radar detection somewhere at ski resort.
There are no non-DFS channels in Norway.

7

Thank you, @aka

I have already raised a ticket last week. #430261

Was not aware that you can check if the signature is a real radar pattern. That has not been mentioned by the engineer on my case.

This is in the bottom of a rather narrow valley in the middle of Norway. The only radar I can imagine here, especially in that particular area, would be from helicopters. But there wouldn’t be helicopters around here daily, weekly at best, and for sure not continuously like today.

Thanks :slight_smile: