Hi, Just set up a Linksys WRT1900 ACS and am trying to use the same channel as my old router(Channel 104, 5520). It appears that LEDE detects a Radar in that frequency:
I found this strange as my old router never complained. So, I moved down the channels and used channel 60, no RADAR detected but at some point the channel will change back to 36 and I've not found anything in the logs. Any suggestions?
It certainly looks like it began to operate on channel 60, and within five minutes detected radar and, as required by regulation, changed channels. Looks like it also may have ruled out channels 100-112 (5500-5560 MHz).
At least as I understand it, and perhaps only for North America, channels 52-64 and 100-144 are subject to DFS restrictions (there is a gap between those two ranges for wireless use). While weather radar is typically in the channels in the 120s, this doesn't mean that there isn't other radar or services operating or that triggers DFS. As an example, maritime / navigation radar also can operate in these bands.
If the channel number is important to you (point-to-point links, as an example), then I'd chose from the 36-48 or 149-161 ranges.
I'm attempting to not use the channels from 36-48(In the UK 144 upwards are not allowed) as there heavily congested in my area. I think there is about 20 of them. I suppose this could be that they are all detecting RADAR and moving down and my old router was not functioning correctly.
Out of interest how large/small would a RADAR need to be and what distance do they travel? It seems that all DFS channels are unusable in my location.
Given that the radars often have power output in the 10-100 kW range and have very narrow-beam antennas, "a long way"
https://www.metcheck.com/WEATHER/radar.asp shows current weather-radar plots coverage. Pick a rainy day -- looks pretty clear there this afternoon! Looking at the current San Francisco report suggests a 100-150 km radius for the "short range" image, and two or four times that for the "long range" image.
The other possibility is false positives on the radar detection, I'm guessing manufacturers are understandably going to err on the side of "hey there's some weird crap on this channel, must be radar"