Wi-fi 802.11ac 1.7 gbps (160mhz channels) advisory notebookreview gas nozzle icon


Almost everything, really. What happens is that once the router discovers what it thinks is a radar (based on the characteristics hard coded in the driver for your wireless chipset that are supposed to recognize radar patterns) your device has 10 seconds to vacate the premises.

It does so in an elegant and sophisticated manner – by dumping any and all connected devices and switching to another channel. And I mean that literally – it disassociates all wireless client immediately regardless of whether any data is transmitted. Also there is no roaming here, so clients do not get moved to another frequency/channel.

Mind you once the wireless connection is reestablished you’re not out of the woods yet. Any backups you might have had going are down at this point, any secure connections that require authentication will requite re-authentication (often manual) and anything you’ve been doing – streaming, downloading, VoIP is down at this point.

Secondly I very much doubt this patterns are correctly recognized. My router drops 160 MHz connection on multiple 5GHz channels roughly twice a day. Does it sound plausible that the weather radar would be switched on twice a day? Are the electricity bills that high?

I seriously doubt that whatever my router discovers is a radar. While I do live within 21 miles of an airport I do live in a large city and I do not live in a skyscraper. Basically I live on a low floor of a building some 8/9 miles from the airport and between me and the airport there are lots of tall buildings and skyscrapers.

What’s more if you’ve managed to disable scanning somehow, you wouldn’t be able to connect to any 5GHz networks anyway because DFS scan has to be complete before SSID can be created. Remember that 1 minute wait I mentioned before – that’s when the scan takes place and unless it’s finished SSID won’t be created.

I tested that on a router that has a separate radio which seems to be only used for scanning. It seems not to have been enabled before the latest firmware, but with the latest firmware it seems to be on and once I disconnected antenna from it 5GHz radio never got enabled. To clarify 5GHz radio was a separate radio that still had its antenna connected at the time.

I have one Wi-Fi card that completely ignores location set in driver advanced settings and goes with whatever location it has in its firmware. I also own a US bought Linksys router that will not accept the fact that I don’t live in the US. Location is set in its eprom along with Wi-Fi transmission power tables and it just won’t budge regardless of what you do.

Do see the need for radar-avoidance though. Certain squares in our grids supposedly see excessive rainfall peaks over and over again, but these are obviously caused by interference. The trouble then is that this makes sewage load and surface drainage predictions completely unreliable for these areas. And that’s just the known unknowns; the unknown unknowns have far greater consequences.

However, this DFS-scan method is an absurdly blunt instrument. These (weather) radars are known, relatively static quantities and there’s not that many of them. A simple IP traceroute/ping query to a bunch of pre-set IPs (e.g., one for and at each radar location) and you’d know the rough distance of the router to the nearest radar within a second. Next, send a magic packet to that radar’s IP and you’d know the frequencies to avoid and blacklist. Could make the query mandatory, if so desired, but you’d only need to do this once after the router boots; that dish isn’t going anywhere. Might even force a weekly check-up, just in case a new one is being built or the nearest one switched frequencies (also for any new, changed or disused IPs). And even then you’d have a grace time; the radar operator can be required to broadcast its new frequencies in response to packet-ing for at least a week prior to actually switching over to them. No need for that stupid 10-second-disconnect rule then.