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Prevalence of DFS support in consumer WiFi devices?
I haven't found good sources discussing how well existing WiFi products work with DFS. Do any existing products detect radar in these frequency bands and allow the bands to be used when no radar is audible? Do most products just avoid using these bands entirely? Or has DFS now become a standard feature in every modern WiFi access point? There's an allegation in an Ignition Design Labs press release that "98% of
existing [2016] WiFi routers" don't do DFS. See [1]. Was that true in 2016, and is it still true today? Gnuish (talk) 21:58, 14 July 2020 (UTC)[reply]
Radar emits a special pulse (differs by country/jurisdiction). Before starting on a DFS channel, WiFi router must first listen for this pulse for a certain duration (1-2 minutes). If no pulse was detected, it can start operating on this DFS channel. Detection must continue during the course of operation. As soon as the router detects radar pulse while in operation, it must switch channel or turn off within few seconds.
As for as how well each manufacturer implements these, you can look at this video segment (timestamp at 39:12) where the guy uses Wireshark to capture the "channel change" sequence between the router and client during DFS, and determine if they are "good".
IANA WiFi Professional. So I don't know if the 98% is true, but definitely plausible for consumer routers. Due to the 1-2 minute detection window at startup, lack of 5G WiFi might be misconstrued as a broken router. --Voidvector (talk) 06:38, 16 July 2020 (UTC)[reply]
Now that a few years have passed (it's now May 2023) .... the comments above, plus some pages I found (https://www.asus.com/support/FAQ/1045936/, which has horrible (non-native-English) grammar but is still understandable, and this page https://netbeez.net/blog/dfs-channels-wifi/) both describe DFS, in what seems like a simpler way than this Wikipedia article. I'll try to improve this article if I get a chance in the next few days, and if I can put my finger on why I think this article here is a bit harder to grasp. (Other editors are, of course, welcome to jump in.)
My neighbors' 5 GHz channels are all using the non-DFS channels -- now that I have moved to a DFS channel, I have no other signals competing with mine. This is interesting -- it might not make much real-world difference -- but as of now, there's a giant (DFS) band in the middle of the 5 GHz spectrum that I can use all by myself! David10244 (talk) 00:54, 15 May 2023 (UTC)[reply]
