Wi-Fi 802.11ac 1.7 Gbps (160MHz channels) advisory

Discussion in 'Networking and Wireless' started by downloads, May 1, 2018.

  1. bennyg

    bennyg Notebook Virtuoso

    Reputations:
    1,540
    Messages:
    2,341
    Likes Received:
    2,320
    Trophy Points:
    181
    The hardcoded behavior of this DFS sounds like a great way to clear a channel all for yourself. Spoof one of these radar signals and force all the routers in your apartment block off your new uncongested personal channel!
     
    Starlight5 and alexhawker like this.
  2. nosauce

    nosauce Notebook Consultant

    Reputations:
    20
    Messages:
    152
    Likes Received:
    36
    Trophy Points:
    41
    [​IMG]

    I think I remember reading on the changelog for the most recent firmware that I'm on, that they added DFS channels. So it might be a recent addition. I'm on Channel 104 (DFS):

    [​IMG]

    This is from Killer Control Center's Wifi Analyzer. What the does the circle portion mean? Maybe that the wifi card is capable of 80+80?

    Is all this Radar detection, damaging and losing data only apply to 160MHz? I'm assuming it applies to 80Mhz too? I haven't noticed any disconnections but as you pointed out maybe I'm not noticing it. I have 2.4 Ghz turned off. It's consistently on channel 104 (DFS) according to the wifi analyzer. If Radar was detected and the channel was switched, shouldn't it read a different channel? Or does it drop the signal again to switch back to 104 (DFS)?

    I thought being on my own channel without interference was a good thing. I mean, look at all the crap to the right and to the left! But if data is being damaged/loss on a DFS channel that's not cool. That's not cool at all.

    I'm not sure exactly what @Aivxtla meant by "power limits are much lower". And despite what the graphical depiction of the wifi analyzer indicates things worked fine when I use the 149+ non-DFS channels.

    So should I be using the non-DFS higher channels (149 to 161 range) instead of the DFS channel that I'm using?
     
  3. Aivxtla

    Aivxtla Notebook Evangelist

    Reputations:
    333
    Messages:
    424
    Likes Received:
    563
    Trophy Points:
    106
    Here is the chart showing legal power limits at various frequencies:
    https://apps.fcc.gov/kdb/GetAttachment.html?id=1K3EcgPRatUcWMwkA+uROw==&desc=905462 D06 802 11 Channel Plans New Rules v02&tracking_number=27155

    149-165 is least restrictive, they upped the indoor power limits on 36-48 to be the same in 2014. DFS channels still have lower power limits than both the other ranges.

    If you are on CH104 and the router detected a priority frequency user on it, then it would completely kick you out of that frequency range/channel.
     
    Last edited: May 4, 2018
  4. downloads

    downloads Super Moderator Super Moderator

    Reputations:
    7,648
    Messages:
    8,640
    Likes Received:
    2,009
    Trophy Points:
    331
    I am somewhat lost in this battle against DFS, reason being, impossible things start to happen.

    I am connected via a 5GHz dongle that does not support DFS channels to my 5GHz network on channel 36 - which is confirmed by WirelessNetView.
    However at the same time another notebook of mine with Intel 9260 is running Wi-Fi Scanner and the network is clearly showing on channel 106 however this notebook (Intel 9260 one) can't connect to this network, despite the fact it is perfectly capable of working on DFS channels and can detect the network".

    There is a discrepancy here because WirelessNetView reports the channel that starts the bonded channel hence channel 36 while Wi-Fi Scanner reports the middle channel - hence channel 106.
    In reality we are talking about 5170–5330 and 5490–5650 - as you can see these not overlap in any way.

    So here is my problem - how the hell is this possible? It seems that since the dongle can't work on DFS channel and, it is definitely working than this is the channel the network is really on. However why would another notebook detect it on channel 106?

    And if you think that is not enough mystery - my phone can't detect the network at all. I don't think it supports channel 106 but it sure does support 36.

    I am somewhat confused. :rolleyes:

    EDIT: slightly edited for clarity (part in bold)
     
    Last edited: May 6, 2018
    Starlight5 likes this.
  5. nosauce

    nosauce Notebook Consultant

    Reputations:
    20
    Messages:
    152
    Likes Received:
    36
    Trophy Points:
    41
    It's a little hard to follow because you use words like "this" and it could be be referring to either laptops, but I think I'm tracking.

    Have you tried running both wifi detection software on both laptops? -- "WiFi Scanner" on the laptop with the dongle, and "WirelessNetView" on the laptop with the 9260. What channels do they detect?

    I know you said there was a disconnect between the channel you set your router to and the actual channel but what channel did you set in your router's setting?

    I have the google Pixel 1 and it picks up channel 104 (DFS) fine.
     
    Starlight5 likes this.
  6. downloads

    downloads Super Moderator Super Moderator

    Reputations:
    7,648
    Messages:
    8,640
    Likes Received:
    2,009
    Trophy Points:
    331
    I will have to wait till the issue reappears to do that - I've had WiFi Scanner running on one computer as it's a trial of paid software and WirelessNetView which is free, on another. At some point when the rial runs out I won't be able to use Wi-Fi scanner on both anyway.

    The channel I set on the router was 36.

    As for the smartphone - it does indeed support DFS - I just tested all of the 100 series channels, so the plot thickens.

    One notebook detects the wireless and connects to it at channel 36, the other detects but can't connect at channel 106 and the smartphone can't detect and because of that can't connect the network at either channel despite the fact that it should be able to do this on either one.

    Next time it happens I will bring up yet another laptop that has Intel 7260 and is runnig Win 7 and as such free version of inSSIDer.
     
    Starlight5 likes this.
  7. nosauce

    nosauce Notebook Consultant

    Reputations:
    20
    Messages:
    152
    Likes Received:
    36
    Trophy Points:
    41
    That's bizarre. It's gotta be an issue with your router or router setting. That's the simpler explanation. Otherwise it'd be that something's wrong with BOTH your phone and 9260 laptop which seems less likely. Reset Router? Is there a particular reason why you're using the lower channel 36, instead of the higher 149+ channels? Is this because HT160 only works on the lower channels?
     
    Starlight5 likes this.
  8. downloads

    downloads Super Moderator Super Moderator

    Reputations:
    7,648
    Messages:
    8,640
    Likes Received:
    2,009
    Trophy Points:
    331
    Once you reset the router all gets back to normal meaning all devices see the network on channel 36 and connect to it.

    My guess is that there is some failed DFS action here - as in the router discovers the radar (that in reality is not a radar) and then attempts to move to channel 106 or such and advertises the network as being at 106 but for whatever reason keeps broadcasting at 36.

    As such the network card that was connected at 36 would still stay connected and the one that attempted to connect at 106 wouldn't be able to since there is no signal there.

    But there is only so much that makes sense here - if the above was true than the device still connected at 36 wouldn't be able to reconnect if manually disconnected as it would be in the same situation as the other notebook where network is not where it's advertised to be. But I did manually disconnect the device working at 36 and it reconnected fine.

    Also another problem with my theory is that the phone did not see the network at either channel (I used Wi-Fi Analyzer app) - it would have to be in one place or another and the SSID is not hidden.

    As for your second question - 160MHz channels don't work in the upper channels indeed. Also I have an issue with not all devices being DFS complaint which prevents me from running the network at channel i.e. 114.
    If I stick to 36, the non-DFS ones will still be able to use it in 80MHz mode and DFS-complaint ones will be able to work at 160MHz channel width.

    There is an issue with those devices that I plan on starting a thread about and another one that I wasn't able to figure out for years.
    I am rather good at these sort of things so, rest assured I have proper problems that won't be easy to solve. :oops:
     
    Starlight5 likes this.
  9. downloads

    downloads Super Moderator Super Moderator

    Reputations:
    7,648
    Messages:
    8,640
    Likes Received:
    2,009
    Trophy Points:
    331
    The thing has happened again. This time I have some more info

    1. Notebook with Intel 9260 running Wi-Fi scanner shows (graph) the network at channel 106 yet it also shows that in the advanced settings the network advertises that it is at channel 36. Notebook is unable to connect to the network.

    2. Notebook with Intel 7260 running inSSIDer shows (graph) the network as running at channel 36 yet it cannot connect to the network.

    3. Notebook with Edimax USB card incapable of DFS using Wi-Fi scanner shows the network running at channel 106 (on a graph) despite the fact that this card cannot detect any networks on neighboring channels to 106 (and there are networks there) it is also showing in the advanced settings the network advertises that it is at channel 36. Note that this card (Edimax) doesn't work at channel 106. The same notebook is also running WiFi Info View which shows that the network is running at channel 36.
    This notebook is capable of connecting to that 5GHz network.

    4. Smartphone running Wi-Fi analyzer does not detect this network at all despite the fact that it should be able to see it at either channel - 36 or 106.

    There is also an interesting part of log from the router:

    So it looks like radar got detected on 160 MHz channel 36, the router switched to 160MHz channel on 106 and then radar got detected on 106 so the router switch back to 36 aka 42 (same channel with 80 or 160MHz width) and instead of creating 160MHz wide channel created an 80MHz wide one o avoid DFS part.

    Still, if that was the case than all of my devices would connect to 80MHz wide channel 36 aka 42 and only one did...
     
    Starlight5 likes this.
  10. Aivxtla

    Aivxtla Notebook Evangelist

    Reputations:
    333
    Messages:
    424
    Likes Received:
    563
    Trophy Points:
    106
    Note that Intel 7260ac has issues with HT160 enabled on routers. Every single firmware upgrade on the R7800 there is a note saying that the 7260ac has issues on routers with HT160 mode enabled and that “Intel is looking into it” since 2016 :D. Me and some others discovered the issue on the R7800 during test phase, I thought it was just a compatibility issue with the QCA9984 chipset but looking at yours it seems like a general issue now.

    https://kb.netgear.com/000055200/R7800-Firmware-Version-1-0-2-46
     
    Last edited: May 7, 2018
    Maleko48 and Starlight5 like this.
Loading...

Share This Page