Hello and welcome to a thread dedicated to 802.11ac Wi-Fi and specifically to questions and issues related to 160 MHz channels. 802.11ac standard has been with us for a while now and so were - in theory - 160 MHz channels, however there were no Wi-Fi cards capable of 160Mhz channels until Intel 9260 came along, so that part is new. As such people are not aware of specific issues that arise only or mostly when those channels are used. Let's get through some of the basics: 1. How 160 MHz channels came to be? These channels are either two continuous 80MHz channels bonded together (usually designated as 160) or two separate (not continuous) 80 MHz channels working together (usually designated as 80+80). The second type - 80+80 is far better for a couple of reasons - one is that it's hard to find a clear/free 160MHz of 5GHz band but it's much easier to find free 80MHz, so one could use two free channels to form one super-channel Secondly one could use two non-DFS channels to form 160MHz channel i.e. one from the lower part of spectrum (channels 36-48) and one from the upper part (149-165) omitting the middle part where DFS is required. This all sounds great but not all of the routers support 80+80 and moreover we are not sure that Intel 9260 and its twin Killer 1550 even support that. 2. What the hell is DFS? DFS is Dynamic Frequency Selection - it's goal is to stop routers and other 5GHz devices interfering with weather radars (see this file if you're interested in details - PDF). The idea is that the router will detect specific radar patterns and will switch channels to avoid causing interference. Also once the router is booted up, before the 5 GHz radio starts it's going to scan the channel to make sure it can be used without causing interference to any radar installations. On most channels that scan takes 1 minute and in that time it might seem like 5GHz radio is not working, but on some channels it takes 30 minutes (I don't have a source for that but it seems on upper channels) See this for details. Oh and the channel the radar got detected on gets blacklisted for 30 minutes. 3. On what channels is DFS required? That depends on where you live - as usually rules are different all around the world. In the US DFS requirement starts from channel 52 (lower boundary is 5250 MHz) and goes all the way to and including channel 144 (upper boundary 5730 MHz). As a result in the US non-DFS frequencies are 5170 MHz to 5250 MHz (that's 80MHz wide) and 5735 MHz to 5835MHz (100MHz wide). As you see there is no way to for a continuous 160MHz channel on any of non-DFS frequencies. 4. What's wrong with DFS? 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. Before the router can establish new network on a new channel it has to scan it - which as mentioned above takes no less than a minute. As a result your wireless connection might get dropped at any minute stopping any transmission and possibly damaging data and then there will be no SSID to connect for another minute. 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. 5. I don't live near the airport so radars are not a problem for me. Why should I care? First of all what is near? According to this source "near" is defined in DFS documentation as anything within 35km (21 miles) of a radar installation. That does not really sound like "near", does it? If you live in a city your chances of being within 21 miles of an airport are rather large - welcome to DFS zone 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. As such I suspect my router is not picking up any radars - more like something on 5GHz operated by one of my neighbors. 6. Why not disable DFS, than? This can't be done - it's built in the driver and as such if it's deployed by the manufacturer of the wireless chip, it can't be disabled. 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. 7. But speeds are great with 160MHz channels. 100MB/s over Wi-Fi! That is true - it looks nice and all. On a free channel in the DFS zone I managed 96MB/s download over ftp from NAS. Not that the connection was able to stay reliably on for 24 hours... What would you rather have - a slower connection that's reliable or a flakey one that's insanely fast? 8. My router does not disconnect like that! Maybe it doesn't - maybe you live far from radars and there is no interference that your router picks up and wrongly recognizes as radar interference. Or maybe you just don't know it happens. When a router disconnects you from 5GHz network your notebook will most likely automatically reconnect you to 2.4 GHz network (which is still working). If that doesn't happen your 5GHz SSID will reappear on a new channel after 1 minute and your computer will re-connect to it. And there is no point going to router settings to check the channel - UI doesn't get updated by the radio driver. If you chose channel 36 and you ended up on channel 122 as a result of DFS intervention, your router's GUI will still show 36. The only way to check is to use a network scanning software. 9. What can I do? Not much really but when upgrading to 160MHz router buy one that supports 80+80 MHz non continuous channels. If this option is not available, you will not be able to avoid DFS channels. Also make sure to research what channels are supported - 80+80 needs to consist of lower channels an upper channel to avoid DFS ones. If your router supports lower and middle channels but not the upper ones, that won't help either. Also in some countries like Japan, Israel or Turkey upper channels are not available by law anyway. And in case you think that you can just choose a different country from a drop-down list to circumvent that - it might not be the case. Some wireless devices ignore that setting. 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. While it's still not clear if Intel 9260/Killer 1550 support non-continuous 80+80MHz channels, if it does you're in luck, if it doesn't some other card will come along and replacing a $25 card is much easier than a $250 router. Any questions, clarifications are welcome.