I've tried the LEDE-Project build and a self-built 17.01 on my R7800. Both work well for most things, but the 5G WiFi doesn't come up predictably. If I fiddle around with it (disable/enable, change name, change channel, run a scan, etc) several times, I can usually get it to come up (as seen from another LEDE router I use for monitoring, or from a PC). But it usually takes several tries. It doesn't come up reliably after a reboot (although it comes up sometimes.)
Is there a good way to troubleshoot this? I have access to the uBoot console & TTY...
@Doppel-D I should probably do a few complete power-off / 30 secs / power-on cycles...I've been doing a lot of fiddling with the configuration and reboots; maybe I messed something up that really needs a clean power cycle to get straightened out.
@jwoods this actually started because I noticed that channels 100-140 (more or less) were really empty in my office, whereas all of 2.4GHz and a lot of the low and high 5GHz channels were crowded. So I tried to bring the interface up on 120 and started having these problems. However, switching back to auto or a high or low channel didn't fix things.
Is there something special about the mid-range channels? I think Wikipedia said they're recently approved for indoor use only, and they conflict with weather radar?
I will certainly set up WPA2-PSK and AES before I use this box for anything real.
I was just reading that article! It looks like 50-144 are supposed to use Dynamic Frequency Selection, and that the particular channel you use has a corresponding bandwidth. I'll have to check the bandwidth and make sure it's right -- I guess that might confuse another box monitoring the airwaves.
Any reason to avoid 50-144? I can see quite a lot of APs outside that range, and none in it. So either there's something wrong with it, or it requires more technical ability to use successfully than most people have (which seems like it'd make it a great place for me, if I can figure it out!)
In many countries, operating WiFi devices on some or all channels in the 5GHz band requires radar detection and DFS (explanation). If you define a channel in your wireless config that requires DFS according to your country regulations, the 5GHz radio device won't start up unless OpenWRT is able to provide DFS support (i.e. it is both included and enabled). More technical details of the Linux implementation can be found here.
DFS works as follows in Linux: The driver (e.g. ath9k) detects radar pulses and reports this to nl80211 where the information is processed. If a series of pulses matches one of the defined radar patterns, this will be reported to the user space application (e.g. hostapd) which in turn reacts by switching to another channel.
DFS and radar detection is fully supported in Chaos Calmer. On Barrier Braker, it may be necessary to replace the default wpad-mini package with wpad (the full-featured package) or hostapd and wpa-supplicant (you may wish to use a wired connection to the access point to carry out these changes).
If you compile OpenWRT yourself, you need to set
CONFIG_PACKAGE_ATH_DFS=y
to enable DFS support. Without it, DFS-requiring channels cannot be used. At least for the ath9k driver you may also need to set
I personally would not turn DFS support on for my router.
After reading a lot about the regulatory requirements & so forth, I think you're right. If DFS works seamlessly, it should be OK, but there are backoff and extended-time disables that can happen (e.g. if the router detects a signal that looks like it might be radar) and if you don't know about them, it just looks like what I saw, "wifi doesn't work!"
I don't know for sure whether the problems I was seeing are related to DFS, but I have important business-related traffic that I need to have carried reliably, so I'll just use a regular channel. DFS is interesting, though, so I'll probably keep poking around until I understand it!
I've tried switching channels and the width, but there's no effect whatsoever.
Both radios are being reported working and broadcasting by LuCI, but I can't see the 5Ghz network from either of the devices available which are a a few Apple computers, an iPhone and an Android phone.
I have also tried switching the country code, and that has not worked either. I am in Japan so tried JP and US. Literally no difference: the 2.4Ghz network is always visible, the 5Ghz one is just not there.
Typing the network name hoping it's there but hidden also doesn't work.
Would be awesome if anyone had a suggestion. Thank you.
It looks like 50-144 are supposed to use Dynamic Frequency Selection, and that the particular channel you use has a corresponding bandwidth. I'll have to check the bandwidth and make sure it's right -- I guess that might confuse another box monitoring the airwaves.