Question Adapter only seeing 5ghz band with 802.11a (NOT ac)

[Darktrevzy]

So we got a new modem to support voice through xfiniti triple play and since then I have only been able to even see the 5gz band when I allow duel band 802.11a/b/g, I have it on prefer 5ghz, and 802.11ac (have also tried 802.11n). I can get functional speeds by going by turning off duel band and using 802.11g (25ish down) but we are paying for 150 and I was getting it before through 5ghz ac connection. I updated firmware, updated my adapter drivers to no avail so far. any help appreciated. Haven't found anyone with this problem when I googled for it.
Modem is the only thing thats changed since previously connecting at ~150. Other computers on the network and my phone are connecting to the 5ghz network just fine.

Hardware: Win 10
Adapter - gigabyte GC-WB867D-I
Modem - Netgear CM1150V
Router - Netgear R7000P nighthawk

 

[Math Geek]

if other users can see it fine, then it's not the router but your adapter that is having an issue. i'd stop messing with the router to avoid bringing everyone else down with it.

the obvious things to try first are to:

check to be sure the card is properly installed and the outside antennas are properly installed.


then a fresh install of the newest drivers from gigabit will ensure the software is in place to run the card. most issues i have fixed with AC cards ended up being driver related rather than anything within the router.

https://www.gigabyte.com/us/Motherboard/GC-WB867D-I-rev-42#support-dl-driver

 

[Darktrevzy]

Okay, so I uninstalled the 'old' drivers (actually newer version) and installed the one you linked, still have the same issue. Messed around with a few other things hoping to get lucky lol that didn't work (shocking, I know). Installed adapter in a different pci slot, no change. Tried updating to windows recommended drivers again, no change, uninstalled everything under network devices in device manager and installed the 20.60.0.7 drivers again, same story. Don't really know what else I can do.

 

[Math Geek]

i'm at a loss then as to what may be happening. usually the software handles the connection management and if it is not then not sure what going on.

have you tried the card in a different pc to be sure it is working right? if it installs and runs with default windows drivers on another pc, then something wrong with your pc. if not, then can point at the card as the issue.

 

[Darktrevzy]

It's a head scratcher for sure. Sadly the other computers in the house are laptops or Macs. I sent gigabyte a ticket so maybe they will have something to add, but I don't have much hope. The adapter wasn't terribly expensive so I may just buy a new one and see if that does the trick.

 

[Math Geek]

i'm sure we're missing something but i can't figure out what that is.

 

[Solandri]

if other users can see it fine, then it's not the router but your adapter that is having an issue. i'd stop messing with the router to avoid bringing everyone else down with it.

It is an adapter issue, but the easiest fix is to adjust the router.

A few years after the FCC opened the 5 GHz band, it was discovered the the frequencies right in the middle of it were useful for a new type of doppler weather radar. It's increasingly used at airports to detect microbursts - sudden downdrafts which have caused several airliner crashes.

The FCC didn't want to close the 5 GHz band since it was already in extensive use. But they couldn't just allow it to destroy the usability of this radar. The compromise the FCC came up with was to reclassify 5 GHz channels 50-144 as DFS - dynamic frequency selection. WiFi equipment is allowed to use the DFS channels, but if they do they must monitor for weather radar. If they detect weather radar in use, they must automatically switch to a non-DFS channel.

https://en.wikipedia.org/wiki/List_of_WLAN_channels#5_GHz_(802.11a/h/j/n/ac/ax)

Most WiFi equipment vendors did exactly this. They use channels 36-165, but if the detect weather radar on channels 50-144 they will switch to a channel between 36-48 or 149-165. Where things got screwed up is a few vendors took the easy way out - they simply blocked their equipment from using channels 50-144 entirely.

The problem crops up when your router is DFS-capable, but your adapter blocks DFS channels. If the router happens to randomly use channels 50-144, DFS-capable adapters can see it and have no problems. But a DFS-blocking adapter cannot see the router at all, since it's incapable of seeing those channels. This is why the telltale symptom of this problem is that some adapters can see the 802.11ac network, while others cannot.

The fix is to go into your WiFi router's settings, and manually set it to use a channel between 36-48 or 149-165. That guarantees it is operating on a channel that even DFS-blocking adapters can see. In the future, you may want to consider upgrading to a DFS-capable adapter, since your adapter cannot connect to public hotspots which are using the DFS channels. It's a PITA digging up specs to see the exact frequencies an adapter supports. But in this particular case it's important.

Edit: Incidentally, this is why the US and EU were considering banning third party router firmwares. It's not that they were opposed to you hacking your router. It's that the third party firmware authors were being lazy and not implementing DFS detection and automatic frequency shifting. It was causing problems at airports which used doppler radar, and it looked like the only way to solve it would be to ban third party firmware. Fortunately the third party firmware authors got the hint, and most of the firmwares I've seen now support DFS.