5ghz WiFi in AP Mode

[Meestor_X]

I just purchased a RPI3B+, thinking I would be able to get 5Ghz WiFi in AP mode. It seems I'm still only getting 2.4Ghz. Is 5Ghz AP mode possible?

[Tim Curtis]

Yes but it requires changing the value assigned to the hw_mode parameter in the file /etc/hostapd/hostapd.conf

You can read about the hostapd.conf file at the link below. Search for "Operation mode" or "hw_mode".
https://w1.fi/cgit/hostap/plain/hostapd/hostapd.conf

Another decent link for hostapd is below.
https://wiki.gentoo.org/wiki/Hostapd

[Meestor_X]

Ok, thanks!

Hopefully it will work on both bands.

[Meestor_X]

Does this mean the RPI can't create 2 APs (one on 2.4g and one on 5g)?

[Meestor_X]

Haven't had any luck getting the AP mode to work at 5ghz.

Tried:
#hw_mode=g
hw_mode=a # didn't work

Then added:
#channel=6
channel=0 # didn't work

Then added:
ieee80211n=1 # 802.11n support
ieee80211ac=1 # 802.11ac support

No go. Never saw the SSID on my scanner.

Put the hosted.conf back to it's default and the Moode SSID is back, on 2.4g

Anyone have any suggestions?

[TheOldPresbyope]

@Meestor_X

This is an RPi/Raspbian question. A quick Google search turned up a mixed bag of posts, most reporting failure but a few claiming success. 

Have a look at the Raspbian github issues, 802.11ac 5Ghz wifi AP in RPI 3 B+, for example. There's a number of posts to raspberrypi.stackexchange.com as well. Lots of posters seem to be changing parameters randomly---the hacker equivalent of the mathematician's "drunkard's walk". 

WiFi technology is a mess. The clash between requirements of different regulatory regions is even worse for the 5GHz band than it was for the 2.4GHz band.

Regards,
Kent

[Meestor_X]

Thank you for that additional info.

Looks like channel=0 was actually the problem. Has to be set to a channel for it to work in AP mode.

There's a lot of other parameters in the link you posted, but it seems those weren't needed in my case.

Thanks, everyone!