(well, kind of "solved") NetworkManager no longer picks up 5GHz SSID
 

My d-link wifi router offers dual wlan, 2.4 and 5 GHz. Suddenly NetworkManager no longer picks up the 5GHz SSID (but my Android phone does).
I'm on an updated -current and have looked at the changelog for the latest upgrades (Aug 2 and 4) but can't find anything there that could explain it.
Suggestions welcome.

Can you post the output of this?

Thanks for the suggestion, jostber.

Digging deeper I realised that it's all about faulty memory - mine, not my laptop's.

The router is new, and I was 100% sure that I had seen both the 2.4GHz and the 5GHz SSID show up in nm-applet. But after setting up my desktop, laptop, phone &c. I must have mixed things up. My laptop has an Intel N7260 wireless card, and even if itäs supposed to handle 802.11 b/g/n it's actually a single band card without the 5GHz band.

BTW, the devices supporting the 5GHz band are known as using the "802.11 ac" protocol.

And the Intel N7260 wireless card is not aware by 802.11 ac and will never be. ;)

Reality is a bit more complicated: there are at least two different N7260 cards, one b/g/n (2.4GHz only) and one a/g/n (2.4 and 5GHz).
The 802.11 n standard can theoretically handle 5GHz even if b/g/n cards rarely do so (if ever).

802.11 AC, this way is called.

There's also AD (60GHz, for wifi display) and AX, the last one able to give up 11Gbps transfers. ;)

And nope, the N and AC protocols aren't compatible.

802.11ac is in fact backwards compatible with b/g/n. 802.11a, however, is incompatible with b and g.