Dual band

Fejes József jozsef.fejes at gmail.com
Fri Jan 5 12:19:39 PST 2018

> Yes this allows you to create 4 APs, but on the same frequency.
> The key here is not that you can create 4 APs, but the "channels <= 1", meaning the card can only operate on a single
> frequency.
> Dual Band usually means the card can operate on 2.4Ghz and 5Ghz, but not at the same time.
> I'm not aware of "any" card which supports multiple frequencies at the same time, not only from software side, but
> mainly from hardware side.
> How would this work? How would you isolate multiple transceivers transmitting at the same time?
> Scenario:
> Put 2 different cards into a single device, and put terminators on one, and a power meter on the other:
> When the card with terminators transmits something, you will still see the signal with ~20dB attenuation on the other card.
> BR
> Matthias

The Asus RT-AC88U router is very similar to the Asus PCE-AC88 card:
both contain a single BCM4366 chip (they definitely run with the same
chip firmware). The router can definitely operate in simultaneous dual
band mode (one channel in the 2.4GHz band and another channel in the
5GHz band). The antenna and MIMO configuration also hints at this
capability. Except the router runs Broadcom's proprietary wl, not

Anyway, this part is obsolete for me, as I got a PCE-AC88 for testing,
but it physically didn't fit in the enclosure of the HP microserver.
We'll never know if it would have worked or not, my guess is 50-50. My
plan B is two separate cards in a Mikrotik RB14e so problem solved.

However, the following still stands: it would be nice if hostapd could
create and destroy virtual interfaces on demand. It would be somewhat
similar that I don't have to put the card into AP mode with the iw
command, hostapd does it for me, and I could create virtual interfaces
with iw but hostapd could do that too. Then I could run one instance
of hostapd with two configs, and both configs could reference the same
physical interface. It's nicer than setting up the virtual interfaces
by hand and ensuring it happens before hostapd starts.

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