Reporting in.
So I received this dongle:
https://www.ebay.com/itm/Atheros-AR9271L-802-11n-150Mbps-USB-Wireless-WiFi-Adapter-Wifi-Antenna-for-Win/352856112189?hash=item5227dcfc3d:g:EkAAAOSwU2Jdz-h-
I can confirm that it works on Trisquel, but the reception is very poor. Even
with external antenna the reception is worse than laptop integrated. Maybe my
unit is faulty. And this dongle disconnects very often, probably because it
needs more power than laptop usb port is supplying, I could use it only in
externally powered USB hub. BTW, the build quality is also very poor.
Maybe people should buy from technoetical, although units there are
overpriced a bit.