I managed to find AP-capable Atheros wlan card for mini-pcie, bought adapter card for pcie x1 and connected the small antennas that came with adapter card.
It works but signal strength is extremely bad, when I tested, my phone had maybe 1-2 "connection bars" when it was pressed right next to antennas. Pull it away about 20 cm and wifi instant connection loss.
I am using pfSense 2.1 x64 in router but it seems irrelevant, feels like some sort of hardware issue. Or perhaps physics issue? Resistance in antennas wrong?
Has anyone got any ideas what might be causing the bad signal strength?
I already did set the signal to 100% from pfSense WLAN options.
The Atheros driver has the ability to select which antennas it uses. If your card has several antenna connections you may not have antennas actually connected there.
You may have the wrong antennas. If they are designed for 5GHz use they will be very poor at 2.4GHz.
You may have a grounding problem. Many antennas rely on a ground plane to function correctly.
Only the first point there I could imagine reducing your range to 20cm.
you should probably wait for pfSense 2.2 before attempting much with 802.11