Why Atheros WiFi card is so unstable?

[Yuri]

I have Linux box sitting next to FreeBSD box that has a very cheap 
Airlink 101 card but has no problems connecting to my WiFi network.

Every time when Linux box says that quality of connection drops below 
10/100 FreeBSD box shows "status: no carrier".
Linux connections still function ok.

I even bought a large WiFi antenna for FreeBSD box but still have this 
problem.

Is there some "sensitivity" parameter that driver may be setting too low 
on the card?
Why wouldn't the quality of connection with Atheros card be so unstable 
on FreeBSD?

7.1-STABLE
ath_hal: 0.9.20.3 (AR5210, AR5211, AR5212, RF5111, RF5112, RF2413, RF5413)
ath0: <Atheros 5212> mem 0xcffe0000-0xcffeffff irq 16 at device 5.0 on pci0


Yuri