RT2860 -- proč nevidím "noise level"?

Dobrý den, na netbooku EEE 901 mám wifi kartu RT2860, driver rt2800pci:

$ lspci -nnk | grep RT2 -A3
01:00.0 Network controller [0280]: Ralink corp. RT2860 [1814:0781]
	Subsystem: Ralink corp. Device [1814:2790]
	Kernel driver in use: rt2800pci
	Kernel modules: rt2860sta, rt2800pci

Bohužel nejsem schopen vidět "noise level":

$ iwconfig
...
wlan0     IEEE 802.11bgn  ESSID:"TP-LINK_FC72AE"  
          Mode:Managed  Frequency:2.447 GHz  Access Point: 54:E6:FC:FC:72:AE   
          Bit Rate=36 Mb/s   Tx-Power=20 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=50/70  Signal level=-60 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:32   Missed beacon:0

Nebo:

$ iwlist wlan0 scan
wlan0     Scan completed :
          Cell 01 - Address: 54:E6:FC:FC:72:AE
                    Channel:8
                    Frequency:2.447 GHz (Channel 8)
                    Quality=50/70  Signal level=-60 dBm  
                    Encryption key:on
                    ESSID:"TP-LINK_FC72AE"
                    Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s
                              9 Mb/s; 12 Mb/s; 18 Mb/s
                    Bit Rates:24 Mb/s; 36 Mb/s; 48 Mb/s; 54 Mb/s
                    Mode:Master
                    Extra:tsf=000000139203c96d
                    Extra: Last beacon: 596ms ago
                    IE: Unknown: 000E54502D4C494E4B5F464337324145
                    IE: Unknown: 010882848B960C121824
                    IE: Unknown: 030108
                    IE: Unknown: 2A0104
                    IE: Unknown: 32043048606C
                    IE: IEEE 802.11i/WPA2 Version 1
                        Group Cipher : CCMP
                        Pairwise Ciphers (1) : CCMP
                        Authentication Suites (1) : PSK

Někdy to zas pro "noise level" asi hází nesmysly:

$ more /proc/net/wireless 
Inter-| sta-|   Quality        |   Discarded packets               | Missed | WE
 face | tus | link level noise |  nwid  crypt   frag  retry   misc | beacon | 22
 wlan0: 0000   52.  -58.  -256        0      0      0      0     32        0

Mám Ubuntu 10.04 + aktualizace.

Nevíte někdo v čem může být problém? Budu rád za jakýkoliv tip.

Neoficiální informace k Ostravské univerzitě

Dotaz: RT2860 -- proč nevidím "noise level"?