Unable to set txpower on wifi card

Terry Polzin foxec208 at wowway.com
Mon Aug 30 19:28:53 UTC 2010


On Mon, 2010-08-30 at 11:45 -0700, JD wrote:
> On 08/30/2010 11:32 AM, Rick Stevens wrote:
> > On 08/30/2010 10:41 AM, JD wrote:
> >>     F13, latest updates.
> >> wifi card: Sparklan wmir-200N
> >> http://www.sparklan.com/product.php?func=view&prod_id=43
> >> Chipset: RT2860/RT2850
> >>
> >> The Datasheet says:
> >>
> >> Output Power
> >> 802.11a: 12.5dBm ± 1.5dBm
> >> 802.11b: 17dBm ± 1.5dBm
> >> 802.11g: 14dBm ± 1.5dBm
> >> 802.11an: 14dBm ± 1.5dBm
> >> 802.11gn: 14dBm ± 1.5dBm
> >>
> >> I am running in g mode (54megabits/s)
> >>
> >> $ sudo iwconfig wlan0
> >> wlan0     IEEE 802.11abgn  ESSID:"Deleted"
> >>              Mode:Managed  Frequency:2.462 GHz  Access Point:
> >> aa:bb:cc:dd:ee:ff
> >>              Bit Rate=54 Mb/s   Tx-Power=8 dBm<<<=====
> >>              Retry  long limit:7   RTS thr:off   Fragment thr:off
> >>              Encryption key:off
> >>              Power Management:on
> >>              Link Quality=70/70  Signal level=58 dBm
> >>              Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
> >>              Tx excessive retries:0  Invalid misc:0   Missed beacon:0
> >>
> >> I tried to set txpower to 14 per datasheet spec:
> >>
> >> $ sudo iwconfig wlan0 txpower 14dBm
> >> Error for wireless request "Set Tx Power" (8B26) :
> >>        SET failed on device wlan0 ; Invalid argument.
> >>
> >> The drivers that are loaded for this wifi card are:
> >>
> >> rt2800pci               7931  0
> >> rt2800lib              27818  1 rt2800pci
> >> rt2x00pci               5799  1 rt2800pci
> >> rt2x00lib              25936  3 rt2800pci,rt2800lib,rt2x00pci
> >> mac80211              182154  2 rt2x00pci,rt2x00lib
> >> cfg80211              135626  2 rt2x00lib,mac80211
> >> eeprom_93cx6            1305  1 rt2800pci
> >> crc_ccitt               1311  2 rt2800pci,irda
> >>
> >> Is this an issue with the wext driver or with the rt2XXXXX drivers?
> > Try "sudo iwconfig wlan0 txpower 14".  The "dBm" is assumed by the
> > command.  "man iwconfig" for details.
> > ----------------------------------------------------------------------
> > - Rick Stevens, Systems Engineer, C2 Hosting          ricks at nerd.com -
> > - AIM/Skype: therps2        ICQ: 22643734            Yahoo: origrps2 -
> > -                                                                    -
> > -           Vegetarian:  Old Indian word for "lousy hunter"          -
> > ----------------------------------------------------------------------
> Did not work :(
> 
> $ sudo iwconfig wlan0 txpower 14
> Error for wireless request "Set Tx Power" (8B26) :
>      SET failed on device wlan0 ; Invalid argument.
> 
> But setting it to 8 worked. So, why does it reject what the specs say is 
> legit power setting?
> 
How about 9?
Maybe they want the value in hex?




More information about the users mailing list