jon@jonnixbox:~$ sudo ifconfig wlan0 down
jon@jonnixbox:~$ sudo iw reg set BO
jon@jonnixbox:~$ sudo iwconfig wlan0 txpower 27 fixed
Error for wireless request "Set Tx Power" (8B26) :
    SET failed on device wlan0 ; Invalid argument.
jon@jonnixbox:~$ sudo ifconfig
eth0      Link encap:Ethernet  HWaddr 00:1e:68:d1:75:d4
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:4
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:43

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:5068 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5068 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:946288 (946.2 KB)  TX bytes:946288 (946.2 KB)