I'm using the
iw tool to configure a WiFi interface to sniff the air (monitor mode) on specific channel:
ifconfig wlan0 down iw dev wlan0 set channel 1 iwconfig wlan0 mode monitor ifconfig wlan0 up
The manpage for
iw says that the channel bandwidth is optional:
dev <devname> set channel <channel> [HT20|HT40+|HT40-]
But it's not clear what value of the three is the default and according to what it's chosen?
Using Ubuntu Ubuntu 12.04.4, kernel 3.5.0-45-generic.