Load the driver, bring it up, capture frames with tcpdump
Load the driver as follows:
make -C /usr/src/sys/modules/rtwnfw load
make -C /usr/src/sys/modules/rtwn load
make -C /usr/src/sys/modules/rtwn_pci load
This should create an rtwn0 device. Create the wlan0 interface by running:
ifconfig wlan0 create wlandev rtwn0 wlanmode monitor channel 6:g
ifconfig wlan0 up
Adjust the WiFi channel to a local channel. Then I run this command to start receiving data.
tcpdump -n -i wlan0 -y IEEE802_11_RADIOreceiving data.
As cited, if you bring the interface down and up, the tcpdump command inconsistently fails to receive data or receives data in sporadic bursts. This is due to the changes in 960c0f3d880f9767027c05614f2184ce4b93fa99.tcpdump -n -i wlan0 -y IEEE802_11_RADIO