2 Replies Latest reply on Oct 17, 2018 4:54 AM by JeBl_3106276

    Wifi chip transmits when monitor mode is enabled


      I have made an application in WICED SDK that uses the monitor mode functionality. I have noticed that whenever monitor mode is enabled (or if the channel is changed during monitor mode) the chip transmits a "narrow band"  signal with a duration of approximately 30-40 ms. I've boiled things down to the following simple application


      void application_start( )


          wiced_init( );


          wwd_wifi_set_channel(WICED_STA_INTERFACE, 6);


          while (1) {

              wwd_wifi_enable_monitor_mode( );




              wwd_wifi_disable_monitor_mode( );




      Every time wwd_wifi_enable_monitor_mode is called a high powered narrow signal is transmitted. In the test code above channel 6 (2437.0 MHz) is set prior to toggling monitor mode. In this case the narrow band signal appears at 2439.0 MHz as seen in



      Switching to zero span on 2439.0 MHz shows the time aspects of the signal



      Every time monitor mode is enabled (in the test application this i every 200 ms) these transmit signal can be observed. The measurements are done radiated on a CYW943907AEVAL1F board.


      How can I avoid this? These high powered CWs should not be there - my application should never transmit anything.


      Is it possible to completely disable the TX path of the module?


      I'm using:

      board: CYW943907AEVAL1F

      WICED SDK version:


      Any pointers on how to avoid this are much appreciated.