GE864-GPS Internal LNA

3 thoughts on “GE864-GPS Internal LNA

  1. Hi,
     
    We are using GE864-GPS with an active GPS antenna.
    So we need to disable the internal LNA of the module.
     
    1)  I can disable the internal LNA with (MID 178,2). is this configuration stored in Non volatile memory? or should I send it everytime the module its turned on?
     
    2) If I dont disable the Internal LNA with (MID 178,2) and use an active GPS Antenna, the module still can get a GPS Fix. Is this normal behaviour?, does this mean that I dont have to disable the internal LNA in order to use an Active GPs Antenna?
     
    Best Regards, 
     
    1. Hi Alberto,

       

      are you
      using the GE864-GPS in stand alone configuration?

       

      If the
      answer is yes, you need to send the configuration Tracker Message (MID178,2) to
      configures the internal LNA amplifier in low gain mode and drives HIGH the
      GPS_EXT_LNA_EN signal that can be used to enable an external LNA.

       

      However
      remember to wait for SiRF ACK of MID178,2, and also for have full effect this
      command required a Hot Start .

       

      MID178,2

      Unfortunately, if your design does
      not have any battery backup, and you removed the Vbatt, it will be necessary to
      set these parameters on the startup again.So if the module was turn off and
      turn it back on, without removing the Vbatt this settings will be saved, and it
      will be available at next power up, but if the Vbatt will be removed the module
      will start with default configuration.
       

       

       

       

      Attached
      the SiRF Star IV-GE864 GPS application note with configuration command.