Changing Sample Rate ( 1Hz - 5Hz ) via the Phone ?

Is there any S60 software out there that allows you to change the sample rate on Bluetooth GPS units ( IE Qstarz 818 ) without a PC. My next question is if there's no such software is there anyway of building it into a future version of RaceChrono ?

I only ask because I use my phone as a Sat Nav as well as my RaceChrono lap timer.


  • I did some experimenting with such feature few months ago, but I failed to make it work properly. I will try again with more time later.
  • Having just tested the Qstarz 818 set at 5Hz I have to say I'm very impressed with the battery life which ran for 20+ hours. So for me at least, I don't think there's a need to switch between 1Hz and 5Hz to save battery life.
  • Hi letterbox,
    how have you done to change Qstatz at 5hz?
    Real quality and precision difference with "normal" GPS antennas?
    Does it exist something better than 5hz nowadays?
    Sorry for "boring" questions, We are attracted to a purchase.
  • edited September 2008
    The Qstarz comes with a program called GPSView. You can download it from their website.
    Once you connected your computer via USB, you can change the rate via set up menu like above.

    If you have a old bluetooth MTK chipset GPS (iBlue, Qstarz, etc), try just try to change it first using bluetooth connection, then if not working do the mod chip method. I have found my friend's GPS able to change the update rate to 5Hz via bluetooth connection. No need for mod at all. But I doubt it will last 20 hours like the Qstarz BT-Q818 extreme.

    Make sure you buy the extreme too. Q818 has a 1Hz model.
  • I have Qstarz BT-Q818 extreme and a problem. Sometimes the receiver jumps from 5Hz to 1Hz by its self and I don't know why. I also use it for other applications, that don't utilize 5Hz mode and when I later try to use it in Race Chrono, it works in 1Hz mode. It would not be practical if that happened on a track day, when I am far away from a computer with GPSView program. Has anything similar happened to anyone? It seems I'll have to figure out if any specific application makes the problem or is it completely random occurence.
  • edited October 2008
    Maybe it switches to 1 Hz when you run out of battery? I have this item on my to-do list but haven't got to it yet, since I last tried (and failed) to do it.
  • Hmmm... It changes back to 1Hz for me when battery is flat. It is highly possible that other applications using the Qstarz extreme changes it to 1Hz, since QstarzGPSview allows me to change the extreme to 1Hz via bluetooth. I never have it change back to 1Hz while using racechrono. So I guess check the GPS running in 5Hz the night before and do not use other application on the day of the track day (if you could).
  • From the BT-Q818eXtreme-Users Manual:
    "NOTE: The default setting for Q818eXtreme is 1Hz. If you are no longer to use
    eXtreme 5Hz sport mode, either to switch it from software or to hard reset the
    GPS by unplugging the battery for 5 mins."

  • I think it's possible all right, I just haven't found the commands that do it. Haven't searched too hard though.
  • edited October 2008
    This problem happened twice and I don't think the battery would be the reason, because I never removed it and it also wasn't empty, so there must be another reason.
    Today I made a little test. I set it to 5Hz and ran all applications that use it, but it stayed in 5Hz mode, so I didn't find out if any program causes the reset.
    I guess the most safe way for now would be as takahashi suggested to check it the night before and not use any other applications until the track day is over.
    Thanks for the help, I'll report if I find the answers.
  • $PMTK182,1,3,002|$PMTK300,200,0,0,0,0 ;Log by time 0.2Sec (unofficial)
  • Hi,

    I have a Qstarz 818X that has 1Hz / 5Hz switch. However my data seems somewhat 'rough' on the display.

    How can I check whether my GPS actually sends updates with 5Hz?

  • danci1973: To verify if your GPS send 5hz data, start a new session in RaceChrono, "Start" / "Live timer" / "Toggle" and switch to satellite view, alternate view, and you see frequency data (1 or 5 hz).

    For control GPS type MTK / MTK II with phone and a java application, go to :
Sign In or Register to comment.