Setting the COM port and baud rate

This page was last updated on 09 February, 2014.

If XCsoar or LK8000 can't find and read the GPS receiver, you'll need to go to the Devices page of System Configuration and experiment with changing the COM port and baud rate.

Be sure to start the program in Fly mode. After making changes you need to save the configuration and exit back to the map display. At this point the program will display "Restarting the COM ports" and you'll have to wait a few seconds until it gets some data from the GPS receiver and responds to it. The response will be one of the following:

No messages appear and the glider symbol is at your current location.

The program is getting a signal and your location is being correctly shown. This is easier to see if you are somewhere that has a good GPS signal, i.e. outside where houses, trees etc. are not preventing the GPS from seeing the sky within the 45 degree cone above you, and have set your usual gliderport as 'HOME' in your XCSoar/LK8000 configuration. When you start your PNA it will come up with the glider symbol on the HOME location until it gets a valid GPS fix and then jump to your current location.

"GPS: NO VALID FIX" (LK8000 2.3p) or "GPS waiting for fix" (XCSoar 6.2.5) is displayed.

Your program is correctly connected to the GPS receiver but it isn't receiving a valid set of satellite signals and your program can't display your position.

"No Data received" (LK8000 2.3p) or "GPS not connected" (XCSOAR 6.2.5) is displayed.

The COM port number is wrong. Try a different port. Many PNAs have their GPS receiver on COM1 or COM7, so try these first.

I expect that there should be a different error message if the COM port is correct but the baud rate etc. is wrong, i.e. a message is received but is unreadable due to a baud rate mismatch between the program and GPS receiver but I have been unable to force this condition with my Binatone B.350 PNA, which works correctly at both 4800 and 19200 baud. However, other PNA's may require a specific baud rate to be set. This depends on the internal PNA design and on the GPS receiver and baud rate generator used. Commonly used baud rates are are 4800 (the NMEA_[*] default speed), 9600, 19200 or 57600 baud.

I've never needed to change the data format: it 'just works' for me at the default 8bit setting, but then again I use a Binatone B.350, so your experience may be different. I suggest leaving the data format on 8bit until you've tried all combinations of COM port and baud rate.

[*] The NMEA protocol describes how a GPS receiver sends position, height and time data to the devices that use this information.