October 22, 2010 10:28
Why can't you connect to the NMEA stream? I don't have a Garmin 520, but I do have a Garmin GPSMAP 3005c. Garmin does not sell a 9 pin serial adapter for my plotter, but I was able to make my own. Once connected to my macbook via a USB-Serial adapter, I can then upload and download waypoints from my Mac. I create all my routes/waypoints with MacENC and upload them via GPSBabel over the serial cable.
I just downloaded and reviewed the installation manual for your 520. The 520 has two NMEA ports. You can pick either one. I will assume you want to use port 2 (thats what I use) for data transfer. First you need to buy a DB9 serial plug with solder connections (or crimp connections?) and also a 9 pin serial to USB adapter. You can get them at Radio Shack and some computer retailers (don't try the mac store, they won't have them!). The db9 connector should have some numbers indicating which pin is which. If not, use google to get a photo of a DB9 to consult. The pin numbers are always the same. You solder the grey wire on your Garmin GPS harness to the DB9 pin #2 (GPS NMEA Tx, Computer NMEA Rx). Then solder the violet wire to DB9 pin #3 (GPS NMEA Rx, Computer NMEA Tx). Then solder a connection from the black wire to pin #5 (ground). Thats it, now you have a serial connection to your GPS. If you want to use NMEA port 1 instead, consult your manual for the proper wire colors. Now you should be able to use GPSBabel to upload waypoints directly to the GPS, without using a data card. Even though you have everything hooked up properly, GPSBabel fails the transfer every once in a while. Just try it again, and it should work. GPSBabel never fails the transfer halfway through, it just needs a kick in the pants to get started once in a while.
I used a long piece of Cat 5 ethernet cabling to extend the serial port on my GPS to my nav station. Now I can leave my macbook at the Nav Station and I can upload/download all the waypoints/routes/tracklogs that I desire. At the end of every season, I download the complete set of tracklogs and save them. I can also leave the macbook running and MacENC will plot my position on the screen. I don't leave the macbook running very long that way, as the battery runs down to quickly.
email me if you need any further explanation: bob (at) funautical (dot) com
I just downloaded and reviewed the installation manual for your 520. The 520 has two NMEA ports. You can pick either one. I will assume you want to use port 2 (thats what I use) for data transfer. First you need to buy a DB9 serial plug with solder connections (or crimp connections?) and also a 9 pin serial to USB adapter. You can get them at Radio Shack and some computer retailers (don't try the mac store, they won't have them!). The db9 connector should have some numbers indicating which pin is which. If not, use google to get a photo of a DB9 to consult. The pin numbers are always the same. You solder the grey wire on your Garmin GPS harness to the DB9 pin #2 (GPS NMEA Tx, Computer NMEA Rx). Then solder the violet wire to DB9 pin #3 (GPS NMEA Rx, Computer NMEA Tx). Then solder a connection from the black wire to pin #5 (ground). Thats it, now you have a serial connection to your GPS. If you want to use NMEA port 1 instead, consult your manual for the proper wire colors. Now you should be able to use GPSBabel to upload waypoints directly to the GPS, without using a data card. Even though you have everything hooked up properly, GPSBabel fails the transfer every once in a while. Just try it again, and it should work. GPSBabel never fails the transfer halfway through, it just needs a kick in the pants to get started once in a while.
I used a long piece of Cat 5 ethernet cabling to extend the serial port on my GPS to my nav station. Now I can leave my macbook at the Nav Station and I can upload/download all the waypoints/routes/tracklogs that I desire. At the end of every season, I download the complete set of tracklogs and save them. I can also leave the macbook running and MacENC will plot my position on the screen. I don't leave the macbook running very long that way, as the battery runs down to quickly.
email me if you need any further explanation: bob (at) funautical (dot) com