Ublox NEO-M8N GPS + HMC5983 compass (mini) 3.3V 5V solders


I have two of the mini new GPS boards (Ublox NEO-M8N GPS + HMC5983 compass) and my question is regarding the 3.3V / 5V solder pads.
I use the GPS on PixHawk.

The problem is that when I solder the 3.3V pad with the middle pad, the GPS actually is not listening anymore, just a few sats 1-3.

The strange thing though is that when I remove the 3.3V solder, leaving nothing selected on the 3.3V / 5V pads, the GPS works just great getting many sats 7-12 !!

I tested this behaviour with a USBtoUART board which I use for GPS stand alone programming and tested with same results connected to the Pixhawk too.

So my question is this, do we need to select something on the 3.3V / 5V solder pads, or can we leave it without selecting anything?


Hi Christos,

Your problem seems crazy… I never seen that before.
I think you’re a good solderer,therefore your pad should be good.

Anyway your GPS will work fine with or without this pad. It’s here for other applications than Pixhawk (or ensure the best communication between the other board and the GPS, almost nothing changes).

Yes indeed a strange situation, yet since it works ok its just fine with me.
Actually I have a PixHawk with primary the NEO-M8N and a secondary NEO-6M and your M8N is indeed way better, it gets 3D fix in a matter of seconds and about 10 to 13 sats, whereas the 6M is taking ages to get a 3D fix and just about 5 or so sats.

One more question, is there any .txt configuration file for the M8N GPS board when attached to ArduCopter?


Yes it’s normal that the 6M is more effective than M8N. We changed the patch and the chip Ublox is more powerful.

At each start, the Pixhawk configures the GPS, no need to modify anything, or change some parameters or put any .txt file. :wink: