It occurred to me today that the combined draw of the Xmega and the GPS chip isn't likely more than 75 mA or so, so the buck converter is a bit of a waste. The final version will have a simple LDO instead. There should still be plenty of capacity left over to power a 3.3v antenna if it's jumper that way (the default, however, is 5v antenna power).

The only other question for that version is whether the preamp will be kept or not. We'll get the answer to that when the 2nd prototype boards arrive, probably early next week.