My favorite place to check the time is https://time.is/
It has the handy feature of telling you if your system clock is set correctly, and if not how far it's off. Also, gets accurate time for any timezone.
Thanks! Yeah, spending $20 for US shipping is the thing I wanted to avoid. I'll try my luck with ebay again, and if it doesn't get here in time that's probably okay :)
I've got a possibly-oddball question:
I soldered the sma connector to the board, but due to some shipping issues I don't know if I can get an proper antenna before the next launch. What are the odds that a 2.4GHz wifi antenna on the receiver (plus stick on the transmitter) would be good to...