Comment by m4rtink

Yeah, our baloon was recorded by WSPR eeceivers thousands of kilometers away when it crossed the arctic circle for a day - we wpuld have no data if it were dependent on line of sight or even just flying over inhabited territory.

And indeed, the relions take minures to send a couple dozen bits of data. But the modulation is done in such a clever way, that it does not really matter - you know ehere the probe with your callsign was, how high, ground speed, temperature and panel volatage. There is quite agressive heuristics applied (eg. different precision for different altitudes as you don't really expect it to stay low for any ammount of time and survive, position via grid squares with course position still available even if you have incomplete data from a relation) so the few dozen bits are enough. :)

It is all super clever and hats off for those who developed this system. :)