[jasonwatkinspdx]

> Sadly I think the actual antenna and hardware were relatively large since it's a long wave signal, but maybe with SDR it'll all fit on the head of a pin these days.

Unfortunately there's no real way to cheat physics as far as shrinking a wavelength goes. With RF antennas about the best you can do is a major dimension 1/10th the frequency of interest.

[namibj]

There are many DCF77 receivers in Germany that are contained in a square box that's barely large enough for a AA battery; the rest of the square contains the motor/gears and the electronics/receiver (incl. a ferrite loopstick antenna).

The wavelength is around 3.8km...

[jasonwatkinspdx]

Yeah, that's because it's receiving an extremely narrowband signal accumulated over a long window so it can suffer the trash efficiency I'm talking about.