Well, this is an unexpected advance:
https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.15.014053
It's basically a universal radio, picking up all frequencies at once, up through the more useful microwave bands (though this prototype doesn't quite get to the highest 5G band).
Even though it's based on quantum effects, it's likely going to be able to be miniaturized as it doesn't require extreme cold or anything exotic.
Does this method work for sending messages as well?
@SwindlerOfInsanity I'm pretty sure it doesn't.
Are you envisioning sending across all the spectrum at the same time?
@SwindlerOfInsanity It would be the most valuable if you could simultaneously broadcast different messages across the whole spectrum, using the same device.
Then it could be used to maximize bandwidth use.
Or as an ECM jammer...
@urusan Well at first I was thinking selective frequencys. But simultaneous thransmission could be intresting too. Who knows what might hear us if we started screeming into the void.