[api]

Should we be looking for evidence of LoRA style transmissions for SETI? The energy required to get a loud conventional signal to go dozens or hundreds of light years is insane. But it seems like this kind of modulation might allow interstellar range with “only” gigawatt scale power levels.

It’d be an ideal way to create a signal with the potential to reach, say, a large fraction of the galaxy without requiring a Dyson swarm to power the transmitter.

Of course there are so many modulations this might be combinatorially impossible unless we can make some rational guesses about what a rational intelligence would use for interstellar communication if they wanted others to notice.

[wildzzz]

You get added again out of a spread spectrum signal and it helps with interference too but the main issue is that with the power spread out, it's much harder to detect at long distances. It becomes even harder to detect when you don't know the spreading sequence. You may "see" some RF power in the spectrum but without knowing the chip sequence, it might as well be noise. LoRa uses a type of spread spectrum method that is even harder to detect if you aren't expecting it. There's an example of someone using it for a 100km data link for an RC plane but you know what works at an even longer range? CW, aka Morse code, at low frequencies (1-30MHz). They can wrap around the earth even at relatively low power. LoRa is nice because it's modern and you can get nice data rates that are appropriate for machine-to-machine communications but spread spectrum waveforms will never be useful when you just want any signal to go as far as possible.