Is encryption allowed over this network? I know it’s not allowed over HAM. Also is triangulation / message source identification possible?

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aposm 8 hours ago | parent | next [-]

Yes, it is enabled by default (in fact this caused problems earlier on). Licensed hams (in the US) can increase transmit power (and theoretically use additional spectrum outside of ISM) but even the default "public" channel was encrypted with a known, publicized key. There was some debate whether this ran afoul of amateur radio rules against encryption, even if the key is known, since it cannot be disabled. I believe there was some progress in fixing this and allowing truly unencrypted channels for licensed operators, but I haven't checked back recently.

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NoiseBert69 6 hours ago | parent | prev | next [-]

On ISM frequencies encryption is allowed.

Triangulation will work as long as you transmit. But it will be difficult as LoRa works down to -145dBm which is an extremely weak signal.

	▲	colanderman 3 hours ago \| parent [-]
		I am pretty sure (though have not vetted) that triangulation of LoRa is possible even at very low SNR. The trick is understanding LoRa's trick, which is simply to "skew" the signal across time (via chirps), modulo a window of the configured bandwidth around the center frequency. The key is that the skew rate is purely a function of the spreading factor, bandwidth, and IQ polarity (= pol × BW² / 2^SF), so there's a small-ish finite number of skew rates. So you can just modulate raw IQ data with carriers at each of these skew rates to find one which gives you a bunch of carrier waves that hop around discretely at about twice the symbol rate, looking like an FSK signal. You can then bin this at a factor of, say 2^(SF-2) to correlate the signal and raise it up above the noise floor, on which you can apply any standard triangulation technique. I'll try vetting this soon and reply to this post with results.

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xanderlewis 7 hours ago | parent | prev [-]

Ham isn't an acronym. Just saying!