LoRa is a low-power, long-range modulation that encodes data as chirps —
frequency sweeps that ramp across the channel. Chirp spread spectrum gives LoRa
excellent sensitivity (it decodes well below the noise floor),
making it popular for low-rate IoT telemetry in ISM bands.1
LoRa encodes symbols as rising frequency chirps; the diagonal sweeps are its waterfall signature.
Overview
A receiver “de-chirps” by multiplying with a reference sweep, collapsing each chirp to a
tone whose frequency encodes the symbol. LoRa is unrelated to the trunked-voice systems
GopherTrunk targets, but is a common sight on the waterfall
in the 433/868/915 MHz ISM bands.
Sources
LoRa — Wikipedia, for the chirp-spread-spectrum modulation, its sensitivity, and ISM-band use. ↩
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