LoRa
A long-range, very low-data-rate radio that can reach kilometres on a small battery.
LoRa is a chirp spread-spectrum modulation in sub-GHz license-free bands; its spreading factor trades data rate for range, and regional rules limit airtime.
Examples
Sending 12 bytes takes about 41 ms at SF7 and over a second at SF12, at 125 kHz.
LoRa uses licence-free bands: 868 MHz in Europe, 915 MHz in the Americas.
See also