Play this concept: spreading factor

Slide the spreading factor (SF). Watch how far the signal can reach and how long it stays on the air.

Spreading factor SF9

Payload 20 bytes

—Approx. range (open ground)

—Time on air

1% duty-cycle budget36 s per hour

Teaching model: EU868, 125 kHz, coding rate 4/5, 8-symbol preamble, CRC on. Time on air uses the Semtech formula. Range is illustrative: sensitivity per SF with a simple path-loss model (14 dBm, 2 dBi antennas, exponent 2.7). Real range depends on buildings and antennas.

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