Radio Duty Cycle

The radio duty cycle is the proportion of time a transmitter is allowed to be actively sending on a given frequency, expressed as a percentage of any one-hour window. It is primarily a regulatory limit, not a hardware one: regional authorities cap duty cycle in the shared, licence-free ISM bands so that no single device can hog the airwaves and so everyone gets fair access to a finite, unlicensed resource.

Why it constrains off-grid mesh

For LoRa and Meshtastic operators, duty cycle is often the real ceiling on how much data a node can move — more so than raw bandwidth. In Europe the 868 MHz band imposes a strict 1% duty cycle on most sub-bands, meaning a node may transmit only ~36 seconds per hour. North America's 915 MHz band instead limits dwell time per channel (e.g. 400 ms) with frequency-hopping rather than a flat duty-cycle percentage, which is more permissive. Because higher LoRa spreading factors lengthen each packet's airtime, they consume the duty-cycle budget far faster, forcing a trade between range and message rate.

Designing within the budget

Sovereign builders plan around the cap by keeping payloads small, lowering beacon frequency, and choosing the lowest spreading factor a link's SNR allows. Exceeding the legal duty cycle is both unlawful and antisocial — it raises the noise floor for every other node sharing the band.

Always flash firmware to your correct regional setting so the duty-cycle/dwell rules match your jurisdiction. See the ISM band entry for the spectrum these limits govern and hop limit for the mesh-side airtime control.