Duty Cycle Rules
Edit on GitHubWhat transmit duty cycle is, the limits that apply in different regions, and how the beacon's schedule fits.
Duty Cycle Rules
Many regulators limit not just power but duty cycle: the fraction of time a device may transmit. A beacon that keys every 10 seconds must understand this.
What duty cycle is
Duty cycle = transmit time / total time, expressed as a percentage. A 1% duty cycle means the device transmits 1 second out of every 100.
Typical limits
| Region / service | Duty cycle limit |
|---|---|
| EU 433 MHz ISM | Often 1-10% depending on the specific harmonized standard |
| PMR446 | Voice-oriented; beaconing is not a defined use |
| 70 cm amateur | No hard duty cycle, but courtesy applies |
| US (no ISM at 433) | N/A for unlicensed; amateur rules apply |
The beacon’s schedule
At default settings (payload ~3 s, sleep 10 s), the beacon transmits about 20-25% of the time. That exceeds common ISM duty-cycle limits, which is another reason full-power operation generally requires a license.
Adjusting to comply
- Increase the sleep interval (e.g. 60 s): duty cycle drops to a few percent.
- Shorten the payload: fewer frequencies, no name/GPS, lower WPM.
- Use fewer repeats (repeat count 1 instead of 3).
The dashboard lever
The sleep interval slider (1-300 s) directly controls duty cycle. At 60 s sleep with a 3 s payload, duty cycle is about 5%; at 300 s, about 1%.
Emergency exception
In a genuine emergency, nobody will object to continuous transmission. The EMERGENCY mode ignores sleep entirely by design. The duty cycle discussion is about routine and testing use, not life-threatening situations.