Is Meshtastic legal where you live?

Europe: EU_868

The EU_868 region uses 869.4 to 869.65 MHz. Regulators give these terms for that sub-band:

• Germany (Bundesnetzagentur Vfg. 91/2025, band 54): 500 mW ERP, duty cycle up to 10%, or alternatively access techniques that avoid interference.
• Czech Republic (CTU, band g7): 500 mW e.r.p., 25 kHz channel, duty cycle "Paragraph 7 or 10%".
• Poland: the 2022 regulation points to EU/CEPT decisions. An older 2011 regulation lists 500 mW e.r.p. and 10% or listen-before-talk. The annex parameters are only partly confirmed here, so assume the harmonised 500 mW and 10% and check the current UKE regulation.
• UK: an older statutory instrument lists 500 mW ERP and 10%. Check the current Ofcom interface requirement IR 2030 before relying on it.
• France, Italy, Netherlands, Austria: national texts are not checked here; the EU harmonised band is 500 mW ERP and 10%.
• Spain, Switzerland: check the national regulator (CNAF in Spain, BAKOM/OFCOM in Switzerland); both follow the CEPT short-range device framework.

Duty cycle is measured over one hour. Ten percent means a radio may transmit for at most six minutes per hour in total. The firmware enforces this in EU regions. The setting override_duty_cycle ignores the limit and "may violate regulations" according to the docs, so leave it off.

The ERP trap: antennas and power

The limit is ERP, effective radiated power, so antenna gain counts. ERP measures gain against a half-wave dipole, so subtract 2.15 from an antenna's dBi figure: a 22 dBm radio with a 5 dBi antenna radiates about 22 + 5 - 2.15 = 24.85 dBm ERP, inside the limit. A radio set to 27 dBm with a 3 dBi antenna already reaches about 27.85 dBm ERP, over the 27 dBm line, unless cable loss eats the difference. Fitting a bigger antenna on a board that already transmits at the limit puts you over it. Read the antenna guide before upgrading, and note that tx_power 0 means the default maximum legal continuous power in the firmware, not your national limit.

United States

47 CFR 15.247 covers 902 to 928 MHz. It allows up to 1 W (30 dBm) peak conducted output for digital modulation, and antenna gain above 6 dBi must reduce conducted power dB-for-dB, with exceptions for some fixed point-to-point links. Part 15.247 has no duty-cycle limit.

Other regions

The firmware's region limits are ceilings, not national laws. See frequencies by country for the table. For any other country, check your national regulator.

Encryption and ham radio

On licence-free bands, encryption is fine. Amateur radio rules are different: FCC Part 97 forbids obscuring the meaning of messages on amateur frequencies. Meshtastic's licensed (ham) mode therefore sends everything unencrypted and signs packets. Use it only if you hold a licence, and only on amateur regions (ITU_*_2M/70CM). Licensed and normal nodes are not interoperable on private channels. Amateur power limits differ by country and licence class: check them with your licensing authority.

Is it legal to use other people's nodes and the public mesh?

Receiving and relaying messages on a licence-free band is the normal operation of the system, and the Meshtastic introduction states that LoRa can be used without the licences or certifications amateur radio requires. What you send is still your responsibility, and national law on content applies as it does to any messaging service. The default channel key is public, so anything on it can be read by anyone with a radio, as the encryption guide explains.

Practical checklist

1. Set the region that matches your country.
2. Keep antenna gain and cable loss in mind when you compute ERP.
3. Leave duty-cycle override off in Europe.
4. Do not use ham mode without a licence.