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Radio Settings

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Meshtastic is not LoRaWAN, Helium or TTN (TheThingsNetwork). Meshtastic uses the full spectrum frequency range designated to LoRa technology per region. This allows for several hundred possible frequency channels in the US region alone.

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Power limits will generally be lifted in the software if is_licensed is set to true. See HAM Mode for more information.

Europe Frequency Bandsโ€‹

433 MHzโ€‹

The maximum power allowed for Europe is +14 dBm ERP (Effective Radiated Power).

The band range is from 433 to 434 MHz.

There are four channels defined with the standard radio preset LongFast. After factory reset the radio will be set to channel 3 with a center frequency of 433.875 MHz.

868 MHzโ€‹

The maximum power allowed for Europe is +27 dBm ERP (Effective Radiated Power).

The band range is from 869.40 to 869.65 MHz. This is less than the 863โ€“870 MHz range defined as SRD Band, but allows for a higher ERP and a duty cycle of 10%.

There is one channel defined with the standard radio preset LongFast. After factory reset the radio will be set to channel 0 with a center frequency of 869.525 MHz.

North America Frequency Bandsโ€‹

915 MHz (ISM Band)โ€‹

The maximum output power for North America is +30 dBm ERP (Effective Radiated Power).

The band range is from 902 to 928 MHz.

There are 104 channels defined with the standard radio preset LongFast. After factory reset the radio will be set to channel 19 with a center frequency of 906.875 MHz.

Data Ratesโ€‹

Considerationsโ€‹

Various data-rate options are available when configuring a channel and are inversely proportional to the theoretical range of the devices.

  • Spreading Factor - How much we "spread" our data over time.
    • Each step up in Spreading Factor doubles the airtime to transmit.
    • Each step up in Spreading Factor adds about 2.5db extra link budget.
  • Bandwidth - How big of a slice of the spectrum we use.
    • Each doubling of the bandwidth is almost 3db less link budget.
    • Bandwidths less than 31 may be unstable unless you have a high quality Crystal Oscillator.
  • Coding Rate - How much redundancy we encode to resist noise.
    • Increasing coding rate increases reliability while decreasing data-rate.
    • 4/5 - 1.25x overhead
    • 4/6 - 1.5x overhead
    • 4/7 - 1.75x overhead
    • 4/8 - 2x overhead

Predefined Channelsโ€‹

We have six predefined channels. These are the most common settings and have been proven to work well:

Channel settingAlt Channel NameData-RateSF / SymbolsCoding RateBandwidthLink Budget
Short Range / FastShort Fast6.8 kbps7 / 1284/8250137dB
Short Range / SlowShort Slow3.9 kbps8 / 2564/8250140dB
Medium Range / FastMedium Fast2.2 kbps9 / 5124/8250143dB
Medium Range / SlowMedium Slow1.2 kbps10 / 10244/8250146dB
Long Range / FastLong Fast0.67 kbps (default)11 / 20484/8250148.5dB
Long Range / SlowLong Slow0.18 kbps12 / 40964/8125154dB
Very Long Range - SlowVery Long Slow0.05 kbps12 / 40964/831.25160.1dB
note

The link budget used by these calculations assumes a transmit power of 17dBm and an antenna with 0dB gain. Adjust your link budget assumptions based on your actual devices. Data-rate in this table is actual measured but doesn't count mesh overhead, hops and re-transmissions.

Custom Settingsโ€‹

You may want to select other channels for your usage. The other settings can be set by using the Python API.

meshtastic --ch-set spread_factor 10 --ch-set coding_rate 4 --ch-set bandwidth 125 --ch-index 0

After applying the settings, you will need to restart the device. After your device is restarted, it will generate a new crypto key and you will need to share the newly generated QR Code or URL to all your other devices.

Some example settings:

Data-rateSF / SymbolsCoding RateBandwidthLink BudgetNote
37.50 kbps6 / 644/5500129dBFastest possible speed
3.125 kbps8 / 2564/5125143dB
1.953 kbps8 / 2564/8125143dB
1.343 kbps11 / 20484/8500145dB
1.099 kbps9 / 5124/8125146dB
0.814 kbps10 / 10244/6125149dB
0.610 kbps10 / 10244/8125149dB
0.488 kbps11 / 20484/6125152dB
0.336 kbps11 / 20484/8125152dB
0.073 kbps12 / 40964/531160dBTwice the range and/or coverage of "Long Slow", low resilience to noise
0.046 kbps12 / 40964/831160dBTwice the range and/or coverage of "Long Slow", high resilience to noise

The link budget used by these calculations assumes a transmit power of 17dBm and an antenna with 0dB gain. Adjust your link budget assumptions based on your actual devices.

These channel settings may have not been tested. Use at your own discretion. Share on https://meshtastic.discourse.group with your successes or failure.

Cryptographyโ€‹

The pre-shared key (PSK) used by the devices can be modified.

  • 0 = No crypto
  • 1 = Default channel key
  • 2 - 10 = The default channel key, except with 1 through 9 added to the last byte

Use of cryptography can also be modified. To disable cryptography (maybe useful if you have Ham radio license):

meshtastic --setchan psk 0