Default is `unset` which equates to `LONG_FAST`. Presets are pre-defined modem settings (Bandwidth, Spread Factor, and Coding Rate) which influence both message speed and range. The default will provide a strong mixture of speed and range, for most users.
The presets are designed to provide further options for optimizing either speed (and reduced network congestion) or range, which can be useful for two real world scenarios:
1. A high number of devices exist in the mesh, or messages are sent very frequently. Faster speeds (and therefore lower radio time per device) can help with mesh network congestion.
2. Maximum range is desired, for long range scenarios where a several second delay in message receipt is acceptable (for instance, attempting to send messages from a town to a distant mountain top).
8. `VERY_LONG_SLOW` (Slowest, lowest bandwidth, highest airtime, longest range. Not recommended for regular usage as does not form meshes well and is unreliable)
This setting controls the actual hardware frequency at which the radio transmits, represented by a frequency slot between 1 and NUM_SLOTS (the maximum for the current region and modem preset). If set to `0`/UNSET, the device reverts to the older channel name hash-based algorithm for determining the frequency slot.
For testing it is useful sometimes to force a node to never listen to particular other nodes (simulating radio out of range). All nodenums listed in the ignore_incoming array will have packets they send dropped on receive (by router.cpp)
Setting this to option to 'true' means the device will ignore any messages it receives via LoRa that came via MQTT somewhere along the path towards the device. Note this only works when your device and the MQTT node are running at least firmware version 2.2.19.
Setting this option to 'true' means the device will ignore the hourly duty cycle limit in Europe. This means that you might violate regulations if the device transmits too much. By default, this option is set to 'false,' which means the device will stop sending data when it reaches the hourly limit and will start again when it is allowed to do so.
This is an option specific to the SX126x chip series which allows the chip to consume a small amount of additional power to increase RX sensitivity.
### Override Frequency
This parameter is for advanced users and licensed HAM radio operators. When enabled, the channel calculation will be ignored, and the set frequency will be used instead (frequency_offset still applies). This will allow you to use out-of-band frequencies. Please respect your local laws and regulations. If you are a license HAM operator, make sure you enable HAM mode and turn off encryption.
Because the device will reboot after each command is sent via CLI, it is recommended when setting multiple values in a config section that commands be chained together as one.
```shell title="Example:"
meshtastic --set lora.region US --set lora.modem_preset LONG_FAST