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When setting up a LoRa transceiver such as RNode, you will need to know what frequency it should transmit on and a few other parameters that will drastically change how the transceiver operates.cite-ref-0-1-0[1]

• Frequency

• Bandwidth (BW)

• Spreading Factor (SF)

• Coding Rate (CR)

• Transmit Power (TX)

Frequency, Bandwidth and Spreading Factor all need to match for nodes to communicate, while Coding Rate and Transmit Power may differ.

The LoRa Bitrate & Sensitivity Calculator can be used to explore how these parameters affect data rate, sensitivity and link budget.

• Parameters

• Frequency

• Bandwidth

• Spreading Factor

• Coding Rate

• Transmit Power

• Choosing frequency and bandwidth

• See also

• References

• External links

It is somewhat arbitrary, but can be chosen based on context-specific factors like local radio interference, existing use by other LoRa platforms, available antenna sizes, propagation characteristics and local regulations. LoRa RNodes typically operate on 433 MHz, 868 MHz or 915 MHz bands.

LoRa can be configured to use bandwidths in pre-determined steps from 7.8 kHz to 500 kHz in the sub-gigahertz bands, and from 250 kHz to 1.6 MHz in the 2.4 GHz band. Generally speaking, choosing a narrower bandwidth will result in a slower transfer rate but improved range. Conversely, choosing a wider bandwidth will result in an increased data rate but a shorter range.cite-ref-0-1-1[1]

Controls how spread out in time each data bit is. If a higher spreading factor is selected, each payload data bit will be spread out over more LoRa "symbols". LoRa can be configured for spreading factors between 5 and 12, although only 6 through 12 are accessible in the sub-gigahertz band, and 6 often requires a TCXO to be stable.cite-ref-0-1-2[1]

Controls the ratio of actual data to total transmitted data, the remaining bits being used for error correction. A higher coding rate (more error correction bits) slows down speed of data exchange and slightly increases power consumption, but makes communication more reliable. This is especially important when there is a lot of radio interference at the frequency being used. LoRa can be configured for four different coding rates: 4:5, 4:6, 4:7 and 4:8, with 4:5 being the lowest (least error correction) and 4:8 being the highest (most error correction).

Configuring LoRa transceivers with different coding rates might be useful if one receiver is located in an area with high amounts of interference but the other end of the link is not. In such a case, the two transceivers can be configured with asymmetric coding rates, such that optimal transfer rates can be achieved, even though interference levels vary at the different sites.cite-ref-0-1-3[1]

Higher levels will transmit further, be easier for anyone to detect and locate, will consume more power, and can cause overload problems if two nodes are right next to each other and transmitting at high power. Higher power levels are also more likely to be regulated. The maximum level varies by LoRa device.

It's important to make sure that your chosen frequency and bandwidth won't interfere with other users of the radio frequency spectrum, such as MeshCore, Meshtastic and LoRaWAN. To do so, calculate the lower and upper ends of the slice of the spectrum used by each (in your area) and make sure they don't overlap. The frequency is the center of the slice of the spectrum and the bandwidth is the total width of the slice. To get the lower value, you simply substract half the bandwidth from the center frequency, and to get the upper value you add half the bandwidth to the center frequency.

Note: Radio frequency spectrum is a legally controlled resource, and legislation varies widely around the world. It is your responsibility to be aware of any relevant regulation for your location, and to make decisions accordingly.cite-ref-2[2]

• Popular RNode settings

cite-note-0-11. ↑ https://unsigned.io/understanding-lora-parameters/ (CC BY-NC-SA 4.0)

cite-note-22. ↑ https://reticulum.network/manual/interfaces.html#rnode-lora-interface

• LoRa Bitrate & Sensitivity Calculator