OnAirDecode LoRa (raw) with an SDR
LoRa (raw): point-to-point LoRa frames as hex and text, SF / bandwidth set or searched (receive only, no decryption).
- Group
- IoT & sensors
- Start frequency
- 868.1 MHz
- In the mode list
- IoT, sub-GHz
What LoRa (raw) is
LoRa is a chirp-spread-spectrum radio used for point-to-point links and IoT. This mode shows plain LoRa frames between two radios: not LoRaWAN and not a mesh.
Frequencies and settings
Plain point-to-point LoRa (not LoRaWAN, not a mesh) on 433, 868 and 915 MHz (and any frequency you type; 137 MHz to 2.5 GHz is what a typical radio reaches), SF5 - SF12, 125 / 250 / 500 kHz, from 1 Msps (an RTL-SDR works).
| Start frequency | 868.1 MHz |
|---|---|
| Tuning range of the mode table | 137 to 2500 MHz |
| Sample rate asked | 2 Msps |
| Lowest working rate | 1 Msps |
| Channel width | 250 kHz |
OnAir takes any frequency you type; the numbers above are the mode's starting point and the range its table describes. In the app the shortcut label is IoT, sub-GHz.
What OnAir shows
Every frame as bytes (hex and text) with SNR, level, carrier offset and time. You set the spreading factor, bandwidth, header mode (explicit, or implicit with coding rate, CRC and length), sync word and frequency (EU868, US915, 433 presets), or leave spreading factor and bandwidth on Auto and every combination is searched. Receive only: nothing is sent, decrypted or interpreted, the payload is just the bytes.
The mode's own tab has these views: Frames, Settings, Decoders. The other tabs (Overview, Receiver, Scan, History) are described on the main window page.
Limits and what it was checked with
Checked with generated signals and impairments; recordings of real signals welcome.
Which radio you need
This is a shortwave mode, so the radio has to tune HF. An SDRplay, Airspy HF+ or an RTL-SDR in direct-sampling mode do that directly; with a HackRF an HF upconverter or a direct-sampling receiver is the usual route. A long wire or loop antenna matters more than the radio.
Receiving and the law
Questions about LoRa (raw)
Can I decode LoRa (raw) with an RTL-SDR?
An RTL-SDR can receive HF only in direct-sampling mode, which OnAir offers in its radio settings; results depend on the antenna. SDRplay and Airspy HF+ radios are better suited.
Is it legal to receive LoRa (raw)?
This mode is passive. It only receives, never connects, pairs or joins networks, and never decrypts payloads. Check the rules where you live.
Can I try LoRa (raw) in OnAir without a radio?
Yes. Most modes include a built-in synthetic test signal, so you can open the screen and try the controls before you own a radio.