Mode Bluetooth LE

Bluetooth LE: the advertising packets devices broadcast openly.

Group	IoT & sensors
Default frequency	2402 MHz
Default sample rate	4 Msps
In the mode list	Advertising, 2.4 GHz

Step-by-step: Tutorial-Bluetooth-LE

What Bluetooth LE is

Bluetooth Low Energy devices announce themselves in advertising packets on channels 37, 38 and 39. OnAir lists them like a scanner app, and never connects or pairs.

Frequencies and settings

Advertising on channels 37, 38 and 39 (2402 / 2426 / 2480 MHz), one at a time or hopping, 4 Msps.

Setting	Value
Start frequency	2402 MHz
Tuning range of the mode table	2400 to 2484 MHz
Sample rate asked	4 Msps
Lowest working rate	4 Msps
Channel width	2 MHz

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 Advertising, 2.4 GHz.

What OnAir shows

What a scanner app such as nRF Connect shows: a device table with address type, name, level history, vendor, services, iBeacon, Eddystone and exposure notification beacons, and a packet log. Receive only: it never connects, pairs or transmits and does not follow connections; most phones use random addresses that change every few minutes for privacy.

The mode's own tab has these screens: Devices, Packets. The other tabs (Overview, Receiver, Scan, History) are described on the Main window page.

Tips and caveats

• Checked with generated signals and impairments; recordings of real signals welcome.
• Which radio: No: this mode needs a radio that samples at 4 Msps or more, and an RTL-SDR reaches about 2.4 Msps.
• Try it without a radio: most modes include a built-in synthetic test signal, so you can open the screen and try the controls first.
• Receiving and the law: This mode is passive. It only receives, never connects, pairs or joins networks, and never decrypts payloads. Check the rules where you live. See Legal.

Related pages

• All modes, IoT & sensors
• Supported radios, Troubleshooting, FAQ
• More in IoT & sensors: ISM sensors, LoRaWAN, Meshtastic, MeshCore, Zigbee / 802.15.4, Wi-Fi HaLow (802.11ah), ANT+ sensors, DECT cordless phones, Wi-SUN FAN, LoRa (raw), Wi-Fi networks