Also known as: BT, Bluetooth Low Energy, BLE
Bluetooth is a short-range wireless standard for connecting devices over the 2.4 GHz band, used for audio, peripherals, and low-power links between nearby gadgets.1
Overview
Bluetooth forms small personal-area networks between paired devices — headphones to a phone, a keyboard to a laptop, a sensor to a hub — hopping rapidly across the crowded 2.4 GHz ISM band to dodge interference. The devices in one link form a piconet, with one central node coordinating the others, and the hopping pattern spreads their traffic thinly over the band so neighbours collide only briefly.
Bluetooth Low Energy (BLE) is a separate, power-frugal profile aimed at battery devices that wake, send a short burst, and sleep. That duty-cycled design has made it the backbone of many IoT sensors, beacons, and wearables, where a coin cell must last months or years. Classic Bluetooth, by contrast, keeps a continuous stream open for audio and file transfer.
Unlike Wi-Fi, Bluetooth targets close-range, low-bandwidth links rather than network access; for touch-range pairing, NFC is closer still. All three share the same congested unlicensed spectrum, so they are engineered to coexist rather than to reach far.
Classic vs Low Energy
The two flavours share a band and a name but are built for different jobs:
| Trait | Classic Bluetooth | Low Energy (BLE) |
|---|---|---|
| Aimed at | Audio, continuous streams | Sensors, bursts, beacons |
| Power draw | Higher | Very low (sleeps between bursts) |
| Data rate | Up to ~2–3 Mb/s | ~0.1–2 Mb/s |
| Connection | Held open | Brief, on demand |
| Typical use | Headphones, speakers | Wearables, IoT, tags |
Modern chips implement both, so one radio can stream music and also talk to a low-power fitness band.
Where it fits
Bluetooth is built for convenience over short distances at low power, not throughput, so it is rarely part of a GopherTrunk data path. Its relevance to an SDR user is as interference: the dense, hopping 2.4 GHz traffic from Bluetooth and Wi-Fi is exactly the kind of noisy spectrum one learns to recognize and avoid when siting an antenna, and a nearby BLE device can raise the noise floor a wideband receiver sees.