433 MHz

This is where a receiver should be pointed first, and it is where WaveShark opens. The devices here transmit on a schedule of their own, every few seconds to every few minutes, so covering the whole band continuously catches things a scan would miss by design.

Almost everything here carries a stable device id, which is what turns an afternoon of listening into a list of devices rather than a list of transmissions. A burst that nothing decodes is still kept, with its timings and bits sliced out, which is where reverse engineering starts.

In North America the equivalent traffic is largely on 315 MHz and 915 MHz, and tyre pressure sensors sit on 315 there.

$ waveshark --tune 433.92 --span 2400 --survey

What lives here

• ISM sensors and remotesAbout 130 device descriptions from the rtl_433 family: weather stations, thermometers, door contacts, gate remotes, security sensors and shelf labels.
• TPMSTyre pressure sensors as cars pass: the sensor id, the pressure, the temperature and whether the wheel is turning.