AM, which stands for Amplitude Modulation (AM) is the oldest radio broadcasting system in the UK. The term AM is commonly used to cover both Medium Wave (MW) and Long Wave (LW). All AM radio stations broadcast in mono.
The BBC broadcasts various radio services on AM, including Radio 5 Live and many local and nations radio services. It only broadcasts Radio 4 on LW.
Receiving MW and LW services
All AM radio services are broadcast in mono and, unlike FM services, they do not carry travel or programme information.
MW and LW aerials
If you are using a portable radio, you do not need to extend the telescopic aerial, as that is only for FM services. For AM and LW the aerial is normally built in to the radio itself. To improve reception, the whole radio needs to be rotated to get the best signal. If you have a hi-fi, wire loop aerials can normally be attached.
Owing to the physics of how AM signals travel, reception is often worse at night.