| In the UK, AM broadcasts are mainly on medium wave (MW), including BBC Radio 5 Live and local radio stations. Radio 4 goes out on MW and long wave (LW) as well as on FM. |
Most reception problems with AM radio are due to a weak signal or interference. Signals can travel long distances, but obstructions such as large buildings or hills may weaken them. Interference can come from a number of sources.
Time of day
AM reception can vary a great deal from day to night because of differences in the atmosphere. You may get good, clear reception during the day, but after sunset the signal may fade or become distorted. Signals travel further at night, so you may get interference from other transmitters, and you may even hear stations from outside the UK.
Buzzing, crackling and clicks
AM signals are prone to electrical interference from outdoor sources such as street lamps, flashing signs and power lines, which can cause crackling. Thunderstorms can also cause crackling. Clicks or buzzes can be caused by interference from a domestic appliance or faulty fridge or central heating thermostat. If you are not sure what is causing the interference, leave the radio on and then try switching off or disconnecting your appliances one at a time to see if there is an improvement.
Aerials
Portable radios usually have a built-in AM aerial, while hi-fi systems often have a plastic loop or wire that you need to connect.
AM aerials are directional, so you may need to turn the radio, loop or wire to get the best reception.
Careful tuning may find a stronger signal and help minimise interference.
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