Distortion on FM radio

This often appears as a fuzzy, gritty or scratchy sound.   It is commonly caused by the FM radio signals reflecting off objects or hillsides and reaching your radio by different paths. Its technical name is multipath distortion. It is often worst in hilly or heavily built-up areas. Indoor portables are especially susceptible.

         multipath1

Distorted sound can also occur if your radio is off-tune. This can increasingly happen if your batteries are beginning to fail.


What to do

  • Ensure your radio is correctly tuned in. Check that your batteries are in good condition, or use mains power.
  • If your radio is a portable, try moving the aerial to different angles. You could also try a different position in the room. Windowsills and high shelves are good places for radios; avoid putting them close to radiators or electronic equipment such as computers, mobile/cordless phones or TV sets.  
  • The telescopic aerial fitted to stereo portables is a compromise and the radio will often only give really good results if connected to an external aerial. If that's not possible, switch to mono as it will usually sound better.
  • If you are using an FM tuner as part of a HiFi system, check your aerial: it may be broken or pointing in the wrong direction, or the cable may be broken or loose. Even loft aerials can suffer corrosion, especially at the connecting terminals.
  • We do not recommend the use of ‘ribbon'-type indoor aerials for FM reception as they are highly susceptible to multipath distortion. An outdoor, or even a loft aerial, is better provided it is a directional and not omni-directional type.
  • Make sure you are tuned to the best frequency for your area, as you can often pick up more than one signal. You can find out more by visiting the download links on this page FM Radio

*For help with aerials we would recommend using a professional installer. We cannot recommend individual installers but you may wish to seek advice from a recognised industry body, such as the Confederation of Aerial Industries (CAI).

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