What's wrong with my radio reception? | ACMA

What's wrong with my radio reception?

It’s not just your TV that can have signal problems—your radio can also be affected. Disturbance to your radio can be due to either poor reception or interference.

The causes and solutions for poor reception and interference problems are different. The following information may help you to discover what’s causing your problem and how to fix it.

Poor reception

If you’re receiving fortuitous radio signals—those that aren’t actually planned to serve your area—you’re more likely to experience disturbance. This is because weaker and more distant signals are less reliable.

Even though you may be located in a particular coverage area, other factors can also affect the quality of your radio reception. These can include a tall building or trees situated between you and the transmitter, or the quality of your antenna and cables.

Try moving the aerial or the radio itself, or use an outside antenna, to see if your reception improves.

Weak radio signals are also more likely to be affected by nearby low-level interference sources.

Interference

Interference can affect radio frequencies in different ways, so there is specific information for AM radio, FM radio and digital radio. Read the relevant section below for your type of radio.

AM radio 

AM radio is very susceptible to interference, but a large percentage of reception difficulties are because of faults or deficiencies in radio receivers. You should first make every possible effort to determine the reliability of your radio.

A very effective and simple method of checking your radio’s reliability is to test another one in its place. If the second radio has the same problem (particularly if it is battery-operated and independent of the mains voltage), it is reasonable to assume that the problem is interference.

Various sources can cause interference to AM radio reception. The major sources of degraded reception include interference from electrical appliances, power lines and street lighting:

  • Electrical appliance interference—Many common electrical appliances can cause interference to your AM radio reception. To locate the source of interference, note the pattern of occurrence and switch your appliances on and off to see if your reception improves.
  • Electric motor interference—appliances like food mixers, power tools, sewing machines, electric shavers, vacuum cleaners and hair dryers can cause electric motor interference. This causes a whine or buzz in the radio that varies in pitch with the speed of the motor in the appliance. It can be readily identified because it only occurs when an appliance is used.
  • Thermostat interference—appliances like hot water systems, refrigerators, waterbed heaters, fish tank water heaters, and swimming pool and spa bath chlorinators can cause thermostat interference. This can generally be identified by a harsh buzz that occurs for a regular period of time and is repeated often.

WARNING: Under no circumstances should you attempt to repair or modify any electrical equipment unless you are qualified to do so. Always leave this to the experts!

  • Power line interference—this is normally heard as a harsh, rasping buzz that affects both mains- and battery-operated radios. It can often affect a large number of homes. The interference most commonly occurs during hot, dry and windy weather when it is generated by sparking between insulators and metal-securing brackets. A similar problem occurs in the evenings as dew forms on built-up dust, salt or industrial pollution that has collected on the insulators and brackets of the power line, again causing sparking. In both instances, the interference generally clears after rainfall. If the interference continues after rain, it may indicate physical damage to the power line.
    • What to do—eliminate the possibility that electrical appliances are causing the problem. Then report persistent power line interference to your electricity provider—it is their responsibility to rectify the problem.
  • Street lighting interference—like power line interference, this will generally affect a large number of homes. The interference starts when the street lighting turns on or coincides with it flashing on and off during the day or night.
    • What to do—report the problem to your electricity provider.

WARNING: Do not attempt to rectify any suspected faults on power poles, power lines or street lighting. Contact your local electricity supply authority if problems occur with power or lighting utilities.

FM radio

FM signals are more immune to interference and so provide better quality reception than AM. If you do experience problems, the cause is possibly a fault within the FM radio receiver or deficiencies within your entertainment system.

Good FM radio reception generally depends on using an appropriate outdoor antenna. The antenna should be installed correctly, be connected to the radio receiver with good quality coaxial cable and point towards the FM transmitter station.

A very effective and simple way to check the reliability of your FM radio is to test another one in its place. If the problem no longer exists, you can assume that the original radio receiver has a fault.

Common interference problems on FM radio include:

  • Multipath reception—sharp or harsh sibilance (audio distortion) to the reproduced sound, often accompanied by the ‘stereo light’ flashing on the FM radio receiver. This occurs when the transmitted FM signal is received over two or more paths—a direct signal from the FM transmitting station and at least one reflected signal coming from a large reflective body such as a mountain, hill or building in the area.
    • What to do—if you’re not using an outdoor antenna, you should install one. If the problem continues, carefully check the direction the antenna is pointing. Finely adjust the direction for the best quality radio reception.
  • Aviation transmitter interference—this can occur if the FM radio receiver cannot reject unwanted signals.
    • What to do—a simple filter can be installed in the radio to suppress the unwanted signals. This modification should be carried out by a qualified service technician.
  • Two-way radio interference—both FM and AM radio receivers can sometimes pick up unwanted transmissions from two-way radio, CB and amateur radio services. Hearing voices other than those on the radio program you want to listen to identifies this form of interference. Very often, the problem arises because the broadcast radio receiver cannot reject the operating frequencies used by CB, amateur or two-way radio transmissions.
    • What to do—check out this page for more information about two-way radios.

Digital radio

Digital radio (DAB) reception is less prone to interference than AM and FM radio.

A common cause of interference to DAB reception is impulse noise (short high-energy bursts of wideband noise) emitted from domestic electrical appliances in or outside the home. The best way to identify interference in your home or neighbourhood is to eliminate possible problem items by turning them off one at a time, until it disappears. Potential sources are:

  • microwave ovens
  • LED lighting
  • computers and their uninterruptible power supply (UPS), which allows a computer to keep running for a short time when the main power supply is lost
  • TVs.

Sometimes moving the aerial or the radio, or using an outside aerial, may help to improve your reception. 

Help is here!

If your radio reception is affected by external interference you can seek help from the ACMA. External interference does not occur in your home or premises, and is beyond your ability to control.

Last updated: 25 January 2017