Need help picking us up on your radio? Hopefully this information can help.

Good radio reception is dependent on the type of radio receiver, the type of antenna and the signal strength at the listener’s location. Signal strength can vary greatly with the distance from the radio transmitter and physical location of the listening environment being key factors. Geographic locations such as built up, wooded or hilly areas have great influence over received signal strength. And it also helps if you live within the licensed broadcast area of the station.

Reception quality changes significantly between small cheap portable radios and the more expensive hifi systems. Car radios generally offer good reception as well.

The FM antenna is the most important factor in achieving good reception. Many radio reception difficulties are caused by deficiencies in the radio or antenna installation. Interference or obstruction of a radio signal to the antenna should be kept to a minimum. The antenna should always be placed away from electrical devices such as computers, refrigerators, power tools or in house wiring. If an external antenna used, then the antenna should point in the direction of the transmitter and be positioned to minimise the effect of obstructions such as trees and buildings.

COMMON FM RADIO RECEPTION PROBLEMS

Hissing

If your radio hisses it could be because it is receiving a weak signal.
This happens because radio receivers need reasonably strong signals to decode the stereo component of an FM signal. A weak signal can be caused if you are too far from a transmitter as well as large buildings or hills blocking the signal path.

A good quality VHF Band 2 outdoor antenna correctly positioned to pick up the best signal will usually always improve FM reception. If necessary, a VHF Band 2 amplifier can be fitted to the antenna to boost a weak signal as well.

If the radio is portable with no provision for plugging in an external aerial, listeners should try adjusting the position of the radio’s own antenna to improve the reception. Alternatively, moving the receiver to somewhere else in the room may help particularly as FM reception can vary a great deal over short distances. Radio reception is often better near windows or upstairs rather than downstairs.

Distorted “S” Sounds on FM Radio

This phenomenon is known as “Multi-path Distortion.” Multi-path distortion is characterised by sibilance which is the distortion of ’s’ and ‘z’ sounds used in speech to ‘shhhhh’ sounds. It is caused by the transmitted signal traveling to the listener’s radio receiver by more than one path. This is usually caused by the signal being reflected off hills or tall buildings. The reflected signal arrives at the receiving antenna a moment later than the direct signal because it has traveled further. The reflected and direct signals then interfere with each other causing the distortion.

The best way to minimise multi-path distortion is to use a directional rooftop FM antenna which will only pick up signals coming directly from the transmitter and reject signals that arrive at the back or side of the antenna. It is also sometimes possible to mount the antenna so that a building screens it from the reflections but not from the wanted signal. If multi-path distortion is affecting a portable FM radio, try moving it to a different position in the room.

Adjacent FM Channels

Adjacent channel interference is caused by an FM station which is close in frequency to the station being listened to. It can sound like a twittering noise in the background. This problem is usually only apparent on FM stereo but if the interfering station is very close in frequency, ie. only 50 or 100 kHz away, the effect may also be heard in mono.

GETTING THE BEST FM RADIO RECEPTION AT HOME OR WORK

• Make sure the antenna is suitable for receiving FM radio and is pointing in the direction of the radio transmitter at Mount Wellington in Hobart.

• Check that the antenna cable and connections are in good condition.

• If possible swap another radio for the affected one. If the radio reception improves, there is likely to be an equipment problem with the first radio - check the antenna.

• Sometimes the TV antenna is used for both the TV and FM radio. If this is the case, remove the TV connection leaving only the direct cable between the antenna and radio.

Listeners should also note that FM radio signals travel in almost straight lines and are unable to travel over or penetrate large obstructions. This usually means that parts of a coverage area may have a weak signal particularly in hilly terrain or highly built up urban areas.

FM Dipole Antenna

The FM dipole antenna is economical and relatively simple to install, whilst offering a considerable increase in reception quality. An FM dipole antenna is built from TV ribbon cable, which is often supplied with hi-fi tuners or can be purchased from an electronics store.

The length of the dipole antenna should be approximately 1.5m long and is constructed by connecting the ribbon cable to the radio receiver. The dipole antenna can be erected by attaching the cable to a wall with the 1.5m section of the cable positioned horizontally where the best signal is found. This antenna can be rotated to find the best position to further optimise reception.

External FM Antenna

The best quality FM radio receiver system consists of an FM antenna, permanently erected externally. As FM radio signals occupy the same frequency band as some VHF television signals an FM antenna is very much like a VHF television antenna. A VHF television antenna designed to receive Band 2 TV channels may be used to improve FM radio reception.

A professional antenna installer can split the cable from the TV antenna and then run separate cables to the TV and FM receivers. If a splitter device is used, the signal strength is reduced. In some cases, particularly in low signal strength areas, an amplifier may also be needed. An amplifier boosts the signal and ensures that adequate signal strengths are supplied to both the radio and the television set.

GETTING THE BEST FROM YOUR CAR RADIO

The metal bodywork of a vehicle prevents signals reaching the radio, so a quality external antenna is needed for good reception.

FM radio reception can be difficult when traveling in built-up areas or in undulating terrain. Multi-path distortion or a weak signals may be experienced. However, FM radio generally gives good results with quality sound and the option for stereo reception.

Interference

Car radios should be relatively immune to ignition and other electrical interference from the vehicle, but failure of the vehicle’s electronic suppression equipment can cause crackles and interference or:

• Rhythmic ticking varying with engine speed
• Whining varying in pitch with engine speed
• Regular crackling associated with a car heater or the windscreen wipers/washers
In most cases, a reputable auto electrician can fix this sort of interference.

Car Antennas

Car radio antennas are always located externally and are usually a telescopic rod, although there are a number of cars fitted with heated rear window antennas or stubby helical wound antennas. To get the best from a car radio:

• The antennas should be as high as possible, preferably on the roof and away from the engine
• Telescopic antennas should be fully extended
• The antenna should not be folded back onto the roof and kept well clear of the bodywork
• Antennas should be of the correct length - around 80 cm is ideal. Antennas much shorter or longer than this may provide inferior results