UK DOMESTIC SERVICES are broadcast across three wavebands, FM (or VHF) and Medium Wave (often referred to as 'AM' , though that term also includes 'Long' and 'Short' Waves). Long Wave is also used by BBC Radio 4. Other European services can to some extent be received over most of the country, but not generally on FM. Nearly all radio sets offer FM and MW, with most covering all three bands, and a few also cover the 'Short Waves', which can receive international broadcasts. However, relatively few services are now broadcast on both FM and MW, so it is essential to receive all wavebands clearly.
The FM band
In the UK this extends in frequency from 87.5 MHz to 108
MHz. FM is divided into sub-bands, used, with some exceptions, as follows:
For FM reception
Within a transmitter's service area, it is usually practical to receive a reasonable signal indoors on a mono portable, or a portable with two speakers, if switched to 'mono'; closer to the transmitter, a reasonable stereo service may be available. Try positioning the radio at different points in a room: generally, the higher the better and near a window. Nearly all portable radios have a telescopic rod aerial, which should be extended and tried at different angles. Good reception is not only a matter of a reasonably strong signal, but also of rejecting interference.
To obtain high-quality stereo, an external fixed aerial will often be necessary. This can be placed in the loft if all the wanted signals are quite strong. In blocks of flats, an aerial-fed distribution system may already be available with an outlet marked 'FM' or 'VHF' (not 'TV'). The aerial cable should be connected to the socket or terminals, labelled 'FM', on the radio or hi-fi tuner.
Some signals are 'vertically polarised', in which case the aerial needs to be placed with its elements vertical. Most but not all signals also have a horizontal component; if all the stations you want to receive have this, then aligning the aerial elements horizontally may help to reject interference. It is best to try out different aerial locations and orientations with all the services to be received, to arrive at the best compromise.
Cable TV / telephone companies usually supply a range of FM services at good quality, although if you are a cable subscriber, you will need to refer to their literature to find out which services are on which frequencies. Obviously this only works for a receiver physically plugged into the cable, and for technical reasons this will not generally mix with the over the air services.
The Medium Wave band
For radio broadcast services this extends in frequency from 531 kHz to 1602 kHz. UK domestic services on this band comprise local, regional and national broadcasts, both Independent and BBC. Some radios are still calibrated in wavelengths rather than frequency. To convert frequency to wavelength, divide 300,000 by the frequency in kHz: e.g. 300,000 ÷ 1215 (kHz) = 247 metres.
For better Medium Wave reception
Other than in cars, Medium Wave is mostly received by an aerial internal to the radio (or personal stereo), or for hi-fi tuners, a wire loop on a frame. Stand the radio or loop aerial in the best orientation not only to maximise the strength of the station you want, but also, especially in darkness hours, to reduce interference from other stations on the same or nearby frequencies, or electrical interference from items such as fluorescent tubes or televisions. Each station may need a different orientation of the radio receiver or its aerial. Even on the same frequency, the best orientation can vary with time.
Buying new equipment
It is important to try out reception on all wavebands. Check for ease of tuning and quality of both reception and sound. Medium Wave (AM) reception inside a shop may be severely affected by televisions on nearby display, and the steel frame of the building structure.
With many more stations coming on-air, the ability of radios to reject interference from other transmissions on nearby frequencies is becoming more important. Basically, the gaps between the dial are filling up. Try and tune the set into as many different channels as possible, without interference, and compare different sets.
Some of the latest developments in radio sets are definitely worth having. Push-button tuning is commonly available; it is a good idea to make sure you have enough pre-sets to cope with the expanding range of services now becoming available. In the car, 'RDS' provides a convenient way of tuning to, and identifying, a chosen station. RDS signals are transmitted by most FM stations in the UK and further useful features are being introduced on newer RDS receivers.
But it sounds awful!
Most people who believe they suffer from poor reception either live outside the service area of the station they are trying to receive, or else have poor quality equipment (which may or may not be budget-priced). However, it is also the case that the AM and FM transmissions have inherent limitations. Even in-area, hills, buildings and trees can affect FM reception severely, by blocking signals, and also by reflecting them so that they interfere with a signal that has arrived by a direct path. AM signals cannot really get into steel-framed buildings. Also, AM is subject to interference from distant radio stations after dark; this can reach annoying levels towards the edge of the (daylight hours) service area of a given transmitter.
Unlicensed 'pirate' radio causes a significant amount of interference as well; the listener may be aware of a degradation to the wanted service, but would not be able to identify the cause, except in extreme cases.
Another common problem is from localised sources of electrical interference, such as some types of lighting, domestic appliances, and central heating thermostats; either yours or a neighbour's. This can affect both FM and, especially, AM. The Radio Investigation Service of the DTI's Radiocommunications Agency offers a service of investigation into interference complaints, though only relating to FM reception, and only within the service area of the transmitter whose transmissions are disrupted.
Another tip, for car reception, is to keep the receiving aerial clean. Electric aerials in particular are prone to collecting oily dirt which stops the signals passing on to the radio.
The RIS's address and telephone number are the same as those given for the Radiocommunications Agency on page (click here for more information). A fee is charged for investigations.
There is no central engineering information bureau for non-BBC services. Enquiries about particular radio services should be addressed to the station concerned. The Radio Authority itself has no staff who are dedicated to such enquiries. The Authority has available on request a composite list of transmitter locations and associated parameters.
The Authority actively supports the introduction of Digital
Radio, a new high-quality transmission system which will combat much more
robustly the problems faced by AM and FM. The first temporary services
began in 1996. Permanent digital radio services are now being advertised,
for more information) and will start to appear on the air from late 1999
onwards. FM and AM services would continue alongside digital radio for
quite a number of years, before consolidating these bands to support only
those stations not on digital by then.
Further information on tuning to the three national services can be found on the following links:
Revised: January 02, 2002 .