Dab Factsheet

BBC DAB Digital Radio While most listeners enjoy trouble-free DAB reception, some may experience problems receiving our services.The advice within this factsheet is designed to help these listeners.

Unreliable reception and burbling sound A weak FM signal would give a hissing sound. DAB is different. If the signal strength is weak you can hear break-up (burbling noises) or even complete silence. With a portable radio, ensure the aerial is fully extended.Try placing it higher up, even try upstairs and keep away from metal surfaces such as a fridge. Sometimes the building itself can be a problem (thick stone or reinforced walls); a window-sill position may help. Unfortunately, some radios are less sensitive than others and need careful positioning to work reliably. If your radio displays signal strength, use this as a guide to ensure the best position. For the best reception an external aerial gives best results.This is especially true with hi-fi units.

Lost reception

Lost reception is usually due to a reduction in the signal strength from just above to just below the threshold of reception. It’s very rare for the problem to be caused by transmitter faults. Radios can lose sensitivity if they develop a fault or if batteries run low. Consider what may have changed in your home or nearby which could have affected the strength of signals.

DAB aerials

DAB uses different frequencies from TV and FM so a different type of aerial is needed. First, check if the radio can take an external aerial (please refer to the user manual or contact the manufacturer). A DAB aerial may be known as BAND 3.There are two main types of DAB aerials, Omni-directional and directional. In most cases you should use the omni type, which looks like a vertical rod and will see the BBC DAB signal from various transmitters.This is a good thing as the signal can be stronger and more services may be received. In some circumstances a directional aerial may be better. A good installer would know what is best at your location. The Confederation of Aerial Industries (CAI) is a trade body representing installers who guarantee their work and operate to a Code of Practice.Their website (www.cai.org.uk) has details of local installers, and member installers usually place the CAI logo on advertisements in local directories. 1

Postcode coverage predictions When your postcode is entered online at www.bbc.co.uk/digitalradio the predicted results for DAB coverage are displayed. ‘Very Likely’ and ‘May Receive’ stations are listed. If the results are ‘Very Likely’, you should be fine but ‘May Receive’ is not as certain; your radio may work fine, may have problems or receive nothing. Some radios need much more signal than others to work reliably. Because of this, the Postcode Predictions should only be used as a guide. If the guide suggests you should have good reception and you are in an average location but your radio does not work well, you could try taking the radio back to the shop to exchange it for a different model.You may find an improvement.

Differences between BBC and .commercial stations Different transmitter sites are used between the various broadcasters, so it’s possible to receive services from one transmitter site and not another.This may be reflected in a DAB postcode predictor, where predictions vary between ‘may receive’ and ‘very likely’. An omni-directional outside aerial may help.

BBC Local Radio Local stations (and nations’ stations in Scotland,Wales and Northern Ireland) use capacity made available by commercial platform operators under rules set by OFCOM, the telecoms and broadcasting regulator. In some areas, a commercial licence has not yet been awarded so BBC local radio is not yet available on DAB. OFCOM are aware of the difficulty this causes and are pursuing ways to make more capacity available for local commercial DAB. DAB Digital Radio coverage of a BBC Local Radio station may not match that which is available on analogue FM or AM medium wave because a different transmitter network may be used. Please note that the only local radio stations you may receive on DAB will be ones for your area.

Interference on DAB DAB reception can suffer if the level of interference is high. This can sound like forms of ‘pops’ followed by short silences. If disruption is regular, domestic equipment may be the cause. To confirm this, try listening to FM when the problem is present. A distinct crackle indicates a burst of interference. Central heating thermostats and any general electrical 2

appliances (including lights) could be the cause.Turn these off briefly to see if reception improves. If you can’t track it down, contact OFCOM on 0845 456 3000, or visit their website at www.ofcom.org.uk and request their leaflet and form about radio and TV interference.

Part-time ‘secondary’ services BBC Radio Five Live Sports Extra and ‘Radio 4 Long Wave’ are ‘secondaries’ alongside the main ‘primary’ station.When they are transmitting, many radio sets have a ‘secondary’ light which comes on when you tune to the primary station.You then need to press the ‘secondary’ button to tune in. Alternatively you may see an arrow next to the service name (i.e. BBCR4> or BBC5Live>).This is also an indication that a secondary service is available. A simple turn of the tuning dial to the next service should access the stations. Test Match cricket is normally broadcast on BBC Radio Five Live Sports Extra on DAB. Radio 4 LW is generally used only for Yesterday In Parliament and the Daily Service (Act of Worship).

Finding new services Digital radios may need prompting to find new stations. Press ‘autotune’, ‘scan’, or ‘autoscan’ occasionally to update your set.

Time delay on Digital Radio This is simply due to both transmitting and receiving processing that is needed to make DAB work. If you are concerned about accuracy to the second of ‘pips’ for setting your clock you should still use the analogue broadcast.

Loudness of BBC stations BBC Radio 3 and Radio 4 can often sound quiet compared to commercial stations.This allows the listener to appreciate a more realistic audio level (dynamic range), especially when listening to classical music.This is not to everyone’s taste, especially if you are listening in a noisy environment. Switching on Dynamic Range Control (DRC) on the radio set (check your manual) will make the station’s audio sound more level, like commercial stations.

Car reception problems Car aerials (especially the rear windscreen type) optimised for FM/AM often do not give good results for DAB. If you are having DAB reception problems in your car, we recommend you seek advice from your car radio dealer.

Future coverage expansion The BBC is committed to improving DAB coverage to eventually reach 90% of the UK population, as detailed in the BBC’s Building Public Value document.The BBC Digital Website (bbc.co.uk/digitalradio) gives details of new transmitter openings, with the Postcode Checker on the same site being updated shortly afterwards.

DAB Technical Details UK DAB band (Band III): 217.5 – 230 MHz Utilisation: 7 ‘ensembles’ each 1.536 MHz wide designated 11B-11D &12A-12D BBC National Ensemble Multiplex transmits on Block 12B: Centre Frequency 225.648 MHz

3