What is DAB Radio?
July 19, 2007
What is Dab?
DAB stands for Digital Audio Broadcasting and is the move of the UK from analogue radio (FM and AM) to broadcasting on digital frequency. It is transmitted using 0’s and ones, as opposed to analogue which is transmitted in waves. It is a terrestrial based system, meaning it is transmitted just like analogue from towers and has location restrictions. It is not satellite radio.
DAB radio broadcasts on a section of bands in the frequency spectrum called band III. The advantage to this is that more channels can be had for the same radio space. It supposedly has clearer sound and will not suffer interference from cloudy weather or other radio stations.
Like analogue radio, and unlike much digital radio, receiving DAB broadcasts are free. The receiving equipment, i.e. radio to listen, must be purchased. Once the UK is sufficiently covered digitally, all analogue radio services will be phased out. Analogue radios cannot pick up DAB transmissions. A DAB receiver must be obtained to listen to DAB radio.
Radio Types
Digital radio can be heard on the same media as analogue radio such as: boom boxes, kitchen radios, car radios, alarm clocks, shower radios, and home stereos. It can also be heard on some media that are not generally used to listen to analogue radio such as: digital wristwatches, mp3 players, digital radio adaptors, digital broadcast television, and mobile phones. Digital radio broadcasts can only be heard on digital radios certified for Digital Audio Broadcasting. Look for the DAB seal to make sure the radio can pick up DAB broadcasts.
Radio Options
For the most part DAB receivers will be similar to its analogue (FM) radio counterpart. Here are some additional features:
• Digital Text Display - Dab radios have a small LCD display that will tell you the radio station you are on, the name and author of the song/broadcast, and any other information the station chooses to scroll. This display is the only way to see what channel you are choosing. Some units have text scan, which enables the listener to pause or scroll backwards and forwards through the text of a particular channel.
• EPG (electric programme guide) - EPG is accessible on the text display for the purpose of seeing multiple station schedules in advance of programmes. Only some units come with this feature.
• One Touch Tuning - DABs are not tuned with dials or by frequency. One touch tuning means you simply push the button or turn the knob (depending on the unit) and scroll through the stations by name until you find the station you would like to listen to.
• Rewind - Many DAB devices have the capacity to rewind, stop, or pause a live broadcast, retaining 5-45 seconds of memory depending on the unit. More expensive units can hold up to 10 minutes.
• Recording Channels - Some units have the option of recording DAB broadcasts onto tape, cd, ipod, or to a flash memory chip that can be taken to a digital playback device such as a computer or ipod.
• Presets/Timers -Presets for your favourite channels are available in the range of 2-200. You can also get various timers including kitchen and alarm clock. Some units can automatically switch channels for the alarm clock or timer.
• Lines In and Out - Depending on the unit you can get optical and line output for connection to a hi-fi system or built in AUX input for ipods or other music players (cd players etc.). AUX (auxiliary) inputs can be used to play mp3s. Units can also come with USB/mini USB ports (mostly for firmware updates) and in car chargers.
DAB radios can also come with traditional technology such as: headphone jacks, light up LCD displays, alarms (kitchen timers/wake up alarms), speaker connections, chargeable batteries or mains powered, splash or water resistance, remote controls and FM/AM capabilities.
Dual Band
The UK and parts of Europe broadcast DAB on Band III. However many parts of Europe (including Germany) and the world broadcast on L Band. Only a dual band radio will be able to pick up broadcasts on both Band III and L Band. This is necessary if you plan to use your DAB radio or device during travel abroad.
Adaptors
Adaptors are devices to convert your existing digital radio, mp3 player or other receiving unit to pick up DAB transmissions. They can also be used to receive DAB through your freeview (terrestrial) television service or satellite (SkyTV) television.
Aerials/Tuning
DAB signals should come with good coverage. Areas with weak coverage or inside shielded locations will require an aerial for good reception.
• Indoor aerials: Telescopic aerials, ribbon dipoles, and indoor flat aerials are choices for creating reception indoors. Handhelds and portable units usually have a telescoping aerial, which simply folds up from the unit as a thin adjustable pole. Indoor flat aerials look like a small place mat or mouse pad. They are more easily hidden but offer the weakest signal boost. Reception can also be built into headphones requiring no external equipment.
• Outdoor Aerials: There are two types of external aerials: dipole (omni-directional) and Yaggi (unidirectional) or element aerials. They must be affixed as high on the roof top as possible. Yaggi aerials must be aimed towards the DAB transmitter.
• In Car: Cars require a whip aerial, which would be in addition to the AM/FM aerial.
Terminology
• Frequency range - Like FM whose frequency range is 88.1- 108, DAB Band III is 174-240 MHz.
• Multiplex - A multiplex is the frequency equivalent of a mall. It is a group of stations in a band that a radio group can broadcast on. Each group or company may broadcast four or five different stations in their multiplex. Usually these stations are different genres.
• Secondary Services - These services are similar to part time radio stations that have only air programming at specific times or for specific events. To auto-set these stations you must tune into them, while they are actively airing. Then they can be saved to presets or set to automatically tune or flash when they broadcast.
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