UK Titles Editorial
The labels on a radio describe several different parts of listening. Some identify a broadcast system, some describe the way stations are grouped, and others explain the information shown on the screen. Knowing which is which makes a receiver’s mode menu and reception guidance much easier to follow.
These seven terms were chosen because they appear on radio controls, in specifications or in UK listening guides. They cover the route by which sound reaches the set and the extra data that can accompany it. The definitions also help explain why finding a station name, receiving its broadcast and playing an online stream involve different things.
1. DAB: digital audio broadcasting
DAB stands for Digital Audio Broadcasting, as WorldDAB’s technical glossary sets out. It is a system for broadcasting radio digitally over the air. A receiver decodes the transmitted information to produce the sound.
Digital Radio UK’s listening guide describes familiar features such as tuning at the touch of a button and displaying station and track information. That helps explain the experience of selecting from a list of named services rather than relying only on a position on a frequency dial.
DAB identifies the broadcast technology. It does not, by itself, specify every feature a set has: a separate Bluetooth or internet mode has its own purpose. The term also needs to be read alongside DAB+, because the two labels have a practical compatibility distinction.
2. DAB+: a different way to code the audio
DAB+ builds on the DAB broadcast system with a newer audio-coding method. WorldDAB identifies the codec as HE-AAC v2. A codec is the method used to encode and decode the audio information.
Digital Radio UK explains that DAB+ uses the same transmitters and broadcast technology as DAB, while coding the sound differently and using capacity more efficiently. DAB and DAB+ services can be carried alongside each other.
The important listener distinction is receiver support. Many older DAB sets receive DAB services only; a DAB+ service needs a DAB+-enabled receiver. Some specific DAB-only models can be upgraded, but that depends on the model and its manufacturer. A fresh station scan does not establish that a radio can decode DAB+. The plus sign concerns the audio format, rather than a promise that every older set can acquire it.
3. Multiplex or ensemble: the bundle carrying stations
A multiplex is a group of services carried together. Ofcom describes a DAB multiplex as a bundle of different radio stations, digitised and compressed before transmission to receivers. Its guidance distinguishes local, regional, national and small-scale multiplexes.
Ensemble is another term for this grouping. WorldDAB’s glossary explains that its programme and data services share a fixed overall capacity. The individual station and the multiplex carrying it therefore have separate identities.
For example, a receiver’s information display may name the programme service on one line and its ensemble on another. Those labels describe the station and the bundle through which it arrives. This is useful when reading technical details: the multiplex name is not necessarily the name you select to hear a particular programme.
4. FM: frequency modulation
FM describes a way of putting information onto a radio-frequency carrier. Analog Devices’ technical explanation shows that the carrier’s frequency varies with the information being sent. For familiar FM radio broadcasting, that information represents the audio programme.
Ofcom’s analogue broadcast engineering code identifies the VHF band from 87.5 to 108 MHz for FM broadcasting. MHz means megahertz, the unit used for the frequency numbers on the dial.
A displayed frequency is a tuning detail: it identifies the carrier the receiver is using. It does a different job from a station name or a DAB+ compatibility label. A set can also display additional information while playing an FM broadcast, through the RDS system described below.
5. AM, MW and LW: method and wavebands
AM means amplitude modulation. Here the information changes the amplitude, or size, of the carrier signal, as Analog Devices explains. The technical distinction from FM concerns the part of the signal that changes.
The BBC’s radio engineering paper on the AM bands explains the connection with the labels found on older receivers. MW means medium wave and LW means long wave: these describe different wavebands commonly associated with AM broadcasting. AM describes the modulation method; MW and LW describe the part of the spectrum involved.
That is why an AM-labelled control and separate MW or LW controls can appear on different sets. The wording tells you about the tuning system and band. A waveband marking on a radio is not a current list of stations broadcasting there.
6. Internet radio: audio delivered online
Internet radio receives a stream through an internet connection. Digital Radio UK’s internet-radio explanation describes sets connecting through Wi-Fi and accessing online stations, with on-demand programmes and podcasts also available on internet-enabled radios.
The connection matters. The Australian Broadcasting Corporation’s technical help guide confirms that listening to DAB+ uses no internet connection or data, whereas listening to internet streams uses data. Both involve digital audio, but the delivery paths are different.
On a set with several modes, choosing internet radio selects its online listening route. Choosing a DAB or FM mode selects a broadcast receiver instead. A station’s appearance in an online directory therefore does not establish that its over-the-air signal is available at the radio’s location.
7. RDS: information alongside FM
RDS stands for Radio Data System. The RDS Forum explains that it adds a digital data channel to FM, helping receivers identify programmes, retune and display service information. The audio can still be an FM broadcast even when the screen shows a station name.
Its feature glossary distinguishes Programme Service name, the identifying label, from RadioText, which carries text messages. It also explains Alternative Frequencies, information that can help a suitable receiver move between transmitters carrying the same programme.
These are supporting features rather than separate listening sources. A name or scrolling message tells you about information accompanying the programme; the FM, DAB or internet mode tells you about the route carrying its audio. Reading both together makes the radio’s display far less mysterious.
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