FMeXtra is a deprecated in-band on-channel digital radio broadcasting technology created by Digital Radio Express. Unlike iBiquity's HD Radio system, it uses any FM radio station's existing equipment and transmitter plant to transmit digital audio data on subcarriers instead of sidebands. It also requires no royalties for its use, which can run thousands of dollars per year for HD Radio because of the 3% of revenue on HD-2, HD-3 channels.

The system is run from a single rack unit box called the X1 Encoder, which is actually based upon a personal computer server and digital audio hardware from Lynx Studio Technologies (LST). Control is entirely via software, via gigabit Ethernet, USB, serial port, and SVGA video monitor. All processing is handled internally by a Pentium 4 running Windows XP.

FMeXtra is fully compatible with HD Radio, which uses additional radio spectrum beyond the ±100 kHz signal. It is not compatible with all existing subcarriers. Thus, a radio station might have to remove its radio reading service for the blind, and replace it (and its dependent listeners' receivers) with a digital one. This would take up much less bandwidth, particularly since voice can be highly compressed. The signal is partitioned so that RBDS, stereo, or other existing subcarriers can be protected, at the expense of bandwidth. If used only for monophonic transmissions, no RDS protection exists for stations in Europe.

The codecs used are AAC and aacPlus v1 and v2 and sample rates of 8 kHz (telephone quality) to 96 kHz (surround sound quality). The other codecs used are AMR-WB+ that can create more multiple audio programs as well as limited multimedia can also be broadcast, as with HD Radio and DAB. The available broadcasting bandwidth for digital audio varies from 40 kbit/s while sharing the space with existing analog signals, or 156 kbit/s if all analog signals (except the base monophonic signal) are dropped. (For comparison, iBiquity's Hybrid Digital/analog system offers 100-150 kbit/s in shared mode, and 300 kbit/s in pure digital mode.)

The coverage is similar to FM Stereo, and therefore high ERP is required in larger urban areas, as with normal FM transmissions.

Digital Radio Express has since gone out of business, after a brief stretch where it rebranded itself as VuCast in an effort to emphasize the technology's datacasting capabilities.

Stations broadcasting in FMeXtra

United States

and others

Minnesota Reading Services for the Blind has 25 FMeXtra encoders and 7,500 special FMeXtra receivers without a visual display.


FMeXtra is not in use anymore in the BeNeLux. Short test where running on the following stations:[2][3]

  • 93.9 Megastad, Rotterdam, The Netherlands, carrying Megastad Classics
  • 96.5 Imagine FM, Brussels, Belgium, simulcast
  • 98.4 Radio 538, Goes, The Netherlands, carrying Radio 10 Gold & JuizeFM
  • 100.4 Q-music, Rotterdam & Oude Polder, The Netherlands, carrying Radio Bem Bem
  • 100.7 Q-music, Lopik, The Netherlands, carrying Radio Bem Bem
  • 101.2 Sky Radio, Hilversum, The Netherlands, carrying TMF Radio & Kink FM
  • 101.9 Radio 538, Alphen, The Netherlands, carrying Radio 10 Gold & JuizeFM
  • 102.1 Radio 538, Hilversum, The Netherlands, carrying Radio 10 Gold & JuizeFM
  • 102.4 Radio 538, Terneuzen, The Netherlands, carrying Radio 10 Gold & JuizeFM
  • 102.7 Radio 538, Rotterdam, The Netherlands, carrying Radio 10 Gold & JuizeFM
  • 105.3 Delta Radio, Twente, The Netherlands, carrying Delta Piraat
  • 106.1 Gold FM, Brussels, Belgium, simulcast + carrying Jet FM

Rest of Europe

  • 89.1/Antenna 1: Heilbronn, Germany (soon on air)
  • 103.4/Otto FM: Varese, Italy, carrying Chic FM
  • 100.5/BBC WS: Riga, Latvia, Carrying Radio NORD and TOPradio

See also


  1. ^
  2. ^
  3. ^

1worldspace, known for most of its existence simply as 'WorldSpace', is a defunct satellite radio network that in its heyday provided service to over 170,000 subscribers in eastern and southern Africa, the Middle East, and much of Asia with 96% coming from India. It was profitable in India, with 450,000 subscribers.Timbre Media along with Saregama India planned to relaunch the company.The satellites AfriStar and AsiaStar however are now being used by the Yazmi USA, LLC run by WorldSpace's former CEO Noah A. Samara. The company claims to have built the first satellite-to-tablet content delivery system. The system primarily aims at providing educational services to rural areas in developing countries. The first pilots of the technology are said to be taking place in India (with 30,000 licenses) and the sub-Saharan region in Africa, with the latest trials in two schools in South Africa, in Rietkol, in Mpumalanga Province, and at Heathfield, in Western Cape.

All-Channel Receiver Act

The All-Channel Receiver Act of 1962 (ACRA) (47 U.S.C. § 303(s)), commonly known as the All-Channels Act, was passed by the United States Congress in 1961, to allow the Federal Communications Commission to require that all television set manufacturers must include UHF tuners, so that new UHF-band TV stations (then channels 14 to 83) could be received by the public. This was a problem at the time since the Big Three television networks (ABC, CBS, NBC) were well-established on VHF, while many local-only stations on UHF were struggling for survival.

The All-Channel Receiver Act provides that the Federal Communications Commission shall "have authority to require that apparatus designed to receive television pictures broadcast simultaneously with sound be capable of adequately receiving all frequencies allocated by the Commission to television broadcasting." Under authority provided by the All Channel Receiver Act, the FCC adopted a number of technical standards to increase parity between the UHF and VHF television services, including a 14dB maximum UHF noise figure for television receivers.


Broadcasting is the distribution of audio or video content to a dispersed audience via any electronic mass communications medium, but typically one using the electromagnetic spectrum (radio waves), in a one-to-many model. Broadcasting began with AM radio, which came into popular use around 1920 with the spread of vacuum tube radio transmitters and receivers. Before this, all forms of electronic communication (early radio, telephone, and telegraph) were one-to-one, with the message intended for a single recipient. The term broadcasting evolved from its use as the agricultural method of sowing seeds in a field by casting them broadly about. It was later adopted for describing the widespread distribution of information by printed materials or by telegraph. Examples applying it to "one-to-many" radio transmissions of an individual station to multiple listeners appeared as early as 1898.Over the air broadcasting is usually associated with radio and television, though in recent years, both radio and television transmissions have begun to be distributed by cable (cable television). The receiving parties may include the general public or a relatively small subset; the point is that anyone with the appropriate receiving technology and equipment (e.g., a radio or television set) can receive the signal. The field of broadcasting includes both government-managed services such as public radio, community radio and public television, and private commercial radio and commercial television. The U.S. Code of Federal Regulations, title 47, part 97 defines "broadcasting" as "transmissions intended for reception by the general public, either direct or relayed". Private or two-way telecommunications transmissions do not qualify under this definition. For example, amateur ("ham") and citizens band (CB) radio operators are not allowed to broadcast. As defined, "transmitting" and "broadcasting" are not the same.

Transmission of radio and television programs from a radio or television station to home receivers by radio waves is referred to as "over the air" (OTA) or terrestrial broadcasting and in most countries requires a broadcasting license. Transmissions using a wire or cable, like cable television (which also retransmits OTA stations with their consent), are also considered broadcasts but do not necessarily require a license (though in some countries, a license is required). In the 2000s, transmissions of television and radio programs via streaming digital technology have increasingly been referred to as broadcasting as well.

Digital audio broadcasting

Digital audio broadcasting (DAB) is a digital radio standard for broadcasting digital audio radio services, used in many countries around the world, though not North America.

The DAB standard was initiated as a European research project in the 1980s. The Norwegian Broadcasting Corporation (NRK) launched the first DAB channel in the world on 1 June 1995 (NRK Klassisk), and the BBC and Swedish Radio (SR) launched their first DAB digital radio broadcasts in September 1995. DAB receivers have been available in many countries since the end of the 1990s.

DAB is generally more efficient in its use of spectrum than analogue FM radio, and thus can offer more radio services for the same given bandwidth. However the sound quality can be noticeably inferior if the bit-rate allocated to each audio program is not sufficient. DAB is more robust with regard to noise and multipath fading for mobile listening, although DAB reception quality degrades rapidly when the signal strength falls below a critical threshold, whereas FM reception quality degrades slowly with the decreasing signal, providing effective coverage over a larger area.

The original version of DAB used the MP2 audio codec. An upgraded version of the system was released in February 2007, called DAB+, which uses the HE-AAC v2 audio codec. DAB is not forward compatible with DAB+, which means that DAB-only receivers are not able to receive DAB+ broadcasts. However, broadcasters can mix DAB and DAB+ programs inside the same transmission and so make a progressive transition to DAB+. DAB+ is approximately twice as efficient as DAB, and more robust.

In spectrum management, the bands that are allocated for public DAB services, are abbreviated with T-DAB, where the "T" stands for terrestrial.

As of 2018, 41 countries are running DAB services. The majority of these services are using DAB+, with only Ireland, UK, New Zealand, Romania and Brunei still using a significant number of DAB services. See Countries using DAB/DMB. In many countries, it is expected that existing FM services will switch over to DAB+. Norway is the first country to implement a national FM radio analog switchoff, in 2017, however that only applied to national broadcasters, not local ones.

Digital multimedia broadcasting

Digital multimedia broadcasting (DMB) is a digital radio transmission technology developed in South Korea as part of the national IT project for sending multimedia such as TV, radio and datacasting to mobile devices such as mobile phones, laptops and GPS navigation systems. This technology, sometimes known as mobile TV, should not be confused with Digital Audio Broadcasting which was developed as a research project for the European Union. DMB was developed in South Korea as the next generation digital technology to replace FM radio, but the technological foundations were laid by Prof. Dr. Gert Siegle and Dr. Hamed Amor at Robert Bosch GmbH in Germany. The world's first official mobile TV service started in South Korea in May 2005, although trials were available much earlier. It can operate via satellite (S-DMB) or terrestrial (T-DMB) transmission. DMB has also some similarities with the main competing mobile TV standard, DVB-H.

Digital radio

Digital radio is the use of digital technology to transmit or receive across the radio spectrum. Digital transmission by radio waves includes digital broadcasting, and especially digital audio radio services.

HD Radio

HD Radio is a trademarked term for Xperi's in-band on-channel (IBOC) digital radio technology used by AM and FM radio stations to transmit audio and data by using a digital signal embedded "on-frequency" immediately above and below a station's standard analog signal, providing the means to listen to the same program in either HD (digital radio with less noise) or as a standard broadcast (analog radio with standard sound quality). The HD format also provides the means for a single radio station to simultaneously broadcast one or more different programs in addition to the program being transmitted on the radio station's analog channel. It was originally developed by iBiquity. In September 2015 iBiquity was acquired by DTS bringing the HD Radio technology under the same banner as DTS' eponymous theater surround sound systems.. It was later acquired by Xperi in 2016.

It was selected by the U.S. Federal Communications Commission (FCC) in 2002 as a digital audio broadcasting method for the United States, and is the only digital system approved by the FCC for digital AM/FM broadcasts in the United States. It is officially known as NRSC-5, with the latest version being NRSC-5-D. Other digital radio systems include FMeXtra, Digital Audio Broadcasting (DAB) (Eureka 147), Digital Radio Mondiale (DRM30 and DRM+ configurations), and Compatible AM-Digital (CAM-D).

While HD Radio does allow for an all-digital mode, this system currently is used by some AM and FM radio stations to simulcast both digital and analog audio within the same channel (a hybridized digital-analog signal) as well as to add new FM channels and text information. Although HD Radio broadcasting's content is currently free-to-air, listeners must purchase new receivers in order to receive the digital portion of the signal.

By May 2018, HD Radio technology was claimed to be used by more than 3500 individual services, mostly in the United States. This compares with more than 2200 services operating with the DAB system.

HD Radio increases the bandwidth required in the FM band to 400 kHz for the analog/digital hybrid version. This makes adoption outside the United States problematic. In the United States the FM broadcast band channels have a spacing of 200 kHz, as opposed to the 100 kHz that is normal elsewhere. The 200 kHz spacing means that in practice, stations having concurrent or adjacent coverage areas will not be spaced at less than 400 kHz in order to respect protection ratios which would not be met with 200 kHz spacing. This also leaves space for the digital sidebands. Outside the US, spacing can be 300 kHz, which causes problems with the digital sidebands.

The FCC has not indicated any intent to force off analog radio broadcasts as it has with analog television broadcasts, as it would not result in the recovery of any radio spectrum rights which could be sold. Thus, there is no deadline by which consumers must buy an HD Radio receiver. In addition, there are many more analog AM/FM radio receivers than there were analog televisions, and many of these are car stereos or portable units that cannot be upgraded.

In-band on-channel

In-band on-channel (IBOC) is a hybrid method of transmitting digital radio and analog radio broadcast signals simultaneously on the same frequency.

By utilizing additional digital subcarriers or sidebands, digital information is "multiplexed" on an AM or FM analog signal, thus avoiding re-allocation of the broadcast bands. However, by putting RF energy outside of the normally-defined channel, interference to adjacent channel stations is increased when using digital sidebands. The addition of the digital sidebands works better in the United States, where the FM broadcast band channels have a spacing of 200 kHz, as opposed to the 100 kHz that is normal elsewhere. The 200 kHz spacing means that in practice, stations having concurrent or adjacent coverage areas will not be spaced at less than 400 kHz. Outside of the US, spacing can be 300 kHz, which causes problems with the IBOC digital sidebands.

IBOC does allow for multiple program channels, though this can entail taking some existing subcarriers off the air to make additional bandwidth available in the modulation baseband. On FM, this could eventually mean removing stereo. On AM, IBOC is incompatible with analog stereo, and any additional channels are limited to highly compressed voice, such as traffic and weather. Eventually, stations can go from hybrid mode (both analog and digital) to all-digital, by eliminating the baseband monophonic audio.

Radio 10 (Netherlands)

Radio 10 (formerly : Radio 10 Gold and Radio 10 FM) is a Dutch commercial radio station that mostly focuses on songs from the 1970s to 2000s, with a moderate amount of mid 1960s' and 2010s' hits. It is one of the oldest, still remaining, commercial radio stations of the Netherlands.

Radio in the United States

Radio broadcasting in the United States has been used since the early 1920s to distribute news and entertainment to a national audience. It was the first electronic "mass medium" technology, and its introduction, along with the subsequent development of sound movies, ended the print monopoly of mass media. During radio's "Golden Age" it had a major cultural and financial impact on the country. However, the rise of television broadcasting in the 1950s relegated radio to a secondary status, as much of its programming and audience shifted to the new "sight joined with sound" service.

Originally the term "radio" only included transmissions freely received over-the-air, such as the AM and FM bands, now commonly called "terrestrial radio". However, the term has evolved to more broadly refer to streaming audio services in general, including subscription satellite, and cable and Internet radio.

Sky Radio

Sky Radio is a Dutch commercial radio station playing non-stop Adult Contemporary-pop music, owned by Talpa Holding. The station focuses on men and women between 25 and 54 years of age and is programmed according to the AC format (any popular song from the 1980s to today that is not rap/hip hop, hard rock, or dance). It is DJ-free and the music is only interrupted to broadcast news, weather, advertisements and traffic reports.

Sound multiplex in broadcasting

In broadcasting, sound multiplex is a method to deliver alternative audio feeds on television and radio channels.


A subcarrier is a sideband of a radio frequency carrier wave, which is modulated to send additional information. Examples include the provision of colour in a black and white television system or the provision of stereo in a monophonic radio broadcast. There is no physical difference between a carrier and a subcarrier; the "sub" implies that it has been derived from a carrier, which has been amplitude modulated by a steady signal and has a constant frequency relation to it.

Subsidiary communications authority

Subsidiary Communications Authorization (SCA) in the United States, and Subsidiary Communications Multiplex Operation (SCMO) in Canada, is a subcarrier on a radio station, allowing the station to broadcast additional services as part of its signal.

Subcarrier signals

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