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Wireless microphones may operate on various frequencies, either licensed or unlicensed, depending on the country.
| | This article needs additional citations for verification .(April 2024) |
Wireless microphones may operate on various frequencies, either licensed or unlicensed, depending on the country.
In the UK, the use of wireless microphone systems requires a Wireless Telegraphy Act license, except for the license-free bands of 173.8–175.0 MHz and 863–865 MHz. These license-free bands are sometimes referred to as "Channel 70" (not to be confused with TV Channel 69, which operated on 854–862 MHz and always required a license from JFMG Ltd). [1] However, licenses are no longer available for TV Channel 69.
Arqiva acquired the PMSE band manager JFMG from ITV in February 2009. [2] JFMG was contracted by the communications regulator Ofcom to provide spectrum management and licensing services for Programme Making and Special Events (PMSE). However, in May 2015, Ofcom decided to terminate the contract with Arqiva and bring the existing services in-house. [3]
Channel 69 was replaced by Channel 38 (606 MHz to 614 MHz) as the UK mobile radio microphone band. Licenses to use this band are issued on a shared basis, meaning that any frequency coordination between multiple users in or around a specific location must be managed by the users themselves. All shared license holders have equal rights to use the band.
In 2013, the UK communications regulator Ofcom held an auction to sell the UHF band from 790 MHz to 862 MHz for mobile broadband services. [4] [5] This decision faced objections from Andrew Lloyd Webber and many others. [6] [7]
The interleaved UHF spectrum, also known as white space, between 470 MHz and 606 MHz (Channels 21–37) and 614 MHz and 694 MHz (Channels 39–48) can be licensed on a site-specific coordinated basis. Coordinated licenses grant the holder exclusive use of specific frequencies or spectrum blocks at a particular location for a defined period. Coordination between users is managed by Arqiva PMSE as part of the licensing process.
Frequencies are categorized as either regulated (requiring a license [8] ) or deregulated (license-exempt [9] ).
| Band | Frequency | Licencing | Description |
|---|---|---|---|
| VHF | 173.7 to 175.1 MHz | Deregulated | Typically, 3 to 4 frequencies can be accommodated. Ofcom examples: 173.800 MHz, 174.200 MHz, 175.000 MHz [9] 4-channel example: 173.800 MHz, 174.100 MHz, 174.500 MHz, 175.000 MHz (Note: Frequency 174.800 MHz may cause interference.) [10] |
| 175.25 to 209.8 MHz | Regulated | ||
| UHF | 606.5 to 613.5 MHz | Regulated | Formally known as "Channel 38," this band can typically accommodate 10 to 12 frequencies. [8] Sennheiser example frequencies (using Bank 1): 606.500 MHz, 606.875 MHz, 607.375 MHz, 608.000 MHz, 608.425 MHz, 609.325 MHz, 609.775 MHz, 610.425 MHz, 611.000 MHz, 611.400 MHz, 612.000 MHz, 613.275 MHz. [11] |
| 823 to 832 MHz | Regulated | Formally known as "Channel 65," also referred to as the "Duplex Gap," this band was introduced in March 2015. [8] Sennheiser suggest up to 12 microphone frequencies can be used in this band using G3 or newer equipment. | |
| 863.1 to 864.9 MHz | Deregulated | Formally known as "Channel 70," this band typically accommodates 4 frequencies. Examples include: 863.100 MHz, 863.700 MHz, 864.100 MHz, 864.900 MHz (Ofcom) [9] or 863.100 MHz, 863.500 MHz, 864.300 MHz, 864.900 MHz (Sennheiser, 2014). [13] Some equipment, such as the Sennheiser EW100 G3, may accommodate 6 frequencies, for example: 863.100 MHz, 863.400 MHz, 863.750 MHz, 864.225 MHz, 864.550 MHz, 864.975 MHz. [14] | |
| 1785 to 1805 MHz | Regulated | The 1.8 GHz band was added in March 2015. [8] | |
| 1880 to 1900 MHz | Deregulated | The 'DECT' band is used by Sennheiser's 'SpeechLine' range, with a typical latency of 19 ms. | |
| 2400 to 2483.5 MHz | Deregulated | The 'WiFi' band is also used for other purposes, including RFID, Bluetooth, microwave ovens, and industrial monitoring. [9] |
Licenses are required to use wireless microphones on vacant TV channels in the United States, as they are part of the Broadcast Auxiliary Service (BAS). However, this requirement is often overlooked and rarely enforced by the FCC. Licenses are available only to broadcasters, cable networks, and television and film producers. The FCC has issued a Report and Order [15] stating that it no longer allows Broadcast Auxiliary Service devices to operate in the 698–806 MHz portion of the spectrum due to the auction of the 700 MHz band. [16] This change is unrelated to, but often confused with, the White Space device debate currently taking place in the U.S.
The same Report and Order, issued on January 15, 2010, also permits most wireless microphones and other 'low power auxiliary stations' in the "core TV band" (TV channels 2 through 51, except 37) to operate with a transmit power of up to 50 mW without a license, under a special waiver of Part 15 rules. A rule change to make this permanent has been proposed.
Some wireless microphone manufacturers are currently marketing wireless microphones for use in the United States that operate within the 944 to 952 MHz band, which is reserved for studio-transmitter link communications. These microphones have the potential to interfere with studio-transmitter links, and their use must be coordinated by the Society of Broadcast Engineers. Licenses for this band are only available to licensees of radio and TV stations, and broadcasters are likely to report unauthorized use due to the high potential for interference.
Changes beginning in 2017 concern operations on 600 MHz frequencies. Starting in 2017, the amount of TV band spectrum available for wireless microphone use decreased as a result of the incentive auction, which was completed on April 13, 2017. A significant portion of the TV band spectrum in the 600 MHz band, including most (but not all) of the spectrum on TV channels 38 to 51 (614 to 698 MHz), was repurposed for the new 600 MHz service band for wireless services and will no longer be available for wireless microphone use. Specifically, wireless microphones operating in the new 600 MHz service band (617 to 652 MHz and 663 to 698 MHz frequencies) must cease operation by July 13, 2020, and may be required to stop earlier if they could cause interference to new wireless licensees that begin operations in the 600 MHz service band. Spectrum will still be available for wireless microphone use on TV channels 2 to 36 (frequencies below 608 MHz), portions of the 600 MHz guard band (614 to 616 MHz), the 600 MHz duplex gap (653 to 663 MHz), and other spectrum bands outside of the TV bands.[ clarification needed ]
In Australia, the operation of wireless microphones with up to 100 mW EIRP between 520 MHz and 694 MHz is permitted on unused television channels under a class license. This allows any user to operate the devices without obtaining an individual license. However, the responsibility falls on the user of the wireless microphone to resolve any interference caused to licensed radio communications services. After December 31, 2014, operation will no longer be allowed in the frequency range of 694–820 MHz. Please refer to item 22A in the schedule of the class license for more details. [17]
In many other countries, the use of wireless microphones requires a license. Some governments consider all radio frequencies to be military assets, and the use of unlicensed radio transmitters, including wireless microphones, may be severely punished.[ citation needed ]
Licensing in European countries is regulated by the Electronic Communications Committee (ECC), which is part of the European Conference of Postal and Telecommunications Administrations (CEPT) based in Denmark. [18]
The ISM radio bands are portions of the radio spectrum reserved internationally for industrial, scientific, and medical (ISM) purposes, excluding applications in telecommunications. Examples of applications for the use of radio frequency (RF) energy in these bands include RF heating, microwave ovens, and medical diathermy machines. The powerful emissions of these devices can create electromagnetic interference and disrupt radio communication using the same frequency, so these devices are limited to certain bands of frequencies. In general, communications equipment operating in ISM bands must tolerate any interference generated by ISM applications, and users have no regulatory protection from ISM device operation in these bands.
LPD433 is a UHF band in which license free communication devices are allowed to operate in some regions. The frequencies correspond with the ITU region 1 ISM band of 433.050 MHz to 434.790 MHz. The frequencies used are within the 70-centimeter band, which is currently otherwise reserved for government and amateur radio operations in the United States and most nations worldwide.
Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter. Radio waves with frequencies above the UHF band fall into the super-high frequency (SHF) or microwave frequency range. Lower frequency signals fall into the VHF or lower bands. UHF radio waves propagate mainly by line of sight; they are blocked by hills and large buildings although the transmission through building walls is strong enough for indoor reception. They are used for television broadcasting, cell phones, satellite communication including GPS, personal radio services including Wi-Fi and Bluetooth, walkie-talkies, cordless phones, satellite phones, and numerous other applications.
Code of Federal Regulations, Title 47, Part 15 is an oft-quoted part of Federal Communications Commission (FCC) rules and regulations regarding unlicensed transmissions. It is a part of Title 47 of the Code of Federal Regulations (CFR), and regulates everything from spurious emissions to unlicensed low-power broadcasting. Nearly every electronics device sold inside the United States radiates unintentional emissions, and must be reviewed to comply with Part 15 before it can be advertised or sold in the US market.
In the United States, the business band is the colloquial name used by radio users who utilize and scanner hobbyists who listen to the Federal Communications Commission (FCC) Industrial/Business pool frequencies. The regulations listing frequencies in this pool are contained in Subpart C of Part 90, Title 47 of the CFR.
A broadcast license is a type of spectrum license granting the licensee permission to use a portion of the radio frequency spectrum in a given geographical area for broadcasting purposes. The licenses generally include restrictions, which vary from band to band.
A spectrum auction is a process whereby a government uses an auction system to sell the rights to transmit signals over specific bands of the electromagnetic spectrum and to assign scarce spectrum resources. Depending on the specific auction format used, a spectrum auction can last from a single day to several months from the opening bid to the final winning bid. With a well-designed auction, resources are allocated efficiently to the parties that value them the most, the government securing revenue in the process. Spectrum auctions are a step toward market-based spectrum management and privatization of public airwaves, and are a way for governments to allocate scarce resources.
Spectrum management is the process of regulating the use of radio frequencies to promote efficient use and gain a net social benefit. The term radio spectrum typically refers to the full frequency range from 1 Hz to 3000 GHz that may be used for wireless communication. Increasing demand for services such as mobile telephones and many others has required changes in the philosophy of spectrum management. Demand for wireless broadband has soared due to technological innovation, such as 3G and 4G mobile services, and the rapid expansion of wireless internet services.
A wireless microphone, or cordless microphone, is a microphone without a physical cable connecting it directly to the sound recording or amplifying equipment with which it is associated. Also known as a radio microphone, it has a small, battery-powered radio transmitter in the microphone body, which transmits the audio signal from the microphone by radio waves to a nearby receiver unit, which recovers the audio. The other audio equipment is connected to the receiver unit by cable. In one type the transmitter is contained within the handheld microphone body. In another type the transmitter is contained within a separate unit called a "bodypack", usually clipped to the user's belt or concealed under their clothes. The bodypack is connected by wire to a "lavalier microphone" or "lav", a headset or earset microphone, or another wired microphone. Most bodypack designs also support a wired instrument connection. Wireless microphones are widely used in the entertainment industry, television broadcasting, and public speaking to allow public speakers, interviewers, performers, and entertainers to move about freely while using a microphone without requiring a cable attached to the microphone.
Cellular frequencies in the United States are allocated by the US Federal Communications Commission. As cellular mobile telephone technology has evolved over time, periodically bands of frequencies are reassigned from other radio services. Companies wishing to provide cellular services in a geographic region compete for the right to license radio spectrum in spectrum auctions. Different cellular companies in the same region may use different levels of cellular technology and different parts of the radio spectrum. In addition to radio frequencies used to connect handsets with cellular base stations, other parts of the radio spectrum are used to interconnect base stations and the wired telephone network. Some frequency bands may be vulnerable to interference by existing services in adjacent frequency bands, such as UHF television broadcasting.
In telecommunications, white spaces refer to radio frequencies allocated to a broadcasting service but not used locally. National and international bodies assign frequencies for specific uses and, in most cases, license the rights to broadcast over these frequencies. This frequency allocation process creates a bandplan which for technical reasons assigns white space between used radio bands or channels to avoid interference. In this case, while the frequencies are unused, they have been specifically assigned for a purpose, such as a guard band. Most commonly however, these white spaces exist naturally between used channels, since assigning nearby transmissions to immediately adjacent channels will cause destructive interference to both.
The United States 700 MHz FCC wireless spectrum auction, officially known as Auction 73, was started by the Federal Communications Commission (FCC) on January 24, 2008 for the rights to operate the 700 MHz radio frequency band in the United States. The details of process were the subject of debate among several telecommunications companies, including Verizon Wireless, AT&T Mobility, as well as the Internet company Google. Much of the debate swirled around the open access requirements set down by the Second Report and Order released by the FCC determining the process and rules for the auction. All bidding was required by law to commence by January 28.
Band V is the name of a radio frequency range within the ultra high frequency part of the electromagnetic spectrum. It is not to be confused with the V band in the extremely high frequency part of the spectrum.
Wireless Medical Telemetry Service (WMTS) is a wireless service specifically defined in the United States by the Federal Communications Commission (FCC) for transmission of data related to a patient's health (biotelemetry). It was created in 2000 because of interference issues due to establishment of digital television. The bands defined are 608-614 MHz, 1395-1400 MHz and 1427-1432 MHz. Devices using these bands are typically proprietary. Further, the use of these bands has not been internationally agreed to, so many times devices cannot be marketed or used freely in countries other than the United States.
The digital dividend refers to the radio spectrum which is released in the process of digital television transition. When television broadcasters switch from analog TV to digital-only platforms, part of the electromagnetic spectrum that has been used for broadcasting will be freed-up because digital television needs less spectrum than analog television, due to lossy compression. One reason is that new digital video compression technology can transmit numerous digital subchannels using the same amount of spectrum used to transmit one analog TV channel. However, the primary reason is that digital transmissions require much less of a guard band on either side, since they are not nearly as prone to RF interference from adjacent channels. Because of this, there is no longer any need to leave empty channels to protect stations from each other, in turn allowing stations to be repacked into fewer channels, leaving more contiguous spectrum to be allocated for other wireless services.
A short-range device (SRD), described by ECC Recommendation 70-03, is a radio-frequency transmitter device used in telecommunication that has little capability of causing harmful interference to other radio equipment.
The 800 MHz frequency band is a portion of the electromagnetic spectrum, or frequency band, that encompasses 790–862 MHz.
The Pan-American television frequencies are different for terrestrial and cable television systems. Terrestrial television channels are divided into two bands: the VHF band which comprises channels 2 through 13 and occupies frequencies between 54 and 216 MHz, and the UHF band, which comprises channels 14 through 36 and occupies frequencies between 470 and 608 MHz. These bands are different enough in frequency that they often require separate antennas to receive, and separate tuning controls on the television set. The VHF band is further divided into two frequency ranges: VHF low band between 54 and 88 MHz, containing channels 2 through 6, and VHF high band between 174 and 216 MHz, containing channels 7 through 13. The wide spacing between these frequency bands is responsible for the complicated design of rooftop TV antennas. The UHF band has higher noise and greater attenuation, so higher gain antennas are often required for UHF.
IEEE 802.11af, also referred to as White-Fi and Super Wi-Fi, is a wireless computer networking standard in the 802.11 family, that allows wireless local area network (WLAN) operation in TV white space spectrum in the VHF and UHF bands between 54 and 790 MHz. The standard was approved in February 2014. Cognitive radio technology is used to transmit on unused portions of TV channel band allocations, with the standard taking measures to limit interference for primary users, such as analog TV, digital TV, and wireless microphones.
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