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Wireless microphones may operate over various frequencies, licensed or unlicensed depending upon the country.
In the UK, 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, sometimes referred to as "Channel 70" (not to be confused with TV Channel 69, which was 854–862 MHz and always required a license from JFMG Ltd [1] although licences are no longer available for that band).
Arqiva purchased PMSE band manager JFMG from ITV in February 2009. [2] JFMG were contracted by communications regulator OFCOM to provide spectrum management and licensing services for programme making and special events (PMSE). In May 2015 Ofcom made the decision to end the contract with Arqiva and to insource the existing services. [3]
Channel 69 was replaced as the UK mobile radio microphone band by channel 38 (606 MHz to 614 MHz). Licences to use this band are issued on a Shared basis which means that any frequency coordination between multiple users in or around a particular location must be done by those users themselves. All Shared Licence holders have the same rights as each other.
In 2013 the UK communications regulator, Ofcom, held an auction in which the UHF band from 790 MHz to 862 MHz was sold to be used for mobile broadband services. [4] [5] Objections had been raised by Andrew Lloyd Webber and many others. [6] [7]
The Interleaved (also known as White Space) UHF spectrum between 470 MHz to 606 MHz (Channels 21 - 37) and 614 MHz to 694 MHz (Channels 39 to 48) may be licensed on a Site Specific Coordinated basis. Coordinated licences grant the holder exclusive use of particular frequencies or blocks of spectrum at a particular location for a specified period of time. Coordination between users is carried out by Arqiva PMSE as part of the licensing process.
Frequencies are licensed either as regulated (licence required [8] ) or deregulated (licence exempt [9] ).
| Band | Frequency | Licencing | Description |
|---|---|---|---|
| VHF | 173.7 to 175.1 MHz | Deregulated | Typically can accommodate 3 to 4 frequencies. OfCom examples: 173.800, 174.200, 175.000 [9] 4 channel example: 173.800, 174.100, 174.500, 175.000 (frequency 174.800 can cause interference) [10] |
| 175.25 to 209.8 MHz | Regulated | ||
| UHF | 606.5 to 613.5 MHz | Regulated | Formally 'Channel 38'. Typically can accommodate 10 to 12 frequencies. [8] Sennheiser example frequencies using bank 1: 606.500, 606.875, 607.375, 608.000, 608.425, 609.325, 609.775, 610.425, 611.000, 611.400, 612.000, 613.275. [11] |
| 823 to 832 MHz | Regulated | Formally 'Channel 65', aka 'Duplex Gap', added 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 'Channel 70'. Typically can accommodate 4 frequencies, for example: 863.100, 863.700, 864.100, 864.900 (ofcom) [9] or 863.100, 863.500, 864.300, 864.900 (Sennheiser, 2014). [13] Some equipment, such as Sennheiser EW100 G3, may accommodate 6 frequencies, for example: 863.100, 863.400, 863.750, 864.225, 864.550, 864.975. [14] | |
| 1785 to 1805 MHz | Regulated | 1.8Ghz band, added in March 2015. [8] | |
| 1880 to 1900 MHz | Deregulated | 'DECT' band. Utilised by Sennheiser's 'Speechline' range, with typical latency of 19ms. | |
| 2400 to 2483.5 MHz | Deregulated | 'WiFi' band. Other uses may include 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 a 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, television and film producers. However, the FCC has issued a Report and Order [15] stating that they now no longer allow Broadcast Auxiliary Service (BAS) devices to operate in the 698–806 MHz portion of the spectrum due to their auction of the 700 MHz band. [16] This change is unrelated to, but commonly confused with, the White Space device debate that is currently taking place in the U.S.
The same Report and Order, issued 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 transmit power up to 50 mW without a license, under a special waiver of Part 15 rules. A rule change to make this permanent is proposed.
There are currently some wireless microphone manufacturers that are marketing wireless microphones for use in the United States that operate within the 944 to 952 MHz band 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 in this band are only available to licensees of radio and TV stations, and broadcasters are likely to report unauthorized use in this band due to the high potential for interference.
Changes beginning in 2017 concerning operation on 600 MHz frequencies. Beginning in 2017, the amount of TV band spectrum available for wireless microphone use is decreasing 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), has been repurposed for the new 600 MHz service band for use by wireless services, and will not continue to be available for wireless microphone use. Specifically, wireless microphones that operate in the new 600 MHz service band (the 617 to 652 MHz and 663 to 698 MHz frequencies) will be required to cease operation no later than July 13, 2020, and may be required to cease operation sooner if they could cause interference to new wireless licensees that commence operations on their licensed spectrum in the 600 MHz service band. Spectrum will continue to be available for wireless microphone use on the other TV channels 2 to 36 (TV band frequencies that fall below 608 MHz), on portions of the 600 MHz guard band (the 614 to 616 MHz frequencies) and the 600 MHz duplex gap (the 653 to 663 MHz frequencies), and in various other spectrum bands outside of the TV bands.[ clarification needed ]
In Australia, operation of wireless microphones of up to 100 mW EIRP between 520 MHz and 694 MHz is on unused television channels and is covered by a class license, allowing any user to operate the devices without obtaining an individual license. The onus, however, is on the user of the wireless microphone to resolve any interference that the use of the microphone may cause to licensed radio communications services. After 31 December 2014 operation will not be allowed in the frequency range 694-820 MHz. See item 22A in the schedule in the class licence [17]
In many other countries wireless microphone use requires a license. Some governments regard all radio frequencies as military assets and the use of unlicensed radio transmitters, even 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.
Citizens band radio is a land mobile radio system, a system allowing short-distance one-to-many bidirectional voice communication among individuals, using two-way radios operating near 27 MHz in the high frequency or shortwave band. Citizens band is distinct from other personal radio service allocations such as FRS, GMRS, MURS, UHF CB and the Amateur Radio Service. In many countries, CB operation does not require a license and may be used for business or personal communications.
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.
Citizens band radio is a system of short-distance radio communications between individuals on a selection of 40 channels within the 27-MHz band. In the United Kingdom, CB radio was first legally introduced in 1981, but had been used illegally for some years prior to that.
Multichannel multipoint distribution service (MMDS), formerly known as broadband radio service (BRS) and also known as wireless cable, is a wireless telecommunications technology, used for general-purpose broadband networking or, more commonly, as an alternative method of cable television programming reception.
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.
Digital terrestrial television in the United Kingdom encompasses over 100 television, radio and interactive services broadcast via the United Kingdom's terrestrial television network and receivable with a standard television set. The majority of digital terrestrial television (DTT) services, including the five former analogue channels, are broadcast free-to-air, and a further selection of encrypted pay TV services are also available.
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.
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.
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.
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.
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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