Radio microphones

It is more than thirty years since radio microphones first appeared. Today they are in very widespread use in the audiovisual sector, as well as for conferences, public debates, concerts, etc… A radio microphone gives the speaker great freedom of movement. Generally low-power, they use different frequency bands. The use of such equipment is subject to the regulations on telecommunications.

Radio microphones saw the light of day with the appearance of transistors, which made it possible to miniaturise these devices. At that time, the technology enabled transmitters to be produced easily in the frequency ranges from 30 MHz to 200 MHz and the first radio microphones used those frequencies, sharing the frequency bands with other users.

Frequencies

Today, despite the efforts at harmonisation in Europe, the frequency bands allocated to the use of radio microphones are very often subject to national restrictions. European Radiocommunications Committee recommendation ERC/REC 70-03 concerning the use of short-range radio (SRD short-range devices) mentions the national restrictions for the 6 frequency bands available to radio microphones, together with the technical parameters, such as radiated power and the harmonised standards applicable in this area.

For Switzerland, the Federal Office of Communications (OFCOM) has adopted this document with its specific restrictions linked to the national frequency plan (NAFZ) and has issued a whole series of technical regulations.

The table below indicates the authorised power and the technical regulations for each frequency band (wireless microphones can be operated without a license):

Frequency band Maximum transit power Technical regulations Remarks

31.4 - 39.6 MHz

100 mW ERP

RIR1009-01

Use only in the channels indicated in RIR 1009-01

174 - 223 MHz

50 mW ERP

RIR1009-02

 

470 - 694 MHz 50 mW ERP RIR1009-10  
694 - 733 MHz 50 mW ERP RIR1009-10 Use only possible until 31.12.2018
738 - 786 MHz 50 mW ERP RIR1009-10 Use only possible until 31.12.2018
477 - 694 MHz 250 mW ERP RIR1009-11 Use only in the channels indicated in RIR 1009-11
701 - 726 MHz 250 mW ERP RIR1009-11 Use only in the channels indicated in RIR 1009-11 until 31.12.2018 possible
741 - 782 MHz 250 mW ERP RIR1009-11 Use only in the channels indicated in RIR 1009-11 until 31.12.2018 possible
823 - 826 MHz 20 mW EIRP
(ca. 12 mW ERP)
RIR1009-18 100 mW EIRP (ca. 60 mW ERP) for wireless microphones carried on the body

826 - 832 MHz

100 mW EIRP
(ca. 60 mW ERP)

RIR1009-13

 

863 - 865 MHz

10 mW ERP

RIR1009-05

 

1785 - 1800 MHz 20 mW EIRP
(ca. 12 mW ERP)
RIR1009-09 50 mW EIRP (ca. 30 mW ERP) for wireless microphones carried on the body or with built-in Spectrum Scanning Procedure (SSP)
1800 - 1804.8 MHz 20 mW EIRP
(ca. 12 mW ERP)
 RIR1009-09 50 mW EIRP (ca. 30 mW ERP) for wireless microphones carried on the body or with built-in Spectrum Scanning Procedure (SSP)

Notes:

  • The use of radio microphones in the bands 733 - 738 MHz, 786 - 789 MHz, 789 - 823 MHz and 832 - 862 MHz is forbidden.
  • As of 01.01.2019 the use of radio microphones in the bands 694 - 823 MHz is forbidden.
  • As of 01.01.2019 in the former TV band only the bands 470 - 694 MHz, 823 - 826 MHz and 826 - 832 MHz will be available.
  • Wireless microphones can also operate in some other frequency bands. For example, in the frequency ranges intended for non-specific short-distance radio applications or in the frequency range for DECT (Digital Enhanced Cordless Telecommunications) at 1880 MHz. The technical interface requirements RIR1008 define the frequency ranges and radio parameters for non-specific applications, the RIR0503-01 for DECT in the 1880 MHz frequency range.

Frequency coordination for licence exempted PMSE users

The coordination of frequencies used by wireless microphones at special events (e.g. concerts, exhibitions, press conferences, etc.) will no longer be handled by OFCOM. The Office will also cease to intervene in the event of interference caused by the simultaneous use of two or more wireless microphones on the same frequency. It should be noted that completely interference-free operation is not guaranteed for the frequencies available to wireless microphones. It is therefore the responsibility of the event organiser to commission specialist private companies or to let the various users on site reach agreement.

Licence exempted PMSE users can register equipment on a voluntary basis to the database provided by a third party in order to coordinate frequency use at events.

Placing on the market

Radio microphones are subject to compliance with the usual conditions for placing telecommunication equipment on the market: conformity assessment procedure successfully passed, declaration of conformity, marking and user information.

When radio microphones totaly or partly equiped with the frequency bands 733 - 738 MHz, 786 - 789 MHz, 789 - 823 MHz and 832 - 862 MHz (bands which cannot be used for radio microphones anymore) are placed on the market, the packaging must bear the indication of a restriction in Switzerland and the information that the radio microphone cannot be used on these frequency bands has to appear in the instructions for use (more information). This will avoid disturbances of other services.

Specialist staff
Last modification 12.04.2019

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