New arrangements for wireless microphones

As a result of the need to clear the digital dividend spectrum, wireless microphone users will need to clear the spectrum by 1 January 2015.

The Australian Communications and Media Authority announced, on 13 May, changes to frequency ranges used for wireless microphones. The changes are a key plank in supporting the transition of wireless microphones from the digital dividend band.

“This transition is intended to deliver satisfactory spectrum outcomes for the countless thousands of activities that the industry facilitates,” said ACMA Chairman, Chris Chapman. “It has become a necessary consequence of the introduction of new 4G broadband mobile services across Australia into the digital dividend.”

The changes made are arrangements for wireless audio transmitters in the Radiocommunications (Low Interference Potential Devices) Class Licence 2000.

The changes to the class licence:

• mean that after 31 December 2014, wireless audio transmitters (including wireless microphones) will no longer be authorised to operate in the frequency range 694-820 MHz (the digital dividend band);
• introduce new arrangements supporting the use of digital wireless audio transmitters in the frequency range 520-694 MHz;
• introduce new arrangements supporting the use of wireless audio transmitters operating in the frequency range 1790-1800 MHz.

As a corollary, ACMA will be working to update its standards’ arrangements to restrict the supply of wireless microphones that operate in the digital dividend (694-820 MHz).

“The dialogue with the Australian Wireless Audio Group (AWAG) and its industry forum has been collaborative and iterative. I want to encourage industry to continue to engage as we transition to these new arrangements,” Chapman said.

A copy of the Radiocommunications (Low Interference Potential Devices) Class Licence 2000 is available on the ComLaw website. The ACMA website also provides a range of useful material for potentially affected users.

Clearing the airwaves

The introduction of digital television and switch-off of analog television into Australia has made possible a reduction in the amount of radiofrequency spectrum needed to support broadcast television services - the ‘digital dividend’. However, wireless audio systems (including wireless microphones) also operate within the television broadcasting spectrum in unused channels. These systems are low power and are allowed to operate under the Radiocommunications (Low Interference Potential Devices) Class Licence 2000, on the condition that no interference is caused to other radio communications services and no protection is provided from interference.

Digital television services are to be ‘restacked’ by the end of 2014 to clear spectrum to support new high-speed broadband mobile (4G) services across Australia. The digital dividend auction commenced in April 2013 and results were announced on 7 May 2013.

Clearance of the digital dividend spectrum is required by 1 January 2015 and this includes clearance by wireless microphone users. Restacking of digital television services will occur area by area prior to that date. The need for changes to the class licence and the restacking of digital television services flow from the announcement of the digital dividend by the Minister for Broadband Communications and the Digital Economy in June 2010.

These changes are the culmination of a number of earlier initiatives concerning information provision and consultations. For example, the ACMA has been in ongoing consultation with representatives of the wireless audio system suppliers (AWAG) on the impacts of these changes since the declaration of the digital dividend by the Minister in 2010. In 2011, the ACMA first published specific information about the impact of the digital dividend on wireless microphones.

ACMA held a Spectrum Workshop on wireless microphones on 7 December 2012, providing information on spectrum options available for wireless microphones and updating participants on future planning. That information was steadily updated as planning for the digital dividend progressed and now includes an ‘Indicative Channel Chart’ for the restack of digital television services which provides information by area on what channels will be used post restack and hence what channels will be unused (ie, the white space).

These initiatives, combined with both the DBCDE website (which includes a March 2013 restack timetable) and the mySwitch website (which provides television coverage area maps) provide information to determine availability of spectrum for wireless microphone use on an area-by-area basis.

The changes

In December 2012, ACMA released the invitation for comment IFC 49/2012 on the proposed changes to the class licence. The consultation period closed on 13 March 2013 after receiving 52 submissions. The authority agreed to make the variation on 18 April 2013 with minor amendments. There are three changes in this round of updates to the LIPD class licence that affect wireless microphone users.

The first is a change to the currently permitted operating frequency range for wireless audio transmitters from 520-820 MHz to 520-694 MHz after 31 December 2014 to exclude the digital dividend band (694-820 MHz). The second change was the introduction of arrangements to support the use of wireless audio transmitters using digital modulation in the frequency range 520-694 MHz. The third change was the introduction of arrangements to support the use of wireless microphones in the frequency range 1790-1800 MHz.

ACMA is working through Standards Australia to reflect the changes in the licence in the Australian standard (that is picked up by the ACMA mandatory standard for short-range devices). ACMA will also be proposing changes to the requirements for the supply of wireless audio devices brought into Australia. It is also using Google AdWords to provide information on eBay and online about the changes.

ACMA is continuing to work with industry through the AWAG to assist affected users to plan ahead for the replacement or retuning of wireless microphone equipment. Information on the current and future availability of frequencies for wireless microphone use in the frequency range 520-694 MHz on an area-by-area basis through information on the television channel restack process can be found on the mySwitch website or through the restack of digital television services indicative restack channel chart available on the ACMA website.