General FAQs | ACMA

General FAQs

Download the fact sheets for 'plug and play' users, professional users and suppliers. The fact sheets provide everything you need to know about the changes and what you can do to prepare.

Please note that the information below was published prior to the fact sheets being made available.  

Important changes: 

From 1 January 2015, wireless microphones and other wireless audio devices (such as, in-ear monitoring systems, public announcement systems and instrument pick-ups) will no longer be able to operate in the 694-820 MHz frequency range. The restack of television services will also change the spectrum availability below 694 MHz.


Check with your manufacturer or supplier to find out if your wireless microphone and other wireless audio device will be affected.



Subscribe to the ACMA's free monthly e-bulletin to get updates on the changes affecting wireless microphones.


Currently, a large number of wireless audio systems and devices operate within the frequency range 520-820 MHz. This frequency range is the same as that used by television broadcasting. The wireless audio systems are low power, and are allowed to operate under a Low Interference Potential Device (LIPD) class licence in the unused television channels on the basis of no interference, and no protection from interference.

Television services are currently in the process of changing over from analog to digital. This switch-over will change the ranges of frequencies that television services use, and will therefore affect the spectrum available for wireless audio equipment.

This web page provides users of wireless audio equipment with information on the analog-to-digital television changeover process and how it might affect the use of their equipment.


What is happening?

Television in the UHF bands is currently broadcast on frequencies between 520 MHz and 820 MHz. On 24 June 2010, the Minister for Broadband, Communications and the Digital Economy announced that by switching from analog to digital television, 126 MHz of this spectrum would be cleared in Australia. This means that after the changeover from analog to digital television, only the range 520-694 MHz will still be used for UHF television broadcasting, while the 694-820 MHz range will be made available for other services.

wireless_mics_image_1 jpg

What is the digital dividend?

The block of spectrum which will be cleared through the switchover to digital television is often referred to as the "digital dividend".

The digital dividend spectrum is able to be cleared because digital television broadcasting makes more efficient use of the spectrum than the corresponding analog services. Currently both analog and digital television services are being broadcast, with the analog services being progressively switched off on a region-by-region basis across Australia. More information on the switch-off of analog telelvision is available.

The diagram above shows the use of the affected part of the spectrum before and after the digital switch-over.

When are the changes happening?

There are two phases to the digital television switchover that need to be completed before the digital dividend spectrum will be clear and available for other uses. The first phase is the switch-off of analog television services. This is being done on an area-by-area basis, with the final regions to be switched off by 31 December 2013.

After the switch-off is complete in each area, there will still be digital television services operating in the digital dividend frequency range. The second phase is known as the "restacking", where the digital services will be moved so they all operate below 694 MHz. This process will also take place over a period of time on an area-by-area basis with the current target date for completion being the end of 2014.

It should be noted that due to the area-by-area switchover, it is possible that some of the areas that are 'restacked' earlier may be made available before the process is completed everywhere else.

The diagram below gives an example, illustrating how the use of the spectrum will change step-by-step through the switch-over process. The diagram is to illustrate the general concept only, and is not supposed to accurately represent any actual existing, or future, channel arrangement or rearrangement.

1. Analog television operating only
2. Digital television begins. Both analog and digital television in operation at once.
3. Analog television finishes. Only digital remains operating.
4. Digital services are all relocated to channels below 694 MHz. Digital dividend is now cleared, and ready for use by other services.

wireless_mics_image_2 jpg

What frequencies will be available for audio equipment after the switchover?

The main frequency ranges that can be used to operate wireless audio transmitters from 1 January 2015 are 520–694 MHz and 1790–1800 MHz. A full list of other available frequency ranges is on the ACMA’s website.

  • 520-694 MHz (Remaining broadcasting spectrum)

The frequencies from 520-694 MHz will continue to be used for terrestrial broadcasting and the unused TV channels or 'white spaces' in this range will still be available for use by wireless audio equipment, in the same way as they are at the moment.

The government’s intention is that restack will be completed by 31 December 2014. The restack channel chart and timetable set out where and when digital television services will be restacked across Australia. This information should enable wireless audio transmitter users to determine what spectrum below 694 MHz will be available in a given area. 


Some suppliers of wireless audio transmitters also have other resources to help you find out what spectrum is available, given your area and chosen transmitter.

  • 694-820 MHz (Digital Dividend spectrum)

The frequency range 694-820 MHz will be continued to be available for wireless audio equipment until 31 December 2014. 

Much of the 126 MHz of the digital dividend spectrum will be used for next generation mobile broadband services such as LTE and 4G from 1 January 2015.

The digital dividend was replanned to provide for 2 x 45 MHz blocks of spectrum to support next new mobile broadband services. These will be separated by a 10 MHz mid-band gap and guard bands at either end.

Future use of the mid-band gap and guards is dependent on the outcomes of replanning of the 803-960 MHz frequency band.  The ACMA is currently considering proposals to replan the 803–960 MHz frequency band to improve its utility and potentially make additional spectrum available in the medium term for mobile broadband services. This would include providing a public safety mobile broadband capability in the 803–820 MHz part of that band.

Once the outcomes of this review are known, the ACMA will investigate the feasibility of using portions of the digital dividend guard band (694–703 MHz) and mid-band gap (748–758 MHz) for wireless audio transmitter use.  With the need to accommodate services displaced by the replanning outcomes, it is likely that only a portion of the 694‑703 MHz guard band will be available for wireless audio transmitters. 

The diagram below illustrates the spectrum arrangements in the band.

wireless_mics_image_3 jpg

The LIPD class licence indicates that the band 694 MHz to 820 MHz will not be available for use after 1 January 2015. However, once the results of the reviews are known the LIPD class licence will be further updated to reflect spectrum or bands that will be available for use by wireless audio equipment.

Will my audio equipment still work?

This depends mainly on what range of frequencies your equipment is able to operate over. Equipment which operates below 694 MHz should be able to operate just as it does at the moment, unless it happens to fall within a range that the digital channels get 'restacked' to. 

When will we know more specific details of the spectrum available for wireless audio equipment?

The ACMA began technical discussions with interested and affected stakeholders regarding the use of the digital dividend in 2011. The channel arrangements for digital television services in the remaining broadcasting spectrum became available at the end of 2012. Outcomes of the review of the 800/900 MHz band should be available towards the end of 2013.

The ACMA will also continue to engage with the wireless microphone industry, on an ongoing basis, throughout the planning process, particularly through industry representative groups, such as the Australian Wireless Audio Group (AWAG).

What if I want/need to buy new equipment now?

The ACMA recommends the purchase of equipment that operates in the remaining broadcast spectrum 520-694 MHz with the widest possible tuning range.

The larger the range of frequencies over which a piece of equipment can operate, the more likely it will be able to find an available portion of spectrum among the parts in use.

To help protect consumers from buying equipment that can no longer be used after 31 December 2014, the ACMA has also revised regulations to require suppliers to:



  • stop importing and manufacturing wireless audio equipment that operates in the 694-820 MHz range by 31 December 2013, and
  • include a warning label on equipment that informs the buyer that they must not use it in this frequency range after 31 December 2014. The revised rules do not apply to compliant wireless microphones and audio devices already in the market.

How do I find out what spectrum/frequencies are available in my area?

Detailed restack channel planning work commenced in 2011 and is now complete. In the early stages of channel planning, to provide a framework that allowed the detailed channel planning for each licence area to proceed relatively independently, a ‘key sites indicative channel plan’ was developed. It has now been superseded by a more comprehensive digital television channel chart for the restack of digital television services. The digital television channel chart (previously known as the Indicative Channel Chart) provides a visual representation of the current channels and planned or post restack channels Australia wide. 

The channel chart is available for download from the ACMA's restack webpage.

The Minister announced on the 19 June 2012, that Broadcast Australia had been appointed to develop an indicative nationwide restack timetable, in consultation with industry and ACMA. The latest restack channel change timetable is available from the Department of Communications' website.

The channel chart and the restack timetable should provide enough information for users to determine the availability of spectrum for use in an area.

Who should I contact for more information?

Subscribe to our free monthly e-bulletin, visit the wireless microphones hub on our website or send us your questions to

Your equipment supplier and/or manufacturer should also be able to assist you with details of specific equipment you may own or need.

Last updated: 12 April 2019