Narrowband area service licensing | ACMA

Narrowband area service licensing


This information paper provides details of the licensing arrangements applicable to narrowband area service (NAS) stations.

A NAS station is a station that:

  1. is operated under a broadcasting licence
  2. provides one-way radio transmission to not less than 4 narrowband area receivers and
  3. uses an occupied bandwidth not exceeding 4 megahertz.

What is a NAS station?

The operation of a NAS station is authorised by a radiocommunications apparatus licence issued under the narrowband area service licensing option within the broadcasting licence type.

NAS stations are normally authorised to provide a service using non broadcasting services band frequencies. NAS stations may operate in appropriate parts of the VHF and MF frequency bands. Technical considerations for VHF and MF operation are detailed in Attachment 1 and Attachment 2 respectively.

The NAS licensing option is defined in the Radiocommunications (Interpretation) Determination 2000. - this one is old url

Broadcasting Services Act 1992 licensing considerations

Under the Broadcasting Services Act 1992 (the BSA), the ACMA is responsible for regulating the broadcasting industry, including licensing, programming and ownership and control of broadcasting services. The transmitter licence issued by the ACMA under the Radiocommunications Act 1992 (the Radcomm Act) for a NAS station concerns only the technical characteristics of the station.

NAS stations are usually used to provide 'narrowcasting' programming (within the meaning of the Broadcasting Services Act 1992). Narrowcasting services must have reception limited in some way (for example, by being targeted at special interest groups). Such operation is authorised under a class licence issued, by the ACMA, under the BSA.

However a NAS station licensee who wishes to provide 'broadcasting' programming (within the meaning of the BSA) must obtain a broadcasting services band licence under Part 4 (commercial broadcasting) or Part 6 (community broadcasting) of the BSA. This is in addition to the transmitter licence issued under the Radcomm Act. The use of NAS stations for this purpose is relatively uncommon.

If a NAS station licensee is unsure about whether a programming format is 'broadcasting' or 'narrowcasting', he or she may seek an opinion from the ACMA about into which category a service or proposed service fits. This mechanism is designed to enable service providers to be certain about which regulatory conditions apply to their broadcasting service under the Broadcasting Services Act 1992. The ACMA charges a fee for giving an opinion about category of service.

While it is not compulsory for potential NAS station operators to apply to the ACMA for an opinion about into which category a service or proposed service fits, it is an offence to operate a broadcasting service without a broadcasting services bands licence (in other words, a licence issued by the ACMA under the BSA). There are significant fines, that accumulate daily, for operating a broadcasting service without a broadcasting services bands licence.

Note that an opinion from the ACMA about into which category a service or proposed service fits, is not a licence and confers no rights, especially in relation to access to either the broadcasting services bands or to non broadcasting services bands spectrum.

For further advice about this issue, please contact the ACMA's Sydney Office on Freecall 1800 226 667.

Minister's direction restricting provision of commercial broadcasting services

On 6 November 2002 NAS station licensees were limited in how they could provide commercial broadcasting services. On that day, the Minister for Communications, Information Technology and the Arts provided the former ACA with the direction, Australian Communications Authority (MF NAS Transmitter Licences) Direction No. 1 of 2002. The Minister directed the former ACA to restrict all MF NAS transmitter licensees from operating a NAS station to provide a commercial broadcasting services unless:

  1. the licence was issued by the ACA before 6 November 2002;
  2. the commercial broadcasting service is permitted by a commercial licence allocated before 6 November 2002;
  3. the commercial broadcasting service commenced before 6 November 2003; and
  4. the location of the station is within 10 km of its location on 6 November 2002.

Then in June 2003 the Department of Communications, Information Technology and the Arts released the Discussion Paper: Proposed Direction Regarding Medium Frequency Narrowband Area Service Licences. As a consequence of the responses to the Discussion Paper, on 29 August 2003 the Minister provided the former ACA with the Australian Communications Authority (MF NAS Transmitter Licences) Direction No. 1 of 2003 which directed the former ACA to impose conditions that restrict MF NAS transmitter licences from operating a NAS station to provide a commercial broadcasting service unless:

  1. the licence was issued by the former ACA before 6 November 2002;
  2. the commercial broadcasting service is permitted by a commercial licence allocated before 6 November 2002;
  3. the commercial broadcasting service commenced before 29 August 2004; and
  4. the location of the station is within 10km of its location on 6 November 2002 or, if the location of the station is outside this 10km radius, the ACA has determined that:
    1. transmissions from the new location would provide a service to substantially the same intended audience as the audience that was intended to be covered from the location of station on 6 November 2002; and
    2. transmissions from the new location would not significantly interfere with any existing radiocommunications services.

The ACMA's procedures for site relocation of MF NAS transmitter licences can be found in Attachment 3.

The conditions provided in the Minister's 2003 direction have been reflected in the Radiocommunications Licence Conditions (Broadcasting Licence) Determination No. 1 of 1998.

Licence conditions

The operation of radiocommunications equipment authorised by a broadcasting transmitter licence authorising a NAS station is subject to:

  • conditions specified in the Radcomm Act, including an obligation to comply with the Radcomm Act;
  • a condition that any radiocommunication device operated under the licence comply with all standards applicable to it;
  • conditions specified in the Radiocommunications Licence Conditions (Apparatus Licence) Determination No. 1 of 1997 and any other determinations made by the ACMA under paragraph 107(1)(f) of the Radcomm Act;
  • conditions specified in the licence; and
  • any further conditions imposed by the ACMA under section 111 of the Radcomm Act.

Generally, conditions are applied to licences to enable users to communicate effectively with a minimum of interference. All conditions relating to a licence must be complied with.

Licence conditions determinations

The ACMA may determine, by written instrument, conditions relating to apparatus licences. These conditions are known as Licence Conditions Determinations (LCDs).

The Radiocommunications Licence Condition (Apparatus Licence) Determination 2003 contains licence conditions that are common to all apparatus licences.

The conditions applicable to NAS stations are contained in the Radiocommunications Licence Conditions (Broadcasting Licence) Determination No. 1 of 1998.

An advisory note is automatically attached to licences where a LCD is in force. The note references the applicable LCD.

The licence conditions imposed through the relevant LCD may change from time to time. Licensees should ensure that they have informed themselves of the current conditions imposed by the ACMA.

Special conditions

Any other conditions of operation which apply to an individual licence but are not included in the LCD, will be printed on the licence under the heading 'Special Conditions'.

An accredited person may ask the ACMA to impose one or more special conditions on the licence according to the circumstances in which the frequency assignments for the licence are made.

Advisory notes

Advisory notes, providing information that may be of interest to a licensee, will be printed on the licence under the heading 'Advisory Notes'.

An accredited person may ask the ACMA to impose one or more advisory notes on the licence according to the circumstances in which the frequency assignments for the licence are made.


The licensee of a NAS station must use either a form of identification that clearly identifies the station, or a callsign allocated by the ACMA, at the start of each transmission or series of transmissions.

Callsigns are a unique combination of letters and numbers allocated to a radiocommunications user to identify a station. Callsigns must be used for all on-air communications including testing. Callsigns allocated to NAS stations conform with International Telecommunication Union Radio Regulations (see Table 1 for callsign template).

Table 1 - NAS callsign template

aaamnn NAS callsign template (example of typical callsign VKA714)


first two alpha characters are VJ, VK, VL, VM, VN, VZ, or AX, with the third character being any alpha


numeric character 2 - 9


numeric character 0 - 9


Apparatus licences may be issued for periods varying from one day to up to five years. However, the most common period is one year.

Applying for an apparatus licence

Applications for an apparatus licence may be made to the Radiocommunications Licensing and Assignments Section, ACMA, Canberra. Applicants should complete the ACMA form Application for Apparatus Licence(s) (R057). If frequency assignments are required with this licence, the frequency coordination work may be performed either by the ACMA or an accredited person.

If the work is to be done by the ACMA a form Application for Additional Station Information (R077) should also be submitted with the licence application.

Alternatively if you wish to use the services of an accredited person you should refer to the List of Accredited Persons for contact details. An accredited person will issue you with a frequency assignment certificate and this should be submitted with the licence application to the ACMA. Accredited persons are not employed by the ACMA, nor is the ACMA responsible for the work of accredited persons.

More information about Accreditation can be found on the ACMA website.

Because of the high level of interest in operating in the MF band and the commercial competitiveness of applicants for licences, the ACMA has instituted a strict regime of allocating frequencies on a priority listing. The priority listing is derived from the date of receipt of a complete application. Among other things, applications should contain exact site details and be accompanied by the licence fee.

There are unlikely to be any MF NAS frequencies available in the Canberra, Sydney, Melbourne, Gold Coast/Brisbane and Perth areas. Frequency availability is also very restricted in surrounding regional areas. So that applicants may gauge the likelihood of an application being successful before applying, they are encouraged to apply, to the ACMA, for a Frequency Scan, which lists the location of all NAS services in a particular band.

The ACMA's administrative fee is not generally refundable, whether or not a licence is issued. This is because, if a licence application is refused due to the unavailability of a frequency or site, and ACMA has undertaken coordination work to determine that fact, the ACMA is required to recover its costs for the time taken to complete its investigations.


Spectrum is a valuable resource. Fees are intended to ensure a fair return to the Commonwealth for the private use of this valuable public resource. Licence fees are set having regard to spectrum location, geographical location, amount of spectrum occupied and coverage area authorised by the licence.

Detailed information about fees is provided in the Apparatus Licence Fee Schedule booklet.

Licence fees exemptions and concessions

Individuals and organisations may be eligible for an exemption or concession from the payment of licence fees. For further information see Licence Fee Exemptions and Concessions.

Transfers of apparatus licences

Apparatus licences may be transferred. Applicants wishing to transfer an apparatus licence should complete and submit to the ACMA, the form Application for Transfer of Apparatus Licence(s) (R060). The transfer form must be signed by both the transferer and the transferee. Applicants are required to pay a transfer charge to cover the ACMA's administrative expenses.

There are a number of limitations on the transfer of apparatus licences. The Radiocommunications (Transfer of Apparatus Licences) Determination 2000 specifies these limitations.

A device authorised by the transferred licence is still required to operate under the same technical conditions (including transmission site) as specified on the original licence.

In deciding whether to approve the transfer of a licence, the ACMA must consider the interference potential of the service authorised by that licence. An example of this would be where a licensee has indicated acceptance of interference caused between services operating from the same transmitter location. While it is possible that such operation could be managed if those services are operated by the same licensee, it may be more difficult if those licences are transferred to another operator.

Please note that any transfer of a NAS licence should not occur without the licensee making the transferee aware of any advice from the ACMA of the conditions which apply to the services. The ACMA will be able to deal with a transfer more quickly if the ACMA is provided with written confirmation by both the transferor and the transferee that they are aware of the potential for interference and nevertheless agree to the transfer.

For example, in the past, some licences were issued with frequency reuse and adjacent channel distances less than those generally specified. These were either licences issued to the one licensee, or licences where the licensees had reached an agreement on interference management. The ACMA is unlikely to approve the transfer of any of these licences without the relevant transmitters being relocated to accord with the specified frequency and distance separation criteria.

Licence variations

Licence variations attract a charge dependant on the nature of the work required. Variation of a transmitter site requires re-coordination with other services. The degree of work involved in such a variation may attract a charge approaching, or equal to, the administrative charge for a new service.

Third party authorisation

Licensees may authorise, by written instrument, other persons to operate radiocommunications devices under the apparatus licences. These are known as third party authorisations.

There are a number of limitations on third party authorisations. The Radiocommunications (Limitation of Authorisation of Third Party Users) Determination 2000 specifies these limitations.

A person authorised to use a radiocommunications device under a third party authorisation is subject to all of the conditions applicable to that device under the licence.

Further information

If you have any additional queries relating to this, or any licence type, please contact the Radiocommunications Licensing and Assignments Section.

Attachment 1

Technical Parameters and Frequency Assignment Criteria for VHF NAS

VHF NAS technical parameters

VHF NAS station transmitters, in a technical sense, operate under similar arrangements to land stations in the Land Mobile licence type. Detailed information about frequency assignment for land stations is provided in the Radiocommunications Assignment and Licensing Instruction Frequency Assignment Requirements for the Land Mobile Services (LM 08).

The technical parameters that apply to VHF NAS stations are:

  1. a maximum Equivalent Isotropically Radiated Power (EIRP) of 83 watts;
  2. an emission bandwidth of 16 kHz (in the past, more than 16 kHz was permitted but new services will only be allowed a maximum of 16 kHz); and
  3. Radiocommunications Standard (Analogue Speech (Angle Modulated) Equipment) No. 1 of 1995.

The band segments employed for VHF NAS are:

  • 70.00000 to 70.24375 MHz and 77.29375 to 77.49375 MHz (segments A and G of the VHF Mid Band Frequency Band Plan [70 to 87.5 MHz]) and
  • 151.39375 to 152.49375 MHz and 173.29375 to 174.00000 MHz (segments F and W of the VHF High Band Frequency Band Plan [148 to 174 MHz]).

Assignment of VHF NAS are restricted to the segment 151.39375 to 152.49375 MHz unless this segment is unavailable.

VHF NAS frequency assignment criteria

Frequency assignment criteria for NAS stations in the VHF bands are the same as those for standard single frequency land stations in the land mobile service with the exception that transmission may be continuous. Care will be taken by the ACMA regarding intermodulation products between VHF NAS stations and International Maritime Mobile (IMM) channels. While mobile receivers are not normally protected from interference, IMM services are primarily safety-orientated and will be protected, especially in areas where a NAS station site is in very close proximity to IMM equipment.

Attachment 2

Frequency Assignment Criteria for MF NAS

Service description

An MF NAS is intended to provide narrowcasting programming in the band 1606.5 to 1705 kHz. This band is popular with applicants as it lies just above the AM radio broadcasting band and is suitable for reception by some standard broadcasting receivers.

The 1606.5 kHz to 1705 kHz band is available for MF NAS under subclause 10(3) of the Australian Radiofrequency Spectrum Plan.

The channelling arrangements are for 9 kHz channel spacing with the first channel at 1611 kHz. The channel spacing is consistent with Australian broadcasting service channel arrangements and has been used considering the performance of standard broadcast receivers and to take advantage of the existence of 9 kHz whistle filters in some broadcast receivers. Frequencies that are available are:

1611, 1620, 1629, 1638, 1647, 1656, 1665, 1674, 1683, 1692, and 1701 kHz.

Service performance

The design of typical AM radio receivers requires the transmitted signal to be an amplitude modulated double side band, full carrier transmission and the assignment criteria are, therefore, designed with this in mind. For the purpose of maintaining consistency with other services in the band, the transmitter power for MF NAS has been limited to 400 watts and the necessary bandwidth limited to 6 kHz. As a result, the performance, grade of service and coverage distance may be less than that of broadcasting services operating in the broadcasting services bands.

Licensees of MF NAS stations are reminded that each licence is subject to an ACMA licence condition that specifies the bandwidth of the transmitter. This condition is specified on each licence and forms part of the emission designator 6K00A3E. This designator means the station operated under the licence must use double sideband full carrier amplitude modulation and must not exceed a necessary bandwidth of 6 kHz.

Recognising the need, in practice, to allow for audio filter roll off, the ACMA has adopted the principle that it will accept that licensees are compliant with the necessary bandwidth licence condition if the occupied bandwidth of the emission is contained within the 9 kHz channel width in which MF NAS services operate. Occupied bandwidth is the bandwidth containing 99% of the mean power of the emission.

As a guide, the ACMA considers that the applicable 6 kHz necessary bandwidth and 9 kHz channel spacing requirements will be met by the following audio modulation levels:

  • at 3 kHz, 3 decibels (dB) below the maximum
  • at 4.5 kHz, 23 dB below the maximum and
  • at greater than 4.5 kHz, at least 23 dB below the maximum.

The coverage distance is intended to be around 10 kilometres, but in practice may vary depending on the location of receivers, and the use of the same frequency and adjacent frequencies by other users. In the initial stages of the growth of services, it is likely that greater interference-free coverage distances will be possible, however the coverage distance will decrease as more services commence operation.

The greater the distance separation between receivers and the wanted transmitter, the greater the level of interference from other services. It is this level of interference which will limit the coverage distances. On the other hand, broadcasting services are planned so that interference from other broadcasting services does not occur. To minimise the level of interference between services using the same frequency, it is necessary that transmitters use vertical antenna polarisation. This may be achieved by the use of a vertical monopole radiator.

Discussions with licensees have revealed that some do not realise the effect of the limitations applicable to MF NAS and what they will mean to users of the service. It is also of concern that in some cases the investment which licensees are making in their services is greater than would normally be justifiable considering the level of performance that may be expected. It is recommended that applicants carefully consider the limitations and restrictions that apply to an MF NAS before committing to any investment.

As those receiving a NAS may become concerned about increased levels of interference resulting from the operation of additional transmitters, it is also recommended that listeners be advised, in advance, of the potential for interference.

Frequency availability

Frequency availability is dictated primarily by the co-channel and adjacent channel performance of typical receivers. Frequencies selected using the following criteria should result in a satisfactory level of service for receivers situated within 10 kilometres of the transmitter:

  • for co-channel, 160 kilometres (km) separation between transmitters;
  • for adjacent channels (ie separated by 9 kHz), 30 km separation between transmitters; and
  • for channels separated by 18 kHz and greater, no distance separation between transmitters is specified.

The ACMA has recently concluded that there is scope for varying the 160 km co-channel separation distance (and thus providing licensees with greater flexibility to move the location of MF NAS transmitters) as the separation distance is based on worst case propagation and noise conditions. However, prospective MFNAS licensees should note that quantifying what co-channel reuse value is appropriate in a specific location would require additional engineering studies by the licensee. A detailed report A Derivation of the Co-Channel Reuse Distance for Stations in the Medium Frequency Narrowband Area Service (MF NAS) outlining an examination of the range over which the actual co-channel separation distance can vary, is available from the ACMA website.

The ACMA no longer permits co-siting of transmitters.

The general level of electromagnetic noise may further limit the coverage area in urban locations to around 7 km. Lower levels of noise in non urban areas have the potential to permit greater coverage distances of 20 km in suburban and 48 km in rural areas. As a result, in rural areas it should be possible to achieve a satisfactory grade of service over distances greater than 10 km where co-channel and adjacent channel services permit.

Satisfactory grades of service may not be realised where AM radio broadcasting transmitters or other types of transmitters operate either co-channel, or within two adjacent channels (+/- 18 kHz) within propagation distance of service receivers. This also applies for other services in the band whose special conditions and operating characteristics differ from those employed here. In those cases, it may be necessary for applicants to reach agreement with existing users before operation will be authorised, and an appropriate special condition will be applied to the licence specifically to cover potential interference with those existing services.

The ACMA will not assign 1611 kHz in areas served by AM radio broadcasting stations operating on 1602 kHz.

Some narrowcasting service stations have been licensed to operate on MF NAS frequencies. These licences were issued prior to the NAS licence type being introduced. These low powered stations (typically 1 to 5 watts) mostly operate in schools and colleges on 1611 kHz. A narrowcasting service station operating on an MF NAS frequency will be treated as a NAS station for the purpose of frequency coordination.

MF NAS transmitters should be sited away from telecommunications facilities (for example, PABXs) as interference may result.

Transmitting antenna

The transmitting antenna employed must be designed to produce only vertically polarised radiation. This may be achieved by the use of a vertical monopole radiator. Other antenna types may be used providing that the resulting component of sky wave radiation is no greater than that for a vertical monopole radiator.

Transmitting antennas that maximise ground wave radiation and that minimise sky wave radiation will result in optimum reception of transmissions in a licensee's coverage area while minimising interfering signals to other users of the frequency at distant locations.

Potential interference to broadcasting services

NAS station licensees have certain obligations regarding not causing interference to the reception of broadcasting services. The location of a NAS station's transmitter is very important in relation to its potential for causing interference, and it should be separated from all locations of broadcasting receivers by at least 400 metres.

To reduce the potential for interference to the reception of broadcasting transmissions, NAS station licensees should consider following a start up procedure to determine the effects of the transmitter before commencing permanent operation. The types of potential interference commonly experienced should be known to technical consultants, otherwise such information may be obtained from the ACMA.

Proposed services should be brought to the attention of the community within one km of the transmitter for the purpose of inviting comment on any interference experienced.

While it is not compulsory, it would be in the best interests of MF NAS station operators to comply with parts 1 and 2 of the ACMA's Technical Planning Guidelines (TPGs) dated December 2003, relating to 'start up' and 'change of transmitter site'. Because of the potential for interference from MF NAS stations to AM radio broadcasting services, the testing requirements of parts 1 and 2 of the TPGs would provide a means for MF NAS station operators to trial the effects of their transmitters before committing themselves.

A particular concern is the possibility of interference to the reception of broadcast programs resulting from a proposed MF NAS operating close to an image frequency of a broadcast service. (Image frequency interference is a type of interference related to the demodulation process in AM receivers). Broadcast frequencies potentially affected may be determined from:

Broadcasting frequency = MF NAS frequency - 910 kHz

If the calculated frequency is within the 18 kHz channel width of an MF broadcast transmitter serving the area in which the MF NAS is proposed to operate, then higher than normal minimum distance separations between the MF NAS transmitter and MF broadcast receivers need to be maintained. ACMA will take this into account when considering whether to approve a proposed service.

The obligation to not cause interference to the reception of broadcasting services is an ongoing obligation, which applies to both existing and future broadcasting services. In this respect, ACMA will not consider the existence and operation of MF NAS in its planning. In circumstances where the operation of a proposed AM radio broadcasting transmitter may result in broadcast receiver image interference involving an existing MF NAS station, the MF NAS station operator would need to take necessary corrective measures.

Attachment 3

Procedures for site relocation of MF NAS transmitter licences

An MF NAS licensee authorised to operate within the frequency range of 1606.5 kHz to 1705 kHz who wishes to relocate a transmitter by 10 kms or more from the transmitter site at 6 November 2002 must:

  • arrange for a qualified broadcasting engineer to determine:
  1. the population within the estimated coverage area of the transmitter site specified at 6 November 2002;
  2. the population within the estimated coverage area of the proposed new transmitter site; and
  3. the overlap population, if any, between the estimated existing and proposed coverage areas, identified in the previous two steps, expressed as a percentage of the population of the estimated existing coverage area. If the resulting percentage is at least 30%, it will be assumed that substantially the same intended audience will be served from the proposed new transmitter site.


  1. The coverage area of a station is to be determined using an acceptable signal propagation model to estimate the relevant adequate signal contours, defined to be the 10mV/m contour in urban areas, 2.5mV/m in suburban areas and 0.5mV/m in rural areas (see the ACMA publication Technical Planning Parameters and Methods for Terrestrial Broadcasting).
  2. The estimated coverage area must be based on ACMA criteria for reference receiver performance and ground wave propagation, and must not include sky wave propagation (see the ACMA publication Technical Planning Parameters and Methods for Terrestrial Broadcasting).
  3. Provide a signed submission informing the ACMA of the results and certifying that proper methodology has been used, enclosing population estimates determined in steps 1-3 above and a map or maps showing estimated signal strength contours from the existing site and the proposed site.

Procedures for applications to change the location of MF NAS transmitters in cases not meeting the 160 km co-channel separation distance criteria

Licensees wishing to change the location of MF NAS transmitters must submit an assessment from a qualified broadcast engineer that demonstrates that an appropriate methodology has been used and certifying that the MF NAS protection requirements are maintained.

To ensure minimal deviation from the MF NAS model, requests for variations from the co-channel separation requirement of more than 10% (that is, not closer than 144 km) will not be considered.

Last updated: 17 December 2012