Radiocommunications Advisory Guidelines (Managing Interference to Spectrum Licensed Receivers – 3.4 GHz Band) 2025

The instrument introduces and relies on a set of precise technical and administrative concepts. The core defined terms are in section 5 and in Schedule 1. Key concepts and their mechanical effect are:

• 3.4 GHz band and 3.4 GHz receiver. The 3.4 GHz band is 3400 MHz to 3800 MHz (s 5). A 3.4 GHz receiver is a radiocommunications receiver operated under a 3.4 GHz spectrum licence (s 5). The definitions determine the scope of the instrument , the protections and requirements apply only to devices operating in that band and under spectrum licences.

• Device boundary criterion. The device boundary criterion is central for in-band interference management. For transmitters operated under 3.4 GHz spectrum licences the term has the meaning given by the section 145 Determination; for transmitters under transmitter licences it means the test set out in RALI MS 47 for permitted location of the device boundary (s 5, definition). This criterion is used as if a transmitter were an area-wide licence transmitter in a range of situations (s 8(2)).

• Emission buffer zones and core licence conditions. The instrument treats interference management as being accomplished by emission buffer zones created via core licence conditions under section 66 of the Act, a section 145 determination about unacceptable interference and registration conditions, and these advisory guidelines themselves (s 7(2)).

• Notional receiver performance level. The instrument sets a notional receiver performance level that the ACMA will use when setting compatibility requirements (s 12(2); Schedule 1). This is a default set of receiver performance thresholds , principally adjacent channel selectivity, intermodulation response rejection and receiver blocking , referenced to sensitivity levels (Schedule 1(1)-(3)).

• Compatibility requirement. Defined in Part 5 and Schedule 2, the compatibility requirement is the transmitter-side limit intended to protect a fixed receiver that meets the notional performance level and is registered. The numerical expression is a maximum unwanted signal level of −108 dBm per 5 MHz, not exceeded for more than 5% of any 1 hour period, with logarithmic scaling for other bandwidths (Schedule 2(1)-(2)).

• In-band versus out-of-band interference. The instrument treats in-band interference (same frequency band across geographic boundaries) and out-of-band interference (across frequency boundaries) differently. In-band interference management relies on device boundary criteria, core licence conditions and RALI procedures (s 8). Out-of-band interference is managed principally through compatibility requirements coupled with the notional receiver performance level because emission limits alone are an inadequate tool for close-proximity devices (s 9(1)-(4)).

• Register timing. The ACMA will only afford the protections described if receiver details were recorded in the Register before the relevant transmitter licence was first issued in the case of transmitter-licensed transmitters, or before the transmitter’s details were entered in the Register for spectrum-licensed transmitters (s 10(1)-(2)). This creates a chronological rule that affects entitlement to protection.

• Exclusions and special cases. Mobile devices are explicitly excluded from the compatibility requirement because itinerant devices cannot practically be managed under this fixed-receiver-focused requirement (s 11). Radiodetermination licences are treated differently for in-band interference: they are not required to follow the device boundary criterion if they instead implement measures to minimise impacts and, when not transient, must implement further mitigation measures (s 8(3)). Fixed licence point-to-multipoint systems are generally not required to meet the device boundary criterion and have coexistence arrangements in the Fixed Licence Determination and RALI MS 50 (s 8(4)).

• Receiver testing point. The instrument specifies that comparisons of sensitivity level and unwanted signal are to be defined at the antenna connector port of the receiver unit, so external filters and the receiving system are material to the measurement of compliance with the notional performance level (Schedule 1(3)).

Taken together, these concepts form a framework where: receivers that meet the notional performance benchmarks and are registered acquire an entitlement to protection; transmitters that create unwanted signals must comply with transmitter-side limits (the compatibility requirement and device boundary tests) unless they fall within specified exceptions; and the ACMA will apply these defaults in planning and dispute resolution unless parties agree alternative arrangements (s 7(6)).

The instrument designates particular legal and technical actors and changes their incentives and administrative tasks. The main affected parties are:

• Spectrum licensees operating in the 3.4 GHz band. These are the holders of 3.4 GHz spectrum licences and include those operating fixed receivers and fixed transmitters. They are the primary beneficiaries of the protections described, provided their receivers meet the notional performance level and are recorded in the Register in the prescribed timeframe (ss 5 definition of 3.4 GHz receiver; 10; 12).

• Transmitter licensees and apparatus licensees. Radiocommunications transmitters operated under transmitter licences are subject to device boundary criteria (as if they were area-wide licence transmitters in many cases, s 8(2)) and must consider the compatibility requirement when their transmitters could cause out-of-band interference to registered fixed receivers (s 13(1)). Apparatus licensees involved in planning and deployment will use the guidelines (s 7(5)).

• Class licence operators. The instrument provides protection against interference from devices operated under class licences and states that interference management frameworks for class-licensed devices are contained in the relevant class licence (ss 7(3)(a) and 8(6)). Class licence operators remain obliged to comply with their class licence conditions and may be constrained by coexistence arrangements in those instruments.

• Radiodetermination licence holders. These holders (for example, itinerant high-power radars) are explicitly not bound to the device boundary criterion in the same way as other transmitters, but they must implement measures to minimise impacts on 3.4 GHz spectrum licence receivers and, where interference is not transient, further mitigation measures are required (s 8(3)). The instrument recognises the transient, itinerant character of some defence and radiolocation operations.

• Department of Defence and national users of radiolocation. The instrument expressly notes the operation of high-power radiolocation services in the 3100-3500 MHz band and their potential to disrupt throughput, particularly uplink channels (s 9(5)). The Department is described as employing mitigation techniques, but occasions may arise where interference cannot be fully mitigated. The ACMA intends to work with the Department to provide additional information to assist spectrum licensees where appropriate (s 9(5)).

• ACMA. The Australian Communications and Media Authority is the decision-making and coordinating body that will apply the guidelines in planning, registration and interference resolution (s 7(5)-(6); s 3). The instrument is an advisory guideline under section 262 of the Act; ACMA uses these guidelines in exercising its regulatory powers and in conjunction with licence conditions and determinations (s 7(2)).

• Equipment manufacturers and network planners. Manufacturers and operators of equipment that will be used in the band must understand and, where necessary, design to the notional receiver performance metrics (Schedule 1) and the compatibility requirement (Schedule 2). The instrument sets minimum benchmarks that will influence equipment selection, filtering and network architecture.

Who pays and who decides. Practically, the compliance costs fall primarily on operators who either want protection or create interference. A spectrum licensee wishing to have a fixed receiver protected must ensure the receiver is registered and meets the notional performance level; the transmitter-side operator will need to comply with compatibility levels or device boundary tests or negotiate alternative arrangements (ss 10, 12, 13). The ACMA decides how the guidelines are applied in planning and in dispute resolution by reference to the Act, the section 145 Determination, and licence conditions (s 7(2), s 3).

Specific subsets of affected parties. Fixed licence (point-to-multipoint) operators are treated differently: they are generally not required to meet the device boundary criterion and their coexistence arrangements are set out in the Fixed Licence Determination 2025 and RALI MS 50 (s 8(4)). Mobile device operators are excluded from the compatibility requirement because the requirement is not usable for itinerant devices (s 11).

In short, the instrument creates a framework that affects licence holders, transmitter operators, equipment vendors and the ACMA. It imposes timing and performance-related obligations on parties seeking or claiming protection and creates practical obligations on potential interferers to meet compatibility limits or device boundary rules except where specific exemptions or alternative frameworks apply.

The instrument creates a set of duties for operators and corresponding practical entitlements for receivers that meet the stated conditions. These are expressed in the text; the key duties and rights are:

Duties placed on transmitter operators

• Ensure compliance with the compatibility requirement when a fixed receiver that is operated under a spectrum licence and satisfies the notional receiver performance level has been registered and is entitled to protection. Specifically, where subsection 13(1) applies, the licensee of a fixed transmitter under a transmitter or spectrum licence must ensure their transmitter meets the compatibility requirement in Schedule 2 (s 13(1); Schedule 2(1)). The compatibility requirement is a maximum unwanted signal level of −108 dBm per 5 MHz, not exceeded for more than 5% of any 1 hour period, with logarithmic scaling for other bandwidths (Schedule 2(1)-(2)).

• For in-band interference, meet core licence conditions and device boundary criteria. In-band interference caused by a transmitter under an adjacent spectrum licence is managed by: core conditions (s 66 of the Act), the device boundary criterion and deployment constraints in the section 145 Determination, recommended RALI coordination procedures, and any synchronisation requirement contained in the adjacent licence unless alternate arrangements are agreed (s 8(1)).

• For transmitters under transmitter licences first issued on specified dates, the device boundary criterion applies so they will be managed as if operated under an area-wide licence (s 8(2)). Conversely, the ACMA does not intend to protect receivers from in-band interference caused by transmitter-licensed transmitters first issued before certain dates (s 8(5)).

• Radiodetermination licence holders must implement measures to minimise impacts and, where interference is not transient, take further mitigation measures, rather than rely on the device boundary criterion (s 8(3)).

• Operators of class-licensed devices must comply with their class licence conditions, which may include interference management frameworks (s 13(5); s 8(6)).

Duties placed on spectrum licensees

• Record receiver details in the Register in the timeframes specified if they wish receivers to be afforded protection. A 3.4 GHz receiver will be afforded protection from a transmitter-licensed transmitter only if the receiver’s details were included in the Register before the relevant transmitter licence was first issued under section 100 of the Act (s 10(1)). For protection against a spectrum-licensed transmitter, the receiver details must have been included in the Register before the details of the relevant transmitter were included in the Register (s 10(2)).

• Where interference occurs between radiocommunications devices operated under 3.4 GHz spectrum licences, licensees may be required to synchronise their transmitters in accordance with any synchronisation requirement in a condition in the licence, unless alternative arrangements are agreed (s 13(3)).

Rights and entitlements accorded to registered receivers

• Registered fixed receivers that meet the notional receiver performance level are entitled to protection via the compatibility requirement and device boundary approaches set out in the instrument. The instrument sets the notional receiver performance level and requires that a receiver meet that level to gain protection (s 12(2); Schedule 1).

• The ACMA will assume that a receiver meets the notional performance level when considering whether to provide protection under this instrument; thus there is a procedural expectation that a receiver recorded in the Register will be treated as meeting the notional benchmarks for planning and dispute resolution (s 7(3)(c); s 12(2)).

Operational and procedural rights and duties

• The instrument permits parties to negotiate alternative protection requirements; it does not prevent negotiation and implementation of other protection arrangements between persons (s 7(6)).

• The instrument specifies measurement and test points: the comparison of sensitivity and unwanted signal is to be defined at the antenna connector port of the receiver unit, so measurements and verification should be conducted at that point (Schedule 1(3)).

Limitations and exclusions

• The compatibility requirement does not apply to mobile devices because of their itinerant nature (s 11).

• The compatibility requirement does not apply in relation to fixed transmitters operated under a radiodetermination licence (s 13(4)).

Administrative duty of the ACMA

• The ACMA is to use these guidelines in planning and resolution of interference and to provide guidance to licensees, apparatus licensees and authorised third parties (s 7(5)). The instrument is advisory but will be used by ACMA as a reference in decisions about protection and coordination.

In practical terms, the duties shift planning and mitigation costs onto transmitter-side operators who wish to deploy in the vicinity of registered fixed receivers that meet the notional performance level, while registered receiver owners gain a practical entitlement to protection from properly coordinated transmitters. The duty to register receivers in advance creates an administrative cost and a timing constraint that affects who obtains protection.

The instrument is an advisory guideline made under section 262 of the Act and does not itself prescribe statutory penalties in its text. However, the guidelines function within a regulatory framework where enforceable licence conditions, determinations and ACMA powers operate. The document sets out how ACMA expects interference to be managed and the factual criteria it will apply. The enforcement and consequence mechanics are therefore indirect and mediated through other enforceable instruments and regulatory decisions. Key enforcement-related points in the instrument are:

• Advisory status and legal authority. The instrument is expressly made under section 262 of the Act (s 3). As an advisory guideline it provides guidance on management and settlement of interference and is intended for use by spectrum licensees, apparatus licensees and authorised third parties in planning and resolution (s 7(4)-(5)). Advisory guidelines are not themselves licence conditions. The practical enforcement consequence is that the ACMA will use them when exercising its regulatory powers and in applying licence conditions and determinations.

• Reliance on enforceable licence conditions and determinations. The instrument repeatedly references enforceable elements of the Act and other legislative instruments. For example, emission buffer zones are created by core licence conditions under section 66 of the Act (s 7(2)(a)); unacceptable levels of interference and registration of radiocommunications devices are managed by a section 145 determination (s 7(2)(b)); and licences issued under section 100 are the legal vehicle for transmitter licences (s 10). Where a licence condition or a section 145 determination imposes an obligation, failure to comply with that condition can carry the enforcement consequences provided in the Act and the relevant instrument. The guidelines therefore operate as a practical map of how enforceable requirements will be applied.

• ACMA’s treatment of protection as contingent on registration. The instrument creates a procedural entitlement: the ACMA will only afford the protections set out in the guidelines if the receiver was registered in the Register before the relevant transmitter licence was issued or the transmitter’s details were registered (s 10(1)-(2)). Practically, the enforcement outcome for failing to register in time is denial of protection rather than an immediate statutory fine specified in this instrument.

• Compliance with compatibility requirements and device boundary criteria. The instrument requires transmitters to meet the compatibility requirement for protected receivers (s 13(1)). While the guideline itself does not set criminal fines, compliance with licence conditions , for example device boundary criteria encoded in the section 145 determination or core licence conditions under section 66 , can be enforced under the Act. The guidelines point to those sources as the mechanisms through which non-compliance will be managed.

• Radiodetermination and class licence exceptions. Radiodetermination licence holders are not required to follow the device boundary criterion in the same way but are required to implement mitigation measures and further mitigation if interference is not transient (s 8(3)). Class licence compliance is required under the class licence terms (s 13(5)). The instrument therefore shifts the locus of enforcement to the relevant licence terms and to the ACMA’s ordinary regulatory powers.

• No new penalty regime created. The instrument does not create a new penalty regime or expressly amend enforcement powers; it operates by specifying how ACMA will use existing powers, licence conditions and determinations to manage interference. For practitioners, the enforcement risk is therefore contextual and depends on the interplay between these guidelines and the enforceable statutory instruments they reference.

In short, enforcement occurs via existing statutory tools: licence conditions, the section 145 determination, the Register and ACMA’s regulatory actions. The guideline changes how the ACMA will interpret and apply those tools in the 3.4 GHz band by setting default performance assumptions, registration timing rules and numerical compatibility thresholds that guide coordination and dispute resolution.

This instrument is explicitly drafted to sit within the wider radiocommunications legislative and administrative framework and it cross-references several other legislative instruments and determinations. The key interactions are:

• The Act and ACMA powers. The instrument is made under section 262 of the Act (s 3). It relies on and references statutory powers and processes in the Act, notably section 66 (core licence conditions) and section 145 (unacceptable levels of interference and registration of radiocommunications devices) as legal bases for measures used to create emission buffer zones and device boundary criteria (s 7(2)(a)-(b); s 8(1)(b)). In practice this means the guideline does not replace or override core licence conditions or determinations, but explains how ACMA will apply them and what assumptions it will use in the 3.4 GHz context.

• Section 145 Determination. The device boundary criterion for 3.4 GHz spectrum-licensed transmitters is defined in the Radiocommunications (Unacceptable Levels of Interference - 3.4 GHz Band) Determination 2025 (the section 145 Determination) and the guidelines instruct users to consult that determination for device boundary and deployment constraints (s 5 definition; s 8(1)(b)). The section 145 Determination is an enforceable legal instrument and the guidelines indicate that device-boundary obligations found there will be used to manage in-band interference.

• Core licence conditions under section 66 of the Act. Emission limits and out-of-area/out-of-band emission limits are often implemented as core licence conditions under section 66 (s 7(2)(a)). The guidelines indicate these limits are one of the tools that create emission buffer zones, but they also explain the limitations of emission limits for close-proximity out-of-band interference (s 9(1)-(4)).

• RALI MS 47 and RALI MS 50. The instrument references Radiocommunications Assignment and Licensing Instructions MS 47 and MS 50 for coordination procedures and device boundary tests for transmitter licences and point-to-multipoint fixed licences respectively (s 5 definition; s 8(1)(b),(4)). RALI instruments are administrative implementation instruments used by ACMA; the guidelines direct users to them and treat them as part of the operational toolkit.

• Radiocommunications Licence Conditions (Fixed Licence) Determination 2025. The instrument notes coexistence arrangements for fixed licence point-to-multipoint systems are set out in the Fixed Licence Determination and RALI MS 50 (s 8(4)). Those determinations are enforceable and contain specific licence conditions that interact with the guidelines.

• Class licences. The guidelines state that interference management frameworks for class-licensed devices are contained in the relevant class licence (s 8(6)). Class licences are separate instruments and the guidelines do not override those conditions.

• The Radiocommunications (Interpretation) Determination 2025 and related interpretation instruments. Section 5 imports terms from the Radiocommunications (Interpretation) Determination 2025 and other interpretation instruments replacing it, for terms such as area-wide licence and radiodetermination licence (s 5(2)-(3)). This means conceptual terms used in the guideline are to be read alongside the definitions in those interpretation determinations.

• Repeal of prior guidelines. The 2015 advisory guidelines are expressly repealed (s 4). That removes the earlier advisory framework and replaces it with the 2025 approach; users should therefore rely on these guidelines in planning going forward.

Practical consequences of these interactions

• Advisory status in relation to enforceable instruments. The guidelines instruct and influence coordination, but they do not supersede enforceable licence conditions or determinations. In conflict, an enforceable provision in a licence or a determination (for example, device-boundary constraints in the section 145 Determination, core conditions under section 66, or conditions in the Fixed Licence Determination) will control the legal rights and enforcement outcomes. The guidelines provide the ACMA’s intended approach where the enforceable instruments are applied.

• Timing and registration rules interface with licence issuance. The Register timing rules in section 10 tie ACMA’s practical protection outcomes to statutory licence issuance under section 100 of the Act and the Register. That directly links an administrative register requirement to entitlement to protection in licence coordination and dispute resolution.

• Technical standards referenced from external standards bodies. Several numerical values are referenced to 3GPP TS 38.104 tables (Schedules 1 and 4). Those external standards are not themselves domestic legislation, but the guidelines import their values as benchmarks. Practitioners must therefore map equipment specifications and test reports to the referenced 3GPP values when implementing these guidelines.

Overall, the instrument is a coordination layer that sits above and alongside enforceable legal instruments. It shapes ACMA’s expectations and the practical bargaining positions of licence-holders, but enforcement depends on the Act, determinations (including the section 145 Determination), licence conditions and RALI instruments.

This instrument contains a limited and explicit amendment history within its text. The principal elements are:

• Repeal of the 2015 guidelines. Clause 4 repeals the Radiocommunications Advisory Guidelines (Managing Interference to Spectrum Licensed Receivers - 3.4 GHz Band) 2015 (F2015L00729) (s 4). There is no other repeal or amendment provision within the instrument, so the previous advisory framework is displaced and replaced by the 2025 guidelines as of commencement.

• Commencement. The instrument commences on 23 September 2025 (s 2). That date is the operational date for the guidelines; from that date the 2015 instrument is repealed and the 2025 instrument is the applicable advisory guidance.

• Authority and sources. The instrument is made under section 262 of the Act (s 3). It references a number of other instruments and determinations which may themselves be amended over time and which the guidelines treat as references to those instruments as in force (s 6). Section 6 provides that references to other legislative instruments in this instrument are to those instruments "as in force from time to time", meaning that subsequent valid amendments to referenced instruments will be taken into account when applying the guideline.

• Cross-references to instruments that may be replaced. The definitions in section 5 explicitly anticipate replacement or amendment of other instruments. For example, the definition of "fixed licence (point to multipoint system)" refers to the Radiocommunications Licence Conditions (Fixed Licence) Determination 2025 or any instrument that replaces it (s 5). Similarly, subsection 5(2) looks to the Radiocommunications (Interpretation) Determination 2025 or any replacement instrument for certain terms.

Absent from the instrument is any schedule of prior amendments to this instrument itself or any transitional savings clauses other than the timing rules for registration and protection (s 10). The instrument provides detailed transitional mechanics relevant to protection eligibility , for example, a receiver must be recorded in the Register before the relevant transmitter licence is first issued to be afforded protection from transmitter-licensed transmitters (s 10(1)) , but it does not lay out a broad array of transitional exemptions beyond those specific timing rules.

For practitioners, the immediate amendment-relevant points are: the 2015 guidelines are formally repealed as of commencement; other referenced instruments may be amended and those amendments will be treated as in force for application of the guidelines (s 6); and users should watch for future amendments to the section 145 Determination, the Fixed Licence Determination, RALI MS 47, RALI MS 50 and the Radiocommunications (Interpretation) Determination because those instruments provide binding operational detail that the guidelines reference and expect to be current.

The text of the instrument does not include any litigation history. It cites no judicial decisions or administrative determinations arising from litigation. The instrument does reference other legislative and technical instruments and international technical standards (for example, 3GPP TS 38.104) as sources for numerical values, but it does not discuss any disputes or court decisions concerning the application or interpretation of these advisory guidelines.

Because the instrument is an advisory guideline rather than a statute that itself creates offences or a determination setting out enforceable licence conditions, the guideline does not record legal challenges or appeals against it. Any litigation or administrative disputes that arise in practice are likely to engage the Act, licence conditions, the section 145 Determination or ACMA’s exercise of statutory powers, rather than the advisory guideline in isolation. The instrument does not provide a record of such matters.

Practitioners seeking litigation history will need to search decisions under the Act, ACMA administrative determinations, and any relevant judicial review proceedings or merits review actions that involve application of the Act, licence conditions, or the section 145 Determination. The instrument itself provides the framework that ACMA will use for planning and dispute resolution, but it does not specify or summarise any adjudicative outcomes.

The instrument contains a number of practical traps and timing, measurement and scope points that can produce unintended surprises if overlooked. These are concrete, source-grounded gotchas practitioners should note:

• Registration timing determines entitlement to protection. Section 10 imposes a strict chronological rule: a 3.4 GHz receiver will be afforded protection from a transmitter-licensed transmitter only if its details were included in the Register before the relevant transmitter licence was first issued (s 10(1)). For protection from a spectrum-licensed transmitter, the receiver details must have been included in the Register before the transmitter’s details were included in the Register (s 10(2)). Failure to register in the correct sequence can result in denial of protection irrespective of later registration.

• Mobile devices are excluded from the compatibility requirement. The compatibility requirement in Part 5 does not apply to receivers that are mobile devices because their itinerant nature makes the requirement impractical (s 11). If a network relies on protection for mobile user equipment, those expectations are misplaced; the guideline expressly excludes that class of device from the compatibility regime.

• ACMA assumes notional receiver performance levels. The ACMA will assume a receiver meets the notional performance level when considering protection (s 7(3)(c); s 12(2)). That creates a default administrative assumption that can be overridden only by alternative arrangements , but an operator cannot rely on this assumption if the receiver, in fact, does not meet the notional benchmarks and a dispute requires verification. The notional sensitivity reference points are specific: −96 dBm measured within a 5 MHz rectangular bandwidth for receivers with bandwidth ≤20 MHz, and −89 dBm measured within a 20 MHz rectangular bandwidth for receivers with bandwidth >20 MHz (Schedule 1(2)).

• Compatibility requirement applies only to qualifying fixed receivers. Two preconditions must be met before subsection 13(1) applies: the receiver must be a fixed receiver operated under a spectrum licence, it must have at least the notional receiver performance level, and it must have been included in the Register before the relevant transmitter was registered or licensed (s 13(2)). If any of those conditions are missing, the transmitter’s duty under s 13(1) may not be triggered.

• Device boundary criterion exceptions. Several categories of transmitter are treated differently. Radiodetermination transmitters are not required to follow the device boundary criterion in RALI MS 47 if they implement measures to minimise impact, but they must take further mitigation steps where interference is not transient (s 8(3)). Fixed licence (point-to-multipoint) transmitters are generally not required to meet the device boundary criterion and are instead subject to coexistence arrangements in the Fixed Licence Determination and RALI MS 50 (s 8(4)). These exceptions can produce different obligations and negotiation positions for parties at multi-operator sites.

• Out-of-band interference unpredictability. The instrument recognises that out-of-band interference is difficult to predict and that emission limits cannot practically protect devices in close proximity (s 9(1)-(3)). This means that simply meeting declared emission limits does not guarantee that a transmitter will not cause harmful interference to nearby receivers; close-proximity coordination and adherence to the compatibility requirement and receiver performance benchmarks are necessary.

• Defence radar interference risk. The instrument explicitly notes the potential for Department of Defence radiolocation services operating in 3100-3500 MHz to disrupt 3.4 GHz receivers and that mitigation may not always be possible (s 9(5)). It also states that ACMA may only provide additional information to existing or likely prospective spectrum licensees, which can be a limitation for new entrants seeking detailed situational awareness.

• Measurement point and inclusion of external filters. Schedule 1(3) specifies that performance comparisons are to be defined at the antenna connector port of the receiver unit. Therefore external filters and the entire receiving system are relevant to whether a receiver meets the notional performance parameters. If a party assumes that the receiver unit alone meets the performance level without considering the external feeder and filter losses, they risk an incorrect conclusion.

• Default antenna gain if not recorded. The Register’s antenna gain and feeder loss values should be used for coordination; if an antenna gain or feeder loss are not specified in the Register, a default antenna gain (including losses) of 17 dBi in all directions must be used (Schedule 1(5)). This default can materially affect protection calculations and coordination footprints if no site-specific antenna data is recorded.

• Numerical thresholds and scaling. The compatibility requirement is expressed as −108 dBm per 5 MHz, not exceeded for more than 5% of any 1 hour period, with logarithmic scaling to other bandwidths (Schedule 2(1)-(2)). Practically, parties must implement correct logarithmic scaling for bandwidths that differ from 5 MHz; the instrument does not provide worked numeric conversions. Incorrect scaling can lead to under- or over-estimation of allowable unwanted-signal levels.

• Synchronisation conditions. Where interference is caused between radiocommunications devices operated under 3.4 GHz spectrum licences, synchronisation requirements in licence conditions may be imposed unless alternative arrangements are agreed (s 8(1)(c); s 13(3)). Parties should be aware that licence conditions may impose synchronisation obligations that effectively constrain network timing, planning and equipment selection.

These are mechanical, source-proximate risks and constraints. They translate into negotiation points, technical retrofit costs (filters, antenna changes), administrative steps (Register updates) and potential strategic disadvantages if parties fail to plan for the registration and performance-verification steps set out in the instrument.

This section sets out a practical compliance checklist and recommended sequence of steps grounded in the instrument’s provisions. It focuses on actions for spectrum licensees, transmitter licensees, class licence operators and equipment vendors.

1. Determine device class and registration status

   • Confirm whether each receiver is a fixed receiver operated under a 3.4 GHz spectrum licence or a mobile device (ss 5 definition; 11). The compatibility requirement in Part 5 applies only to fixed receivers; mobile devices are excluded (s 11).
   • Ensure the receiver’s details are recorded in the ACMA Register in the correct order relative to the transmitter’s licence or registration, because protection depends on registration timing (s 10(1)-(2)). For transmitter-licensed transmitters, receivers must be in the Register before the transmitter licence is first issued; for spectrum-licensed transmitters, receivers must be in the Register before the transmitter details are included in the Register.

2. Verify receiver meets the notional receiver performance level

   • Ensure the receiver meets the notional receiver performance metrics in Schedule 1: adjacent channel selectivity, intermodulation response rejection and receiver blocking, each relative to the notional sensitivity reference points (Schedule 1(1)-(3)). The notional sensitivity reference points are −96 dBm in 5 MHz for receiver bandwidths ≤20 MHz and −89 dBm in 20 MHz for bandwidths >20 MHz (Schedule 1(2)).
   • Conduct measurements at the antenna connector port of the receiver unit, because Schedule 1(3) requires comparisons at that point, and external filters and the whole receiving system are included in the performance evaluation.
   • Ensure antenna gain and feeder loss are recorded in the Register. If not specified, default to 17 dBi for coordination purposes (Schedule 1(5)).

3. Plan transmitter deployment to meet device boundary criteria and compatibility requirement

   • For in-band interference, apply the device boundary criterion and deployment constraints in the section 145 Determination (s 8(1)(b)). For transmitters under transmitter licences issued on or after specified dates, apply the device boundary criterion as if the transmitter were an area-wide licence (s 8(2)).
   • Where protection is sought for a fixed receiver, design transmitters to meet the compatibility requirement in Schedule 2: a maximum unwanted signal level of −108 dBm per 5 MHz not exceeded for more than 5% of any 1 hour period, scaled logarithmically for other bandwidths (Schedule 2(1)-(2)). Perform accurate scaling calculations for transmitter bandwidths different from 5 MHz.
   • If operating adjacent to other 3.4 GHz spectrum licensees, check licence conditions for any synchronisation requirement and be prepared to negotiate alternative arrangements (s 8(1)(c); s 13(3)).

4. For radiodetermination and fixed licence (point-to-multipoint) operators

   • Radiodetermination operators should implement measures to minimise the impact on 3.4 GHz spectrum licence receivers and be prepared to implement further mitigation measures if interference is not transient (s 8(3)).
   • Fixed licence (point-to-multipoint) operators should consult the Radiocommunications Licence Conditions (Fixed Licence) Determination 2025 and RALI MS 50 for coexistence arrangements (s 8(4)). Do not assume the device boundary criterion applies in the same way as for area-wide licences.

5. Document and retain verification evidence

   • Maintain test reports demonstrating that a receiver meets the notional performance thresholds, with measurements at the antenna connector port as required (Schedule 1(3)). Keep system-level records that include external filter performance and feeder losses.
   • Record antenna gain and feeder loss in the Register; if the Register lacks these entries, coordination will default to an antenna gain of 17 dBi (Schedule 1(5)).

6. Take account of out-of-band interference unpredictability

   • Recognise that emission limits alone may not protect devices in close proximity and that additional radio-frequency filtering, network redundancy, or resilient network configuration may be necessary to mitigate interference, including potential interference from defence radars (s 9(1)-(5)). Build redundancy and filtering into network designs where vulnerability to out-of-band emissions exists.

7. Use RALI and ACMA guidance in coordination

   • Follow the recommended preliminary coordination procedures in Part 8 of the Radiocommunication Advisory Guidelines (Managing Interference from Spectrum Licensed Transmitters - 3.4 GHz Band) 2025, and apply RALI MS 47 and RALI MS 50 where they are referenced as the administrative procedure for device boundary placement and coordination (s 8(1)(c); s 5 definitions).
   • If in doubt, seek information and guidance from the ACMA. Note that ACMA intends to work with the Department of Defence to provide additional information to assist spectrum licensees on defence radar matters, and that such information will generally be given directly to existing or prospective spectrum licensees (s 9(5)).

8. Negotiate alternative arrangements where appropriate

   • The instrument does not prevent negotiation of alternative protection arrangements between parties (s 7(6)). If equipment cannot meet the notional receiver performance level or the compatibility requirement is impractical, document any negotiated alternative arrangements and ensure they are recorded and accepted by affected parties, and where necessary by ACMA.

9. Monitor for changes to referenced instruments

   • The guidelines treat references to other legislative instruments as references to those instruments as in force from time to time (s 6). Monitor changes to the section 145 Determination, Radiocommunications Licence Conditions (Fixed Licence) Determination, RALI MS 47, RALI MS 50, and the Radiocommunications (Interpretation) Determination 2025, because those instruments carry enforceable obligations and operational detail that will affect compliance.

10. Prepare for dispute resolution and ACMA engagement

    • Keep records that substantiate registration timing, measurement methods and results, antenna and feeder data, and any coordination attempts or synchronisation agreements. These will be the core evidence relied on in ACMA planning and interference-resolution processes (s 7(5)).

Checklist summary

• Register fixed receivers in the Register before the relevant transmitters are issued or registered (s 10).
• Verify receiver performance to the notional levels at the antenna connector port and record measurements (Schedule 1(3); s 12).
• Record antenna gain and feeder loss in the Register or accept the 17 dBi default for coordination (Schedule 1(5)).
• Ensure transmitters meet the compatibility requirement when applicable and apply the device boundary criterion where required (s 13; Schedule 2; s 8).
• For radiodetermination and fixed licence operators follow the separate mitigation/coexistence procedures set out in the relevant determinations and RALIs (s 8(3)-(4)).

Following these steps aligns operational practices with the instrument’s requirements and the ACMA’s stated expectations, while preserving the ability to negotiate alternate arrangements where technically and commercially feasible (s 7(6)).