Radiocommunications (Unacceptable Levels of Interference – 3.4 GHz Band) Determination 2025

The Determination organises a few tightly defined technical concepts and ties them to legal consequence. Those core concepts are device boundary, device boundary criterion, RP, MP (including PL, LOP and Gr), propagation loss calculation rules, earth station protection zones and urban areas.

Device boundary and construction method

• The device boundary is the locus of end points on radials drawn at one degree intervals (σn = 0 to 359) from the transmitter, found by evaluating the device boundary criterion at m × 100 metre increments for m = 2 to 1010 and selecting the first increment where RP - MP ≤ 0, or where m = 1010 if the criterion never becomes ≤ 0 (Schedule 1, item 1). Practically, that means checks begin at 200 metres and extend out to a hard cap of 101,000 metres on each radial.

Device boundary criterion RP - MP

• RP is horizontally radiated power in dBm EIRP per MHz for each bearing σn (Schedule 1, item 2).
• MP is defined as PL(lmn, Lmn) + LOP - Gr, where PL is propagation loss at the increment, LOP is the level of protection, and Gr is the nominal receiver antenna gain (set to 0 dBi including feeder loss) (Schedule 1, item 2).
• Two LOPs are specified: for transmitters that incorporate an AAS the LOP is −90 dBm per MHz, and for all other transmitters it is −98 dBm per MHz (Schedule 1, item 2). The instrument expressly notes that for a transmitter with AAS the RP is defined as the sum of antenna gains toward the horizontal plane and towards azimuth σn plus total radiated power in dBm, reflecting an assumption about dynamic control of beam pointing or power (Schedule 1, item 2, Note 1).

Propagation loss modelling

• For antennas above 6 m above ground, PL is calculated using methods and parameters in ITU‑R P.525-4 (free-space attenuation) and ITU‑R P.526-15 (diffraction) (Schedule 1, item 3(1)(a)). For antennas at or below 6 m, PL uses P.525-4, P.526-15 and P.2108-0 (clutter loss) (Schedule 1, item 3(1)(b)).
• The Determination specifies path profile development at 100 m increments (Schedule 1, item 3(3)(a)) and fixes receiver nominal height at 5 m above ground for P.526-15 calculations (Schedule 1, item 3(2)(a)). When P.2108-0 is used, the percentage of locations is set to 0.08%, the correction is applied at one end only, and the correction is floored at 0 dB and capped at 8 dB (Schedule 1, item 3(4)).

Groups, antenna height measurement and accuracy

• For groups of transmitters, RP for each bearing is taken to be equal across the group and equal to the maximum horizontally radiated power in any direction of any transmitter in the group (Schedule 1, item 1(2)).
• Antenna height is the vertical height of the antenna phase centre measured relative to the lowest elevation point on the line where the supporting structure meets ground or sea, measured to a tolerance of less than 5 parts in 100 (Schedule 1, item 4(1)). For groups the height is the greatest of the individual heights (Schedule 1, item 4(2)).
• Section 8 imposes a 95 percent confidence requirement on the estimation of parameters in Schedule 1 unless otherwise specified, meaning parameter estimates used in the device boundary calculation must be statistically conservative to the extent that there is at least 95 percent confidence the true value will remain below the requirement.

Geographic exceptions and zones

• s 7 establishes that portions of the device boundary lying outside the geographic area of the licence generally render interference unacceptable, but enumerates exceptions where such parts are not unacceptable: where the part lies outside the Australian Spectrum Map Grid and is connected to an allowed radial (s 7(2)); where it lies inside an earth station protection zone and meets radial connectivity and non-crossing conditions (s 7(3)); where it lies outside the geographic area but the connecting radial does not cross certain areas of land permanently above the territorial sea baseline and does not cross specific HCIS identifiers (s 7(4)); and where it lies inside an urban area and the transmitter occupied bandwidth is within 3400-3475 MHz and radial connectivity/non-cross conditions apply (s 7(5)). Schedules 2 and 3 list earth station protection zones and urban areas by HCIS identifiers.

Transitional treatment

• s 9 preserves the applicability of the 2015 Determination for transmitters recorded in the Register before commencement, except where a registered detail changes and the new device boundary is not greater than the old on each radial; in that circumstance a level of interference which would otherwise be unacceptable is not unacceptable because of that change (s 9(2)-(3)).

Taken together, these components translate RF engineering inputs (EIRP per MHz, antenna gain and height, terrain/clutter profiles, AAS behaviour) into legally significant boundaries that determine whether a transmitter's emissions are allowable in a particular geographic area.

The principal legal subjects affected by this Determination are holders of 3.4 GHz spectrum licences, operators of radiocommunications transmitters covered by those licences, prospective licensees and the Australian Communications and Media Authority (ACMA) as the decision maker applying the Register‑related consequences. The instrument expressly defines "3.4 GHz spectrum licence" and "3.4 GHz band" (s 5), so the rules apply only to transmitters operated under such licences.

Specific affected parties and practical effects:

• 3.4 GHz licence holders and operators: They must ensure transmitters do not cause unacceptable interference as defined in s 7. That requires calculating device boundaries in accordance with Schedule 1, controlling RP (horizontally radiated power in dBm EIRP per MHz), measuring antenna height as specified (Schedule 1, item 4), and ensuring that device boundaries lie within their geographic licence area except where specific exceptions in s 7(2)-(5) apply. If the device boundary cannot be calculated per Schedule 1 the transmitter is treated as unacceptable (s 7(1)(c)).
• Operators of AAS-equipped transmitters: The Determination contains particular provisions for transmitters that incorporate an AAS. For such transmitters RP is described with reference to gains in the horizontal plane and azimuth plus total radiated power, and the LOP is set to −90 dBm per MHz rather than −98 dBm per MHz for non‑AAS transmitters (Schedule 1, item 2, Notes and LOP definition). The instrument also records an assumption that beam pointing or power can be dynamically controlled to ensure RP is not exceeded (Schedule 1, item 2, Note 1). That places a different technical compliance profile, and different exposure, on AAS operators compared to conventional antenna systems.
• Groups of transmitters: The device boundary calculation treats a group as having RP equal across bearings and equal to the maximum horizontally radiated power of any member of the group (Schedule 1, item 1(2)). Groups must therefore coordinate to the maximum emitter in the group for boundary calculation purposes.
• ACMA: The Determination is made under subsection 145(4) of the Act (s 3). The instrument feeds directly into ACMA's administrative judgments about whether to include transmitter details in the Register or to take measures under s 145(1), as noted by the instrument (s 7 Note). ACMA therefore must apply the technical rules, maintain mapping and HCIS data, assess radial crossing over other licences, and apply the transitional rules in s 9.
• Owners/operators of earth stations inside protection zones listed in Schedule 2: The Determination identifies earth station protection zones where, if a part of a device boundary lies inside such a zone and meets the radial connectivity/non‑crossing conditions, that part is not treated as unacceptable (s 7(3) and Schedule 2). This creates a spatially concentrated grouping of interests.
• Licensees whose transmitters were included in the Register before commencement: They are subject to the transitional arrangements in s 9 which continue to reference the 2015 Determination as the benchmark for whether their transmitter is unacceptable, unless they make changes to registered details that affect the device boundary in a way that is not covered by s 9(3).
• Parties exempt from registration under s 69(2) of the Act: The instrument notes that some transmitters exempt from Register requirements under their licence are not required to meet the device boundary criterion in this instrument (s 7 Note). Those exempt transmitters therefore fall outside the operational effect of the device boundary calculation even though they operate under the same spectrum licence class.

Collateral technical and commercial stakeholders will also be affected:

• Equipment manufacturers and network designers, because RP, antenna height and EIRP/MHz parameters determine design requirements and may influence product choices (for example AAS capabilities and power control).
• Consultants and compliance teams, because the 100 metre increment profiles, the 95 percent confidence accuracy requirement (s 8), and the use of specific ITU‑R methods mean that technical models, measurement campaigns and statistical analyses will be necessary to demonstrate compliance.
• Nearby or overlapping licence holders, because s 7(2)-(5) includes explicit non‑crossing conditions related to other 3.4 GHz licences; mapping and spatial analysis will determine whether radials cross other licence geographic areas.

The Determination thus allocates compliance and verification tasks mainly to licence holders and ACMA, with distinct technical obligations for AAS operators and group operators, and grants limited spatial carve outs for earth station zones and specified urban/HCIS areas.

This Determination imposes duties on licence holders and confers procedural rights that flow from the Register and transitional arrangements. The duties are primarily technical and documentary. The rights and protective measures arise from transitional provisions and specific exceptions.

Primary duties

• Duty to avoid unacceptable interference: Licence holders must prevent operation of transmitters that cause a level of interference deemed unacceptable under s 7. This includes avoiding contravention of core licence conditions about maximum permitted radio emission outside authorised spectrum or geographic area (s 7(1)(a)(i)-(ii)).
• Duty to calculate device boundary per Schedule 1: Licence holders must calculate the device boundary in the manner set out in Schedule 1 where registration is relevant. If the device boundary cannot be calculated in accordance with item 1 of Schedule 1 the interference is, by operation of s 7(1)(c), unacceptable.
• Duty to estimate parameters with sufficient statistical confidence: Unless otherwise specified, values of parameters in Schedule 1 must be estimated with at least 95 percent confidence that the true value will remain below the requirement specified (s 8). This imposes an evidentiary and modelling duty on licensees and their technical advisers.
• Duty to measure antenna height to specified tolerance: Antenna height for the purposes of propagation calculations must be measured as the vertical height of the phase centre relative to the supporting structure's lowest elevation point as described, with measurement error less than 5 parts in 100 (Schedule 1, item 4(1)).
• Duty for groups: For groups of transmitters the RP used in calculations is set equal across bearings and to the maximum horizontally radiated power of any transmitter in the group, which imposes coordination or conservative design obligations on grouped operations (Schedule 1, item 1(2)).

Operational/administrative duties arising from interactions with the Register and ACMA

• Duty to maintain accurate Register entries: Changes to registered details can interact with transitional protection in s 9. If a registered change has the new device boundary distances on each radial equal to or less than the old ones, then the immediate post-change interference is not unacceptable because of the relevant change (s 9(3)). This creates a duty to ensure that recorded changes are technically analysed before being entered.
• Duty to ensure radial connectivity/non‑crossing conditions for exceptions: Several exceptions to the device boundary geographic rule require that the out‑of‑area part be connected to a radial mentioned in item 1 of Schedule 1 and that the radial does not cross over the geographic area of another 3.4 GHz licence (s 7(2)-(5)). This places mapping and spatial analysis obligations on licensees and ACMA.

Rights and protective rules

• Transitional right to previous standard: Transmitters included in the Register before commencement retain protection under the 2015 Determination for the purpose of s 145(4) unless specified changes are made (s 9(2)). That is a temporally bounded right that preserves prior expectations for pre‑existing registrants.
• Exceptions that narrow the geographic‑area constraint: The instrument enumerates factual circumstances in which parts of the device boundary lying outside a licence area are not unacceptable (s 7(2)-(5)). These exceptions are rights‑like in that they prevent immediate classification of interference as unacceptable in defined spatial circumstances, for example where the out‑of‑area part lies within an earth station protection zone (s 7(3), Schedule 2).
• AAS-specific treatment: The instrument treats AAS-equipped transmitters differently in the device boundary criterion and in LOP (Schedule 1, item 2). That is a differential regulatory outcome that AAS licence holders can rely on, but it is coupled to an operational assumption about dynamic control (Schedule 1, item 2, Note 1).

Consequences and administrative enforcement

• The Determination feeds into ACMA’s ability to refuse to include transmitter details in the Register where operation could cause unacceptable interference, as referenced in its own notes (s 7 Note). The Determination therefore changes licence compliance profiles and the administrative basis for ACMA actions under s 145 of the Act.

These duties are technical, continuous and evidence‑based. The rights are mainly transitional and conditional on meeting technical or spatial criteria. The Determination places the onus on licence holders to generate and maintain the technical evidence required for correct device boundary determination and to design or control their transmitters to keep RP - MP ≤ 0 within their authorised geographic area, except where exceptions apply.

The Determination itself does not create new criminal or civil penalties in express terms. Instead it redefines what counts as an "unacceptable level of interference" for the operation of ACMA’s statutory powers under the Act and thereby affects administrative enforcement outcomes. The legal authority cited is subsection 145(4) of the Act (s 3), and the instrument’s notes explicitly link the Determination to ACMA’s power under subsection 145(1) to refuse to include transmitter details in the Register if the operation could cause unacceptable interference (s 7 Note). Readers should therefore treat the Determination as creating adjudicative and regulatory triggers rather than standalone sanctions.

Enforcement mechanisms implicit in the instrument and the Act‑linked notes

• Refusal of registration: The primary operational enforcement mechanism is ACMA’s ability to refuse to include a transmitter in the Register where it would cause unacceptable interference (s 7 Note, s 9). Refusal to register may prevent a transmitter from claiming certain licence protections or exercising rights that flow from registration under the Act. The Determination makes failure to be able to calculate a device boundary a ground for an "unacceptable" finding (s 7(1)(c)), which directly supports registration refusal.
• Administrative compliance action: While the Determination does not list sanctions, classifying interference as unacceptable under s 7 triggers ACMA’s statutory functions under Part 5 and other parts of the Act (the instrument references the Act and interpretation instruments in ss 5 and 6). In practice, that can lead to directions, notices, variation or suspension of spectrum licences or other administrative measures under the Act; the instrument itself, however, does not spell out those measures.
• Spatial and technical enforcement: The device boundary calculation is prescriptive and verifiable. Enforcement will therefore be technical: ACMA will assess RP, PL, LOP, Gr, antenna height and the path profile at 100 metre intervals using the specified ITU‑R procedures (Schedule 1, items 1-3). The 95 percent confidence requirement in s 8 creates an evidentiary standard for parameter estimation that licensees must meet when defending their technical assessments.

Enforcement levers and evidentiary burdens

• Mapping and HCIS evidence: Enforcement will rely on mapping evidence (Australian Spectrum Map Grid, HCIS identifiers) and spatial analysis to determine whether radials cross other licences or land permanently above the territorial sea baseline (s 7(2)-(5), Schedule 2-3). Disputes will centre on whether radials are properly identified and whether the conditions for exceptions apply. The Determination requires ACMA and licensees to use the HCIS identifiers listed in the Schedules.
• Technical model adherence: Because the Determination prescribes ITU‑R methods and parameters, an enforcement action will hinge on whether the required models were applied and whether parameter estimation met the 95 percent confidence rule (s 8). If a licensee’s model diverges from the specified procedures, ACMA’s technical model will prevail for the administrative determination.
• Antenna height measurement tolerances and phase centre definition: Enforcement may turn on precise measurement protocols, given the 5 parts in 100 tolerance requirement for antenna height measurement (Schedule 1, item 4(1)). Errors in measuring the phase centre or in locating the supporting structure relative to ground could change PL outcomes materially in some cases.

Practical implication: the Determination transforms technical non‑compliance into administrative non‑registration or other ACMA action. The instrument’s design allocates enforcement responsibility to the ACMA’s technical and spatial verification capabilities. The instrument itself does not prescribe monetary penalties or criminal offences; it sets objective technical thresholds that make administrative remedies available under the Act when breached.

This Determination is a legislative instrument made under subsection 145(4) of the Radiocommunications Act (the Act) (s 3). It is explicitly framed to work with other instruments and statutory provisions, and it relies on definitions and procedures from related instruments. The Determination therefore interacts with the broader radiocommunications regulatory framework in the following ways.

Dependent definitions and cross‑references

• The Determination imports defined terms from the Act and from technical interpretation instruments, as stated in s 5 and s 6. It refers to the Act for definitions such as ACMA, core condition, frequency band, interference, radiocommunications device, radiocommunications transmitter, register and spectrum licence (s 5 Note 1). It also references the Radiocommunications (Interpretation - Technical Framework) Determination 2024 or its successor for technical terms like AAS, average ground height, EIRP, Australian Spectrum Map Grid and HCIS identifier (s 5 Note 2). How those upstream instruments define these terms will influence the Determination’s operation.
• A specific interaction is flagged with subsection 145(1) of the Act: the Determination’s provisions feed into ACMA’s ability to refuse to include transmitter details in the Register where operation could cause unacceptable interference (s 7 Note). This is an explicit link between the Determination’s technical thresholds and an administrative power in the Act.

Interaction with prior Determination and transitional regimes

• The instrument repeals the 2015 Determination (s 4) and provides transitional treatment for transmitters already recorded in the Register prior to commencement (s 9). For such transmitters the benchmark for whether a level of interference is unacceptable is the 2015 Determination as it stood at the time the transmitter was included in the Register, unless the registered details change in a way described in s 9(3). That creates a continuity bridge but also potential complexity when assessing post‑commencement changes.

Interaction with international technical standards

• The Determination mandates use of specific ITU‑R Recommendations , P.525-4, P.526-15 and P.2108-0 , for propagation loss calculations (Schedule 1, item 3). By doing so it ties domestic legal effect to internationally recognised technical procedures. This is an interaction between domestic administrative regulation and international technical standards, and it makes the ACMA’s technical determinations reliant on those external documents for modelling and parameter values.

Spatial and mapping instruments

• The instrument depends on the Australian Spectrum Map Grid and HCIS identifiers to define urban areas and earth station protection zones (s 5 Note 2; Schedules 2 and 3). The precise boundaries and definitions in the Mapping instruments underpin several exceptions in s 7(2)-(5). Any changes to the spectrum map grid or HCIS identifier definitions in other instruments will therefore change how these exceptions operate, in accordance with s 6 which states references to other legislative instruments are to be read as in force from time to time.

Licence conditions and the Register regime

• The Determination interacts with licence core conditions by treating contraventions of core conditions relating to maximum permitted radio emission outside authorised spectrum or geographic area as unacceptable per s 7(1)(a). That creates a two‑way interaction: licence core conditions will shape what is unacceptable under the Determination, and the Determination’s device boundary rules inform whether core conditions have been breached.
• The note to s 7 also points to subsection 69(2) of the Act which exempts some transmitters from registration under their 3.4 GHz spectrum licence; the Determination expressly recognises that exempt transmitters are not required to meet the device boundary criterion (s 7 Note). This is an interaction that narrows the Determination’s coverage based on other statutory exceptions.

Evidentiary and administrative review channels

• The Determination does not amend judicial review or merits review channels directly. However, by creating technical thresholds that feed into ACMA’s registration decisions and potentially into licence variation or enforcement decisions under the Act, it creates matters that could be the subject of administrative review, merits review or judicial review under the Acts governing ACMA’s decisions. The Determination itself does not specify those review mechanisms, but its effects operate through decisions made under the Act and other legislation referenced in s 6.

In sum, the Determination is not standalone. It is tightly integrated with the Radiocommunications Act, the Register regime, technical interpretation instruments, the Australian Spectrum Map Grid and HCIS mapping data, and with international ITU‑R standards. Any legal or technical changes in those instruments or standards will change how the Determination operates in practice.

This instrument expressly repeals the Radiocommunications (Unacceptable Levels of Interference - 3.4 GHz Band) Determination 2015 (s 4). The instrument itself commences on 23 September 2025 (s 2). Beyond the repeal and commencement dates specified, the instrument contains several built‑in mechanisms that mediate change over time.

Key points in the instrument’s amendment and continuity architecture:

• Repeal of 2015 Determination: Section 4 operates as an immediate repeal of the 2015 Determination when this instrument commences. That is the primary formal amendment effect.
• Transitional continuation for registered transmitters: Section 9 preserves the 2015 Determination as the operative benchmark for determining whether interference from a transmitter registered before commencement is unacceptable for the purposes of subsection 145(4) of the Act. That is a conditional continuity mechanism rather than a formal amendment to the 2015 Determination. It means that registered transmitters remain subject to the technical thresholds in force at the time of their registration unless they make certain registered changes (s 9(2)-(3)).
• Protection of smaller changes: Section 9(3) provides that if after commencement a registered detail changes and the newly recorded device boundary is equal to or less than the old boundary on each radial, then an interference level which but for this subsection would be unacceptable is not unacceptable because of that change. This is a lock‑in mechanism that prevents the new Determination from immediately turning benign changes into an unacceptable result for previously registered transmitters, subject to the inequality condition.
• References to instruments as they stand from time to time: Section 6 instructs that references to other legislative instruments are to be read as references to those instruments "as in force from time to time". This design means that future amendments to the Radiocommunications (Interpretation - Technical Framework) Determination 2024 or other instruments will dynamically feed into how this Determination applies.
• Reliance on external technical standards with edition references: The instrument specifies particular editions of ITU‑R recommendations (for example P.526-15). If future instruments or ACMA administrative practice adopt updated ITU‑R recommendations by reference (as allowed by s 6), the propagation loss calculations may change without this Determination being formally amended.

No other amendments, revocations or modifications are included in the text you provided. If the ACMA or the Government wishes to alter the substantive device boundary methodology, LOP values, the distance increments, or the urban/earth station zone lists, that would require a replacement or a later amending legislative instrument. The current instrument’s design provides for two forms of stability: a hard repeal of the 2015 Determination on commencement and a soft continuity for pre‑existing registered transmitters via s 9.

The instrument itself does not record any judicial or administrative decisions. It repeals the 2015 Determination and supplies a new technical framework; no cases, appeals or tribunal outcomes are mentioned in the text provided. Accordingly, there is no litigation history embedded in the instrument's text.

That absence has a few practical implications for practitioners and compliance officers:

• No precedential administrative interpretation: Because the Determination is new and the text does not cite any prior administrative decisions, there are no instrument‑specific administrative precedents to guide how ACMA will apply the device boundary method in borderline or contested factual contexts. Parties should therefore expect that initial disputes will be resolved through ACMA processes and potentially by merits or judicial review where the Act and other instruments provide such avenues.
• Predictable themes for future litigation: Based on the Determination’s technical and definitional content, anticipated sources of dispute that may lead to litigation or merits review include: whether a device boundary was calculated in strict accordance with Schedule 1; the adequacy of statistical methods used to satisfy the 95 percent confidence requirement in s 8; the measurement of antenna phase centre height and the 5 parts in 100 tolerance in Schedule 1, item 4; application of the LOP for AAS versus non‑AAS transmitters and whether the AAS assumption in Note 1 of item 2 is satisfied in practice; the interpretation and application of radial non‑crossing conditions and HCIS identifier mapping for s 7(2)-(5); and the interaction of s 9 transitional protections when registered details change.
• Burden of technical evidence: Future litigation is likely to be technical, with disputes turning on modelling inputs, path profiles, ground height estimation and whether the ITU‑R procedures and increments were properly applied. The Determination’s prescription of specific ITU‑R methods will concentrate dispute over whether those methods were applied correctly and whether parameter estimation met the 95 percent confidence requirement.
• Administrative review options under the Act: Although the Determination does not set out appeals or review rights, decisions by ACMA to refuse registration or to take action based on an "unacceptable" determination under s 7 will be decisions made under the Act and so will be amenable to the review and appeal pathways provided by the Act and by administrative law generally. Practitioners should expect that judicial review or merits review of ACMA decisions that apply this Determination will focus on both legal error and technical fact.

In short, there is no existing litigation history in the instrument. However, the Determination sets up technical thresholds that are likely to generate contestation in practice, and future litigation or review is plausibly expected to concentrate on modelling fidelity, measurement tolerances and mapping of HCIS identifiers.

This Determination contains a number of technical and procedural traps for the unwary. Below are specific points that practitioners, licence holders and technical advisers should watch for, each grounded in the instrument's text.

1. The start point of radial increments and the maximum radius

• Device boundary checks begin at m = 2, i.e. 2 × 100 m = 200 m, not zero or 100 m (Schedule 1, item 1). Many intuitive calculations might start at the antenna or at 1 × 100 m. The instrument’s choice means the first evaluated point is 200 m from the transmitter on each radial.
• The device boundary has a hard cap at m = 1010, i.e. 101,000 m per radial (Schedule 1, item 1(1)-(2)). If the criterion never becomes ≤ 0 before that cap, the end point is at 101,000 m.

2. Device boundary cannot be calculated is itself an "unacceptable" trigger

• If the device boundary "cannot be calculated in accordance with item 1 of Schedule 1" the interference is unacceptable (s 7(1)(c)). That creates an immediate compliance risk for operators who cannot produce the specified technical analyses, either for lack of data or modelling expertise.

3. AAS is treated differently, but tied to an operational assumption

• For transmitters with AAS, RP is defined as the sum of certain antenna gains and total radiated power, with an LOP that is 8 dB higher (less protective) than for non‑AAS transmitters (LOP −90 dBm/MHz versus −98 dBm/MHz) (Schedule 1, item 2). Note 1 explicitly states the allowance is based on the assumption that beam pointing angles and/or power can be dynamically controlled to ensure RP is not exceeded. In practice this requires logging, control systems and demonstrable limits; otherwise the AAS operator may not safely rely on the higher LOP.

4. Strict propagation model prescriptions and the 100 metre profile increment

• The instrument prescribes specific sections of ITU‑R recommendations and a 100 metre increment path profile development (Schedule 1, item 3). Deviation from those models is not authorised by the instrument and may render calculations non‑compliant.

5. The 95 percent confidence requirement is one‑sided and conservative

• Section 8 mandates estimation with at least 95 percent confidence that the true parameter value will always remain below the requirement. Practically, this is a conservative, one‑sided statistical standard that imposes an evidentiary burden to demonstrate that modelling errs on the side of not understating interference risk.

6. Antenna height measurement tolerance and reference point

• Antenna height is defined relative to the lowest elevation point where the supporting structure meets the ground or sea, measured with error less than 5 parts in 100 (Schedule 1, item 4). Small changes in the reference point can materially alter propagation loss in some terrain, so measurement and documentation must follow the specified rule precisely.

7. Group calculation can magnify limits

• For groups of transmitters RP is equalised to the maximum horizontally radiated power of any transmitter in the group (Schedule 1, item 1(2)). This means a single high‑power transmitter in a group can effectively enlarge device boundary constraints for the entire grouped calculation.

8. The exceptions to geographic requirement are narrow and conditional

• The exceptions in s 7(2)-(5) require the out‑of‑area part to be connected to a radial "mentioned in item 1 of Schedule 1" and for that radial not to cross the geographic area of another 3.4 GHz licence. They also rely on HCIS identifiers and the Australian Spectrum Map Grid. Misclassification of HCIS cells or incorrect mapping can easily invalidate an intended exception.
• Particular geographic exclusions in s 7(4)(b)(iii) list HCIS identifiers (IW3E, IW3I, IW3M, IW6A, IW6E, KX9, LX7, LX8, LX9). These are specific and must be checked.

9. Urban area exception limited to 3400-3475 MHz

• Section 7(5) provides an exception for parts of the device boundary that lie inside an urban area only where the transmitter has occupied bandwidth contained in 3400-3475 MHz. Transmitters operating above 3475 MHz do not get the urban area exception.

10. Transmitters on aircraft are always unacceptable

• Section 7(1)(d) makes any transmitter on an aircraft an automatic unacceptable source if operated under a 3.4 GHz spectrum licence. Mobility and airborne operation thus create a categorical compliance exclusion.

11. Transitional protections can be lost by changes to registered details

• The protective rule in s 9(3) applies only if the new device boundary distances are equal to or less than the old distances on each radial. Any change that increases the device boundary on one or more radials can cause the transmitter immediately to be treated under the new Determination.

12. Multiple external dependencies

• The Determination depends on other instruments and mapping datasets (Australian Spectrum Map Grid, HCIS identifiers, Radiocommunications (Interpretation - Technical Framework) Determination 2024). Changes to these upstream instruments will affect outcomes by reference (s 6). Practitioners must track all these linked instruments.

Each of these points translates into concrete operational steps and documentary evidence requirements. Failure to appreciate these details risks administrative findings of "unacceptable interference" with attendant registration consequences under the Act.

Compliance under this Determination is technical and documentation heavy. Below is a practical compliance checklist and procedural steps, tied to the instrument’s provisions, for licence holders, operators and technical advisers.

1. Establish whether the Determination applies to your transmitter

• Confirm the transmitter operates under a 3.4 GHz spectrum licence and that its operation falls within the 3400-3800 MHz band as defined (s 5). If the transmitter is exempt from registration under subsection 69(2) of the Act, note that the device boundary criterion does not apply to that transmitter (s 7 Note).

2. Prepare to calculate the device boundary per Schedule 1

• Use radials at each integer degree from 0 to 359 and evaluate the device boundary criterion at m × 100 metre increments for m = 2 to 1010 (Schedule 1, item 1). Ensure your process starts at 200 m and extends to 101,000 m if necessary.
• For each radial, compute RP and MP at each increment and find the first increment where RP - MP ≤ 0; that point is the end point and constitutes the device boundary for that radial (Schedule 1, item 1(2)).

3. Determine RP robustly

• Calculate RP as the horizontally radiated power in dBm EIRP per MHz for each bearing σn (Schedule 1, item 2). For transmitters with AAS, follow the instrument’s RP definition in Note 1 of item 2, summing antenna gains in the horizontal plane and the azimuth direction plus the total radiated power (Schedule 1, item 2 Note 1).
• For groups of transmitters, set RP equal for each bearing and equal to the maximum horizontally radiated power of any group member (Schedule 1, item 1(2)).

4. Compute MP accurately

• MP = PL + LOP - Gr (Schedule 1, item 2). Use Gr = 0 dBi including feeder loss. Use the correct LOP: −90 dBm/MHz for AAS transmitters and −98 dBm/MHz for other transmitters (Schedule 1, item 2).

5. Use the specified propagation loss procedures and profile rules

• For antenna heights > 6 m above ground, use ITU‑R P.525-4 section 2.2 and P.526-15 section 4.5.2 (Schedule 1, item 3(1)(a)).
• For antenna heights ≤ 6 m above ground, use P.525-4 section 2.2, P.526-15 section 4.5.2 and P.2108-0 section 3.2 (Schedule 1, item 3(1)(b)).
• Develop the path profile at 100 m increments and work out average ground height at each increment (Schedule 1, item 3(3)). Use the receiver nominal height of 5 m AGL for P.526-15 (Schedule 1, item 3(2)(a)).
• For P.2108-0 corrections apply the 0.08% location percentage, cap the correction between 0 and 8 dB and apply it at one end only as directed (Schedule 1, item 3(4)).

6. Meet the 95 percent confidence requirement

• Unless otherwise specified, estimate parameters so that with at least 95 percent statistical confidence the true value will always remain below the requirement specified in this instrument (s 8). Practically this requires statistical modelling, uncertainty quantification and conservative parameter selection or testing regimes. Maintain documentation of the statistical methods, assumptions and data.

7. Measure antenna height to the specified tolerance

• Determine the antenna phase centre height relative to the lowest elevation point of the supporting structure’s intersection with the ground or sea, and ensure measurement error is less than 5 parts in 100 (Schedule 1, item 4(1)). For a group use the maximum height among members (Schedule 1, item 4(2)). Document survey methods, reference points and measurement error analyses.

8. Map and check exceptions carefully

• If parts of your device boundary lie outside the licence geographic area, test whether s 7(2)-(5) exceptions apply. This requires: (a) determining whether the out‑of‑area part lies outside the Australian Spectrum Map Grid (s 7(2)(a)); (b) checking whether the out‑of‑area part lies within a listed earth station protection zone (s 7(3) and Schedule 2); (c) determining whether the out‑of‑area part lies inside an urban area listed in Schedule 3 and whether the transmitter’s occupied bandwidth is contained in 3400-3475 MHz (s 7(5)); and (d) verifying that the connecting radial is "mentioned in item 1 of Schedule 1" and does not cross the geographic area of another 3.4 GHz spectrum licence (s 7(2)-(5)). Use the HCIS identifiers in Schedules 2 and 3 for spatial mapping; keep records of mapping procedures and coordinate system transformations.

9. Avoid airborne operation under the licence

• Do not operate the transmitter on an aircraft under a 3.4 GHz spectrum licence if you wish to avoid the Determination’s "unacceptable" classification (s 7(1)(d)).

10. Document Register entries and plan changes

• For transmitters already included in the Register before commencement, rely on s 9 transitional protection; however, if you intend to change registered details, calculate the new device boundary and ensure distances on each radial are equal to or less than the old device boundary if you want to retain the transitional non‑unacceptable outcome (s 9(3)). Keep pre‑ and post‑change device boundary records and technical justification.

11. Prepare for ACMA verification and possible administrative action

• Maintain modelling inputs, path profiles at 100 m increments, propagation loss calculations, antenna height surveys, AAS control logs (if relevant), and statistical evidence for parameter confidence. These will be the core documents ACMA will examine if it is assessing whether a transmitter causes unacceptable interference under the Determination. Be prepared to show evidence that device boundary calculations were made strictly in accordance with Schedule 1 and s 8.

12. Engage technical advisers familiar with ITU‑R methods and HCIS/Australian Spectrum Map Grid

• The Determination’s mandatory reference to ITU‑R methods and HCIS identifiers means that technical advisers must be competent in these models and mapping systems. Ensure that consultants can certify adherence to the specific sections cited and can demonstrate that parameter estimation meets the 95 percent confidence requirement.

Following this checklist converts the Determination’s prescribed technical rules into a practical compliance programme: precise measurement, specific modelling methods, conservative statistical estimation, careful mapping against HCIS identifiers and careful handling of Register changes under s 9.