Radiocommunications (Unacceptable Levels of Interference – 2.5 GHz Band) Determination 2023

The instrument’s core technical concepts are device boundary, device boundary criterion (RP - MP), horizontally radiated power (RP), mean protection level (MP), effective antenna height, DEM-3S-based terrain averaging, AAS treatment, and rigorous geodesic positioning. The definitions in section 5 and the Schedules define these precisely.

Device boundary: For each fixed transmitter (or group treated as one transmitter), the device boundary is the polygon formed by a set of radial end points, one per degree (n = 0 to 359). Along each radial the instrument evaluates up to 400 increments of m×100 metres; the end point is the first increment where the device boundary criterion RP - MP ≤ 0, or the 400th increment otherwise (Schedule 2, item 1). The device boundary therefore depends on power, antenna gain pattern, propagation loss, nominal receiver gain, and the LOP.

Device boundary criterion, RP - MP: RP is horizontally radiated power in dBm EIRP per 30 kHz for each bearing σn. The instrument specifies how RP is calculated for conventional systems and for AAS (Schedule 2, item 2). MP equals PL(lmn, Lmn) + LOP − Gr where PL is the propagation loss calculated via the propagation-loss model (Schedule 2, item 2). LOP is a fixed level-of-protection: −108 dBm/30 kHz for systems that incorporate an AAS, −116 dBm/30 kHz otherwise (Schedule 2, item 2).

Horizontally radiated power (RP): RP is defined in the Schedule 2 table (item 2). It sums the true mean power at the antenna connector within the licence band and the antenna gain relative to an isotropic antenna in a specified horizontal-plane direction containing the antenna phase centre (section 5 definition). For AAS, Note 1 to Schedule 2 defines RP as antenna gain towards the horizontal plane and azimuth σn plus total radiated power in dBm, and explicitly states that this assumes dynamic control of beams and/or power to ensure RP is not exceeded.

Propagation-loss model: Schedule 2 item 3 prescribes calculation of PL(lmn, Lmn) using effective antenna height (Schedule 3) and Vincenty’s direct formulae (Schedule 3, item 3) to determine geodesic coordinates for each increment; Schedule 3 further details the average ground height calculation using DEM-3S (3-second SRTM derived DEM) aggregated by a 3 × 3 cell matrix at the DEM resolution. There are special rules for cells at particular grid alignments (modulus conditions) and for groups of transmitters (use the highest hgt in the group).

AAS distinction: The instrument treats Active Antenna Systems differently in two ways: a higher LOP (less stringent protection number, −108 dBm vs −116 dBm), and an RP definition that accounts for dynamic beamforming under the assumption the system can control beam pointing and power to keep RP below limits (Schedule 2, item 2 Note 1). The instrument thus embeds an engineering assumption about AAS controllability.

Geodetic and measurement precision: Location must be given in latitude/longitude referenced to GDA94 and measured with error under 10 metres (Schedule 1). For hgt the permitted measurement error is less than 5 parts in 100 (Schedule 3, item 1). Schedule 3 requires use of Vincenty’s formulae (GRS80 parameters) for positional calculations.

Unacceptable-interference triggers: Section 10 sets multiple independent triggers: contravention of core licence conditions regarding emissions outside authorised spectrum or geographic area; any part of the device boundary outside the licence geographic area (with a narrow exception for radials that do not cross land outside the geographic area permanently above the territorial sea baseline); emissions above the horizontal plane greater than 45 dBm/30 kHz EIRP; and operation in the lower 2.5 GHz band with effective antenna height above 10 metres. Section 12 covers transitional application for transmitters registered before commencement.

Accuracy/confidence requirement: Section 11 requires that, unless otherwise specified, parameter values in Schedules 2 and 3 be estimated with at least 95% confidence that the true value will remain below required limits. This invokes statistical confidence in modelling and measurement outputs.

Interaction with Register and other Act provisions: The instrument operates in the Register context. Notes reference section 144 (information to be included in the Register) and section 145(1) (ACMA may refuse to include transmitter details in the Register if operation could cause unacceptable interference). Section 6 states references to other instruments are to be read as in force from time to time.

Collectively, these concepts produce a deterministic, terrain-aware method to map where a transmitter’s calculated signal will meet the protection threshold (MP) and thereby define the boundary of authorised operation for interference assessment.

The instrument affects spectrum licence holders and authorised third parties operating radiocommunications transmitters in the 2.5 GHz band (section 5 definitions of “2.5 GHz spectrum licence” and repeated references throughout). It also affects other radiocommunications licence holders and receivers in and adjacent to the 2.5 GHz band by defining the protection levels and device boundary that govern registration and interference findings (section 10 and Schedule 2).

More specifically, affected parties include:

• Operators of fixed transmitters and fixed receivers (section 5 definitions of fixed transmitter and fixed receiver): the instrument’s device boundary and effective antenna height rules apply to devices “located at a fixed point on land or sea” and “not designed or intended for use while in motion” (section 5).
• Owners/operators of Active Antenna Systems (AAS): the instrument contains bespoke provisions for AAS in Schedule 2 (different LOP, explicit calculation of RP for AAS, assumption of dynamic beam/power control), so AAS operators must document and model dynamic performance to show RP compliance.
• Groups of transmitters and groups of receivers: spectrum licensees that operate clusters of identical transmitters or receivers on the same structure may choose or be required to treat them as a single group under section 8 (group of radiocommunications transmitters) and section 9 (group of radiocommunications receivers). The grouping rules require same centre frequency, emission designator, same antenna model and co-location within 20 metres of each antenna phase centre, and identical ACMA antenna identification numbers (sections 8(1)(a)-(e) and 9(1)(a)-(d)). A transmitter cannot belong to more than one group (sections 8(2), 9(2)).
• Parties preparing Register entries or amendments: section 12 provides a transitional regime for transmitters included in the Register before commencement. Where Register details change and the new device boundary is on each radial equal to or less than the old device boundary, the change will not make interference unacceptable if it would otherwise be (section 12(3)). Thus those seeking to change registered details must compute device boundaries before and after changes to rely on transitional protection.
• Equipment vendors and testing/calculation service providers: the instrument’s technical prescription,100-metre radial increments, up to 400 increments, DEM-3S terrain height averaging, Vincenty formulas, 95% confidence estimation requirements,imposes modelling and measurement tasks that vendors and consultants will perform for licensees to demonstrate compliance.

Who pays: the instrument’s burdens fall to spectrum licensees and their authorised third parties. They must supply accurate site coordinates (measured to <10 m error), antenna heights (hgt measured to <5% error), RP values, and terrain inputs (DEM-3S). Costs include modelling, measurement, potentially lower antenna mounts or reduced power, and Register administration. The ACMA decides whether to record a transmitter on the Register and may refuse registration where operation could cause an unacceptable level of interference (note to section 10 referring to subsection 145(1) of the Act).

Geographic constraints: the device boundary must lie within the geographic area of the licence, subject to the limited exception in section 10(2). The exception concerns portions of the device boundary connected to a radial that does not cross land outside the licence area that is permanently above the Australian territorial sea baseline. The presence of this exception means coastal deployments and areas over sea/territorial waters interact with the geographic-area test, thereby affecting coastal network planning and border cases.

In short, the instrument affects technical operators, spectrum licence holders, their contractors, and other radio users whose protection depends on the device boundary and the LOPs set here.

Duties under the instrument fall primarily on 2.5 GHz spectrum licensees and authorised third parties who operate transmitters. Rights are largely procedural and protective, tied to registration status and transitional protections.

Duties (what operators must do):

• Compute and record accurate transmitter location and device boundary: the location must be provided in latitude/longitude referenced to GDA94 and measured with error less than 10 metres (Schedule 1). The device boundary must be calculated per Schedule 2 item 1, evaluating the RP - MP criterion at m×100 metre increments along n-degree radials (Schedule 2 item 1).
• Use specified datasets and formulas: operators must use DEM-3S (as cited in section 5 definitions) for terrain height and apply Schedule 3 procedures to compute effective antenna height and average ground height (Schedule 3, items 1 and 2). The geodesic calculations must be implemented using Vincenty’s Direct Formulae as specified (Schedule 3, item 3).
• Apply the RP - MP device boundary criterion: calculate RP in dBm EIRP per 30 kHz for each bearing, determine PL(lmn, Lmn) via the propagation-loss steps, apply LOP and Gr as given, and find the radial end point where RP - MP ≤ 0 (Schedule 2 items 2 and 3).
• Meet measurement and modelling accuracy/confidence requirements: parameter values in Schedules 2 and 3 are to be estimated with at least 95% confidence that the true value will remain below the requirement (section 11). Antenna height measurement error must be less than 5 parts in 100 (Schedule 3 item 1(1)(a)).
• Observe bright-line operational limits: do not operate with emissions above the horizontal plane greater than 45 dBm/30 kHz EIRP (section 10(3)); do not operate in the lower 2.5 GHz band with effective antenna height greater than 10 metres (section 10(4)). Ensure operation does not cause contravention of a licence core condition regarding emissions outside authorised spectrum or geographic area (section 10(1)(a)).

Rights and procedural features for operators:

• Transitional protection for previously-registered transmitters: where a transmitter was included in the Register before commencement, the instrument applies the 2012 Determination to that transmitter unless a change is recorded that increases the device boundary on any radial (section 12(2)-(3)). In effect, an operator who does not increase device boundary distances is insulated from the new Determination making interference unacceptable immediately after a change is recorded (section 12(3)).
• Grouping nomination: where a transmitter could belong to more than one group, the spectrum licensee or authorised third party may nominate one group for the transmitter (notes to sections 8(2) and 9(2)). This is a procedural right to avoid overlapping group assignments.
• Use of AAS rules: AAS operators have a different LOP and an explicit RP formula which allows representation of beamforming gains in the horizontal plane, subject to the instrument’s assumption that dynamic control will ensure RP is not exceeded (Schedule 2, item 2 Note 1).

Enforcement-related duties:

• Register accuracy and timely notification of changes: because the ACMA’s refusal powers under s145 of the Act relate to whether operation could cause unacceptable interference, licensees must ensure Register details remain accurate and that any planned change is reflected with computed device boundaries consistent with the instrument (notes to sections 8, 9 and section 12).
• Measurement protocols consistent with “good engineering practice” when measuring power and bandwidth: section 5’s definition of “maximum true mean power” refers to measurement via adjacent channel power meters or spectrum analysers and states that estimation of measuring equipment accuracy and measurement protocol should be in accordance with good engineering practice (section 5 definition note).

Decision-makers and their responsibilities:

• ACMA: responsible for including transmitter details in the Register and for deciding, under s145(4) of the Act (the instrument’s authority per section 3), whether operation could cause unacceptable interference using this Determination. The instrument does not allocate new enforcement powers beyond the Act but supplies the technical test the ACMA is to apply.

In sum, operators must implement technically prescriptive modelling, measurement and record-keeping steps; they have limited procedural protections if they maintain or reduce device boundaries compared with earlier registration; and the ACMA has the decision rights under the Act, with this Determination supplying the calculus.

The Determination itself does not create criminal offences or civil penalty provisions; it prescribes technical criteria the ACMA will use to assess whether operation of a transmitter could cause an “unacceptable level of interference” for the purposes of subsection 145(4) of the Radiocommunications Act 1992 (sections 3 and 10). Enforcement consequences therefore derive from the Act (as noted in the instrument), not from the Determination’s text.

Key enforcement mechanisms and consequences identified in or implied by the instrument and its notes:

• Register inclusion/refusal: The instrument is expressly made under subsection 145(4) of the Act (section 3). The instrument’s note to section 10 quotes subsection 145(1) of the Act: the ACMA may refuse to include details of a radiocommunications transmitter in the Register if the ACMA is satisfied that operation of the transmitter could cause an unacceptable level of interference. The Register is the statutory mechanism through which transmission operation under a spectrum licence is made known to the regulator and third parties (see the notes to sections 8 and 9 referencing section 144 of the Act for Register information requirements). Refusal to include transmitter details in the Register under the Act has practical enforcement effect because registered device details are necessary for authorised operation under a spectrum licence and for the ACMA’s control of spectrum use.
• Licence core condition contraventions: Section 10(1)(a) treats as unacceptable any interference where operation results in contravention of a core condition of the licence relating to the maximum permitted level of radio emission outside authorised spectrum parts or geographic area. Contravention of core conditions of spectrum licences can attract enforcement under the Act, including notices, directions, or other remedies available to the ACMA (the Determination does not restate those remedies).
• Technical prohibitions with immediate operational effect: Section 10(3) and (4) create bright-line technical triggers,emissions above the horizontal plane greater than 45 dBm/30 kHz EIRP, and operation in the 2.5 GHz lower band with effective antenna height greater than 10 metres. If operation would meet these triggers, the Determination treats that level of interference as unacceptable. ACMA would apply that finding under the Act to refuse Register inclusion or take other action authorised by the Act.
• Transitional effect on enforcement: Section 12 provides a transition for transmitters registered under the 2012 Determination: until a relevant change is recorded that increases device boundary distances, the prior determination’s standards continue to govern whether interference is unacceptable. This restricts immediate application of the 2023 criteria to pre-existing registered transmitters unless they change details and thereby lose the transitional protection in section 12(3).

What the instrument does not supply:

• The instrument does not set out civil penalty or criminal sanction provisions itself. It relies on the Act’s regulatory framework for enforcement. Readers must consult the Act for the specific enforcement powers, penalty regimes, and administrative processes available to the ACMA.
• There is no procedural detail in the Determination on how the ACMA will audit, test, or verify modelling outputs, nor does it provide a compliance timetable or grace period for unregistered but operating transmitters other than the transitional rule in section 12.

Implementation and evidentiary implications:

• The Determination imposes technically precise computation and measurement requirements (DEM-3S, Vincenty formulae, 95% confidence estimates). In enforcement contexts, the ACMA can compare declared device boundaries and associated calculations against the Determination’s procedures. That implies an evidentiary need for licensees to retain modelling inputs, measurement data, and documentation demonstrating compliance with the Accuracy rule (section 11), the location/hgt measurement tolerances (Schedule 1 and Schedule 3), and DEM-3S processing steps (Schedule 3).
• The AAS assumption (Schedule 2 Note 1) that beam pointing and power can be controlled dynamically to ensure RP is not exceeded creates a compliance boundary: if an AAS operator claims the AAS meets RP limits through dynamic control, the ACMA could require method documentation or measurement evidence consistent with the Determination.

In short, the Determination supplies the technical yardstick ACMA will use within its statutory enforcement toolbox under the Act. The instrument itself leaves the actual sanctions and administrative processes to the Act and to ACMA practice.

The Determination is a legislative instrument made under subsection 145(4) of the Radiocommunications Act 1992 (section 3). Its legal effect is to establish the technical test the ACMA applies in relation to subsection 145(4) , whether it is satisfied that operation of a transmitter could cause an unacceptable level of interference. Interaction with other laws and instruments appears in multiple places in the Determination.

Primary interactions with the Act:

• Register and ACMA powers: The Determination is tied into the Act’s Register framework. Notes to sections 8, 9 and 10 refer to section 144 (information that must be included in the Register) and subsection 145(1) (the ACMA may refuse to include details where operation could cause unacceptable interference). Thus the Determination operates as the technical standard the ACMA applies when exercising statutory powers under the Act.
• Exemptions under the Act: The note to section 10 acknowledges subsection 69(2) of the Act, which exempts some transmitters from the requirement to be registered in the Register under their 2.5 GHz spectrum licence. That means the Determination’s practical effect depends in part on registration obligations and exemptions under the Act.

Cross-references to other legislative instruments and documents:

• The Determination requires application of the International Telecommunication Union’s Radio Regulations when determining emission designators (section 7). It explicitly notes the Radio Regulations are not regulations made under the Act (section 5 note), and that Appendix 1 of the Radio Regulations sets out the method for emission designation (section 7 note). The Radio Regulations are therefore an external technical standard referenced by the Determination.
• Section 6 adopts a conventional statutory cross-reference rule: references to other legislative instruments are to be read as in force from time to time, and references to other writings are to be read as in force or existence from time to time (section 6(a)-(b)). It explicitly points readers to the Acts Interpretation Act 1901 for Commonwealth Acts references and to section 314A of the Act.

Interaction with geodetic and terrain data regimes:

• The Determination mandates use of the DEM-3S dataset (section 5 definition and Schedules). DEM-3S is a dataset published by Geoscience Australia; the Determination requires its use to compute average ground heights and thus effective antenna heights and propagation loss (Schedule 3 item 2). This embeds an interaction with the Commonwealth’s geospatial data outputs and the standards used by Geoscience Australia.
• Geodetic datum: location and coordinates are required to be referenced to GDA94 (section 5). Schedule 3 states Vincenty’s Direct Formulae are to use GRS80 parameters as referenced by GDA94. This ties the Determination to specific geodetic standards used in Commonwealth mapping and cadastral systems.

Regulatory overlap and boundary areas:

• Territorial sea baseline reference: section 10(2) excludes certain parts of device boundary from being unacceptable where the radial “does not cross over land outside the geographic area of the licence that is permanently above the Australian territorial sea baseline.” This creates an interaction with maritime law definitions found in the Seas and Submerged Lands Act 1973 (section 5 definition of Australian territorial sea baseline references section 7 of that Act). Coastal deployments and operations over sea therefore interact with maritime boundary definitions when applying the device boundary geographic-area test.
• References to the ACMA Register and the need to include antenna identification numbers (sections 8(1)(e), 9(1)(d) and note references to section 144 of the Act) mean the Determination operates alongside ACMA’s Register rules and any instruments made under section 144 guidance.

What the Determination does not change:

• It does not alter licence conditions themselves , it provides the test the ACMA applies to decide if inclusion in the Register is appropriate and whether operation would cause unacceptable interference. Enforcement and sanctions remain governed by the Act and any subsidiary regulatory instruments made under it.
• It does not modify the Radio Regulations themselves; it instructs how to use the Radio Regulations for emission designators (section 7), but the international instrument remains external.

Practical consequence of these interactions:

• Parties must apply the Determination in the context of the Act’s registration and enforcement regime, use the specified geodetic and terrain datasets and methods (GDA94, DEM-3S, Vincenty), and be aware that maritime/territorial sea definitions influence geographic-area assessments. The Determination’s references to other instruments mean that changes to those external instruments (for example, updates to DEM-3S or to the Radio Regulations) may affect practical application unless specifically otherwise provided.

This Determination expressly repeals the Radiocommunications (Unacceptable Levels of Interference - 2.5 GHz Band) Determination 2012 (see section 4). The 2012 instrument is therefore replaced for transmitters included in the Register after commencement, subject to the transitional protections in section 12 for transmitters included in the Register prior to commencement.

Key points drawn from the instrument concerning amendment and transitional arrangements:

• Repeal: section 4 makes a straight repeal of the 2012 Determination [F2012L02545]. The operative text of the 2012 Determination therefore no longer applies to new registration actions after this instrument commences, unless transitional rules preserve its application for certain registered transmitters (section 12).
• Commencement timing: section 2 states the instrument commences at the start of the day after the day it is registered on the Federal Register of Legislation. The Determination itself does not record the date of registration; the Register entry will therefore determine the precise commencement date.
• Transitional protection for existing registered transmitters: section 12(2) provides that for radiocommunications transmitters that were included in the Register before commencement (relevant transmitters), the level of interference is unacceptable only if it would have been unacceptable under the 2012 Determination as in force at the time the transmitter was included in the Register. This preserves the earlier standard for pre-existing registered transmitters.
• Change-induced re-evaluation: section 12(3) creates a conditional rule where, if a relevant change to a registered transmitter’s detail is recorded after commencement, and the new device boundary is on each of the radials equal to or less than the old device boundary, then even if the new details would otherwise cause the transmitter to be unacceptable under the new Determination immediately after the change, that level of interference is not unacceptable because of the change. This provides a degree of protection for changes that do not expand device boundary distances.
• Definitions relevant to transitions: section 12(4) defines change time, new device boundary, old device boundary and registration time for the transitional rule.

What is not in the instrument’s amendment history:

• The Determination does not record any previous amendments between 2012 and 2023; it simply repeals the 2012 instrument. No other prior versions or amendments are mentioned in the text supplied.
• There are no amendments to the Act recorded in this instrument; it is a legislative instrument under the Act.

Practical implications for amendment treatment:

• Operators with transmitters registered under the 2012 Determination should compare pre-commencement device boundaries and the post-change device boundary calculations, because the transitional rule operates on a per-radial comparison. If any radial’s device boundary increases compared with the old device boundary, transitional protection may be lost for that transmitter after a change is recorded.
• The repeal and replacement approach means that the ACMA has updated its technical standard. Licence holders and third parties must check whether their registered transmitters remain compliant under the new computational method when they make changes or when registering new transmitters.

The instrument’s repeal-and-replace amendment history is therefore straightforward: 2012 Determination repealed; 2023 Determination in force from registration date; transitional rules preserve earlier standards for pre-existing registered transmitters except where changes increase device boundary distances.

The Determination text supplied contains no litigation history. It does not cite any cases or judicial decisions, and it does not record any litigation relating to the 2012 Determination or its application. The instrument references statutory provisions of the Act and external technical documents (DEM-3S, Radio Regulations), but no court or tribunal decisions are mentioned.

Implications for practitioners:

• There is no precedent or case law in the Determination text to guide interpretation of its technical terms or transitional protections. That means the primary sources for interpretation are the Determination’s text, the Act (particularly sections 144 and 145, which are referenced in notes), and any ACMA policy or administrative guidance that may accompany the Determination (not supplied in this instrument).
• Where disputes arise over how the device boundary calculations are to be carried out, or whether a transmitter’s operation causes unacceptable interference under section 10, the Determination provides detailed technical steps. Disputes will most likely turn on (1) whether an operator applied the specified DEM-3S, Vincenty and propagation-loss calculations correctly; (2) whether measurement and modelling met the Accuracy requirement in section 11; and (3) how AAS dynamic behaviour is represented relative to the assumption in Schedule 2 Note 1. Absent litigation history in the instrument, parties will need to rely on the text and, if necessary, test its interpretation before an administrative tribunal or court under existing Act-based appeal paths.
• Practitioners should check ACMA’s publications and regulatory guidance (outside this Determination) for any interpretative materials, and review the Act for appeal avenues. The Determination itself makes no comment about dispute resolution or adjudicative pathways.

In summary, the instrument contains no litigation history. Any legal challenges or interpretive disputes will need to be addressed through the Act’s mechanisms and, if litigated, will create new jurisprudence not reflected in the 2023 Determination text.

The Determination’s technical precision produces several operationally significant edge cases and compliance traps that practitioners and operators should note. The instrument’s own text contains many of these nuances.

1. Lower band effective-antenna-height limit (section 10(4)): Operation in the 2.5 GHz lower band (2500-2570 MHz) with effective antenna height greater than 10 metres is deemed to cause unacceptable interference. The effective antenna height is calculated via Schedule 3 with particular DEM-3S averaging rules. A seemingly small increase in mast height or the choice of DEM cell averaging can move a transmitter from acceptable to unacceptable.

2. 45 dBm/30 kHz EIRP above horizontal plane (section 10(3)): The Determination treats any emissions above the horizontal plane exceeding 45 dBm/30 kHz EIRP as unacceptable interference. For systems with elevation radiation (e.g. tall towers, downtilting antennas), careful measurement and control of power and antenna patterns are necessary to avoid this bright-line threshold.

3. Device boundary calculation granularity (Schedule 2 item 1): The device boundary uses 1-degree radials and 100-metre increments up to 400 increments. This discrete grid can produce small but material differences in calculated device boundaries depending on implementation precision, how the first increment where RP - MP ≤ 0 is identified (edge interpolation is not specified), and rounding/conversion of coordinates. Implementations must apply the prescribed Vincenty formulae (Schedule 3) and the DEM-3S cell selection rules precisely.

4. DEM-3S cell edge rule and modulus condition (Schedule 3 items 1(3) and 2(2)): Special handling applies where the seconds component of latitude or longitude plus 1.5 has a modulus of zero when divided by 3; then hs is sum of hgt and maximum height of adjacent DEM-3S cells, or the DEM cell to use is the adjacent cell with minimum height. These grid-alignment rules can change average-ground-height outputs for sites on certain coordinate grids, producing sudden changes in effective antenna height and device boundary outcomes.

5. AAS assumptions (Schedule 2 item 2 Note 1): For Active Antenna Systems the Determination defines RP on the basis that beam pointing angles and/or power can be controlled dynamically to ensure RP is not exceeded. That is an engineering assumption; an AAS operator claiming compliance on that basis must be able to evidence control logic and worst-case beam/power states. The Determination does not detail what evidence suffices.

6. Accuracy/confidence requirement (section 11): Parameter values in Schedules 2 and 3 must be estimated with not less than 95% confidence that the true value will always remain below the requirement. This imposes a statistical modelling burden. The Determination does not prescribe a statistical method or sampling plan; operators must adopt modelling practices that can substantiate 95% confidence levels in measurements and predictions.

7. Grouping constraints (sections 8 and 9): The rules for grouping transmitters/receivers require identical emission designator, centre frequency and antenna make/model, co-location within 20 metres and identical ACMA antenna identification numbers. Small differences in antenna model or placement can prevent grouping and change RP and device boundary calculations substantially for multi-antenna sites.

8. Lower frequency endpoints excluded per section 5(2): The instrument specifies that a reference to a part of the spectrum or frequency band includes all frequencies greater than but not including the lower frequency. This means the lower bound (e.g. 2500 MHz) is excluded. Edge-case emissions centred exactly at the lower boundary require careful interpretation to determine whether they fall within the band as applied.

9. Transitional protection is limited and per-radial (section 12): The transitional rule preserves the 2012 standard for previously registered transmitters unless a change increases device boundary distances on any radial. The per-radial comparison means small changes that extend the device boundary on even a single radial can expose the transmitter to the new Determination immediately.

10. No explicit verification or audit process set out: The Determination specifies calculation and measurement methods but does not set out ACMA’s verification process, collection of evidence, or timelines for audit. Operators should assume the ACMA may request underlying data and models to check compliance.

11. Maritime / territorial sea baseline nuance (section 10(2)): The exception to device boundary being outside geographic area triggers a test involving whether a radial “does not cross over land outside the geographic area of the licence that is permanently above the Australian territorial sea baseline”. That language is spatially and legally technical , coastal licensees should check maritime baseline definitions under the Seas and Submerged Lands Act 1973 and confirm whether radials are considered to cross land outside the geographic area.

12. External dependencies: Use of the Radio Regulations for emission designators (section 7) and reliance on DEM-3S (section 5 definitions) means changes to those external documents or their availability can affect compliance. Operators must ensure they use the versions and persistent identifiers specified.

Each of these points is grounded in the Determination text. The combination of discrete computational rules, precise geodetic and DEM processing, and bright-line operational thresholds means operators must execute calculations and measurements to the instrument’s letter to avoid unexpected findings of unacceptable interference.

Compliance requires a disciplined combination of measurement, modelling, record-keeping and operational controls tied to the Determination’s text. Below are concrete steps an operator or compliance officer should follow, citing the relevant instrument provisions for each task.

1. Confirm scope and classify device type

   • Confirm the transmitter is a fixed transmitter in the 2.5 GHz band as defined (section 5 definitions of fixed transmitter, 2.5 GHz lower band, upper band). If mobile or exempt under subsection 69(2) of the Act, different rules may apply (note to section 10).
   • Determine whether the transmitter incorporates an Active Antenna System (AAS). This affects LOP (Schedule 2, item 2) and RP calculation (Schedule 2, item 2 Note 1).

2. Obtain authoritative datasets and standards

   • Use the DEM-3S dataset cited in the Determination (section 5 definition of DEM-3S) and obtain the persistent-identifier dataset from Geoscience Australia.
   • Use GDA94 for geodetic coordinates (section 5).
   • Use the Radio Regulations to determine emission designators where required (section 7).

3. Accurately measure site location and antenna height

   • Measure the location (latitude and longitude, GDA94) of the antenna phase centre to an error less than 10 metres (Schedule 1 item 3(3)).
   • Measure vertical antenna height hgt with an error less than 5 parts in 100 (Schedule 3 item 1(1)(a)). Document the measurement method and instrument calibrations.

4. Calculate effective antenna height (he) per Schedule 3

   • Compute hs = DEM-3S cell height at location + hgt (Schedule 3 item 1(1)(b)), with the special modulus rule if the seconds component plus 1.5 has modulus zero when divided by 3 (Schedule 3 item 1(3)).
   • Compute average ground height hagm at each m-increment and radial per Schedule 3 item 2: identify DEM-3S cell, bound with adjacent 8 cells, average the 3 × 3 grid heights. Apply the modulus exception in Schedule 3 item 2(2) where applicable.
   • Compute he per Schedule 3 item 1(1)(d)-(e). For groups of transmitters, use the greatest hgt among the group (Schedule 3 item 1(2)).

5. Prepare RP inputs

   • Determine maximum true mean power and occupied bandwidth within the licence band using good engineering practice measurement methods described in section 5 definition notes (adjacent channel power meter or spectrum analyser).
   • Determine antenna gain pattern in the horizontal plane (dBi) at each azimuth σn. For AAS, calculate the RP using the sum of total radiated power and the antenna gain towards the horizontal plane and azimuth σn, and ensure there is operational control to prevent RP exceedance (Schedule 2, item 2 Note 1).

6. Compute propagation loss PL(lmn, Lmn)

   • For each radial n = 0...359 and each increment m = 1...400 (i.e. 100 m, 200 m, ... 40 km), compute the geodesic coordinate (lmn, Lmn) using Vincenty’s Direct Formulae per Schedule 3 item 3. Use the specified GRS80 parameters.
   • For each increment, compute the propagation-loss value PL(lmn, Lmn) following Schedule 2 item 3’s steps (including the required parameter calculations and the propagation-loss formula steps supplied in the Schedule).

7. Apply device boundary criterion and determine device boundary

   • For each radial, evaluate RP - MP at each m×100 m increment, with MP = PL(lmn, Lmn) + LOP − Gr (Schedule 2 item 2).
   • Use LOP = −108 dBm/30 kHz for AAS, −116 dBm/30 kHz for others (Schedule 2 item 2).
   • Gr is the nominal receiver antenna gain including feeder loss set to 0 dBi (Schedule 2 item 2).
   • Identify the first increment where RP - MP ≤ 0; that increment’s latitude/longitude is the radial end point. If none is found within 400 increments, the 400th increment is the end point (Schedule 2 item 1).
   • Assemble the 360 end points to form the device boundary polygon (Schedule 2 item 1).

8. Check geographic area and bright-line limits

   • Confirm the device boundary lies within the licence geographic area. If any part lies outside, section 10(1)(b) deems the interference unacceptable unless the narrow exception in section 10(2) applies.
   • Ensure emissions above the horizontal plane are ≤ 45 dBm/30 kHz EIRP (section 10(3)).
   • If operating in the lower band (2500-2570 MHz), ensure effective antenna height ≤ 10 metres (section 10(4)).

9. Document statistical confidence and measurement uncertainty

   • For parameters in Schedules 2 and 3, produce evidence that estimates meet not less than 95% confidence that the true value will remain below the specified requirement (section 11). Document methodology, sample sizes, model assumptions, uncertainty quantification, and instrument calibration certificates.

10. Register compliance and manage changes

• Provide the ACMA with Register entries in accordance with the Act and section 144 requirements (notes to sections 8 and 9). Include antenna identification numbers and other required fields.
• For transmitters included in the Register before commencement, note transitional protection (section 12). If you intend to change registered details, calculate old and new device boundaries on each radial before recording the change , if new boundaries are equal to or less than old on each radial, transitional protection is preserved (section 12(3)).

11. Operational controls and AAS-specific steps

• If using an AAS and relying on the Determination’s AAS assumptions, document control logic and worst-case beam/power states that demonstrate RP will not be exceeded under any permitted operating state (Schedule 2 item 2 Note 1).
• Implement power control and beam management workflows to prevent transient exceedance of RP and to avoid emissions above the horizontal plane exceeding 45 dBm/30 kHz EIRP (section 10(3)).

12. Maintain records for potential ACMA review

• Retain modelling inputs (DEM-3S extracts, geodetic calculations, Vincenty formula implementations), measurement raw data, calibration certificates, and the uncertainty analyses substantiating the 95% confidence statement (section 11). The Determination does not describe ACMA’s audit process, so keep complete documentation.

13. Where advice is needed

• If in doubt about the interpretation of the modulus exceptions, the DEM-3S cell selection rules, the implementation of Vincenty formulae, or the AAS assumptions, seek technical advice from RF consultants experienced with the Determination’s exact methods, and seek legal advice on Register and Act compliance, since enforcement stems from the Act.

Following these steps aligns operational practice with the Determination’s detailed prescriptions (section 5, Schedule 2 and Schedule 3) and positions licensees to demonstrate to the ACMA that their transmitters do not cause an “unacceptable level of interference” as defined in section 10.