Radiocommunications (Interpretation – Technical Framework) Determination 2024

The Determination sets out a set of recurring technical and administrative concepts that the ACMA and industry must use consistently across specified instruments. Those concepts are central to practical compliance and to administrative determinations made under the Radiocommunications Act 1992.

Dictionary and scope: The Dictionary in Schedule 1 defines expressions for this Determination, instruments made under subsection 145(4) of the Act and advisory guidelines under subsection 262(1) of the Act (cl 4(1)). If an instrument specified in cl 4(1)(b) or (c) defines an expression itself, the Dictionary does not define that expression for the purposes of that instrument (cl 4(2)). In addition, any expression already defined in the Act retains the same meaning in the Dictionary (cl 4(3)). The Dictionary therefore functions as a default, backstopping technical meanings unless an implementing instrument provides its own definition.

Geodetic and data standards: Locations and coordinates must be given with reference to GDA94 (Dictionary entries for location and GDA94), and the Determination prescribes the use of the DEM-3S elevation dataset from Geoscience Australia for terrain heights (DEM-3S definition, with persistent identifier). The Australian Spectrum Map Grid and the HCIS (hierarchical cell identification scheme) are referenced for area descriptions.

Signal parameters and measurement philosophy: Several core measurement terms are defined precisely: centre frequency, occupied bandwidth (containing 99% of true mean power), true mean power, mean power (measured over a time interval at least ten times the period of the lowest modulation frequency), maximum true mean power and horizontally radiated power (sum of maximum true mean power in dBm per specified rectangular bandwidth at the antenna connector and the antenna gain in dBi in a specified horizontal direction). The Determination requires that emission designators be determined using the methods in the ITU Radio Regulations, with “necessary bandwidth” read as “occupied bandwidth” (cl 2).

Grouping and identity: The Determination provides rules for when fixed transmitters or receivers are treated as groups (cls 3-4). Group membership requires identical centre frequency and emission designator, common intended communication endpoints, identical antenna make/model, co-location within 20 metres of phase centres on the same structure, and identical ACMA antenna identification number. A transmitter or receiver cannot belong to more than one group (cls 3(2), 4(2)).

Effective antenna height algorithm: Schedule 2 gives a multi-step algorithm for calculating effective antenna height of fixed transmitters. The algorithm uses hgt (vertical height of the antenna phase centre above a defined point on the supporting structure), hs (hgt plus the DEM-3S cell height at the transmitter’s location), and an average ground height computed from DEM-3S cells around sample points defined by radials and increments. Vincenty’s Direct Formulae are mandated to compute geographic coordinates for sampling points (Schedule 2 items 1-3). There are specific numerical tolerances: hgt must be measured with error < 5 parts in 100 (i.e. <5%), and location sampling must use DEM-3S cells and 3×3 averaging; a special cell-selection rule applies when a sampling coordinate lies on a DEM-3S cell boundary (see Schedule 2 item 2(2)).

Accuracy and conservative bias: The instrument imposes an accuracy obligation: unless otherwise specified, any parameter in Schedule 2 must be estimated with a level of confidence not less than 95 per cent that the true value will always remain below the requirement specified in the instrument (cl 6). That wording instructs estimates to be made conservatively (ensuring with 95% confidence that true values do not exceed required limits).

Reference and continuity rules: References to other legislative instruments are to be read as references to those instruments as in force from time to time, and references to other kinds of instruments or writing are similarly to be read as existing from time to time (cl 5). The Determination also cross-refers to the Act (including s 144 Register requirements and s 32 frequency band plans), the Seas and Submerged Lands Act 1973 for territorial sea baselines, and the ITU Radio Regulations.

Taken together, these concepts create a technical standard-setting function: the Determination tells ACMA staff and regulated parties the exact datasets, geodetic parameters, formulae, tolerances and procedures to use when reporting locations, antenna heights and emission characteristics for the purposes of spectrum administration and advisory materials.

The Determination applies to a set of actors and instruments explicitly identified in the text. Primary parties affected are spectrum licensees and operators of radiocommunications devices, ACMA as regulator, and anyone preparing instruments or advisory guidelines under the referenced sections of the Radiocommunications Act.

Directly affected entities and roles:

• Spectrum licensees and authorised third parties who operate radiocommunications transmitters and receivers under a spectrum licence or apparatus licence, because the Dictionary and measurement methods will be used in instruments made under subsection 145(4) of the Act and in advisory guidelines under subsection 262(1) (cl 4(1)).
• Owners/operators of fixed transmitters and fixed receivers, because the Determination prescribes how to identify locations (antenna phase centres) and how to calculate effective antenna height for fixed transmitters (Schedule 2 items 1-3; cl 5 on location).
• Entities that declare groups of transmitters or receivers for Register purposes, because the Determination sets out the criteria for group membership and prevents multiple group membership (cls 3(1)-(2); 4(1)-(2)).
• Parties that must determine emission designators for transmitters, because the Determination requires use of the Radio Regulations and specifies that “necessary bandwidth” be read as occupied bandwidth (cl 2).
• Technical consultants, RF engineers and measurement laboratories who will carry out measurements and modelling, because the Determination mandates specific datasets (DEM-3S), geodetic datum (GDA94), formulae (Vincenty) and confidence levels (cl 6).
• ACMA staff who maintain the Register and issue site identifiers, because the Determination informs what information is to be included and how it is to be measured and represented (notes referencing s 144 and the ACMA’s issuance of site identifiers).

Indirectly affected parties:

• Manufacturers of antennas and equipment where antenna identifiers and antenna data feed into group definitions and Register entries, because the Determination requires identical antenna type, model and manufacture and the same ACMA antenna ID for group membership (cls 3(1)(c),(e); 4(1)(b),(d)).
• Users of spectrum planning data and mapping (for example, parties relying on the Australian Spectrum Map Grid and HCIS identifiers), since the Determination references these for area descriptions.
• Operators whose systems might border spectrum licence geographic or frequency boundaries, because the instrument defines emission buffer zones in the Dictionary and defines in-band and out-of-band in operational terms, which will affect containment of radio emissions.

Decision-makers and authorities:

• ACMA is identified as the maker of this instrument (cl 3) and is the authority that issues site identifiers and maintains the Register (notes and cl 5 references). The instrument also references the ITU Radio Regulations and Geoscience Australia datasets as sources to be used by regulated parties; ACMA is therefore delegating standardised data and formula usage by reference.

The Determination therefore affects technical practice across licence holders, technical consultants, equipment manufacturers and ACMA itself. The scope is purposive and technical rather than directly regulatory of behaviour; nevertheless, adherence will be required where Register entries, spectrum licence conditions or advisory guidelines adopt these definitions and methods (cl 4(1)).

The Determination imposes technical duties and creates entitlements to use defined methods and datasets; it does not itself create fee rights or new licence conditions, but it constrains how ACMA and regulated parties must measure and describe certain characteristics where the Determination is adopted into other instruments.

Key duties (express in the instrument):

• Use the Dictionary definitions for instruments specified in cl 4(1), unless those instruments provide their own definitions (cl 4(1)-(2)). This is a duty on drafters of subsidiary instruments and on regulated parties when those instruments apply.
• Determine emission designators by the methods in the ITU Radio Regulations and treat “necessary bandwidth” as “occupied bandwidth” (cl 2(1)-(2)). This binds technicians and registrants to a particular method for labelling emissions.
• When treating transmitters or receivers as a group, satisfy the enumerated criteria: same centre frequency and emission designator, common communication counterpart, same antenna model/manufacturer and ACMA antenna identification, located on the same structure within 20 metres of phase centres (cls 3(1), 4(1)). There is also a negative duty: a radiocommunications transmitter or receiver must not belong to more than one group (cls 3(2), 4(2)).
• Provide locations as GDA94 latitude/longitude of the antenna phase centre and ensure measurement error for location is less than 10 metres (cl 5(1)-(5)).
• For effective antenna height measurements: measure hgt with an error less than 5 parts in 100; compute hs and then effective antenna height using the DEM-3S cell height and the average ground height computed by the specified radial-and-increment procedure; apply the special-case rules where the seconds component condition is met or where hs minus average ground height is less than hgt (Schedule 2 item 1(1)-(3)).
• Use DEM-3S and the specific persistent identifier for that dataset when calculating effective antenna heights (DEM-3S definition).
• Apply Vincenty’s Direct Formulae with the specified GRS80 constants and iterate until change in φ is less than 10^-12 in computing sampling coordinates (Schedule 2 item 3).

Accuracy duty:

• Unless otherwise specified, estimate Schedule 2 parameters with a level of confidence not less than 95 per cent that the true value will always remain below the requirement specified in this instrument (cl 6). This creates an evidential standard for parameter estimation.

Rights and entitlements:

• Instruments that adopt this Dictionary or follow its methods can rely on its definitions and prescribed algorithms as the official ACMA interpretation for the purposes listed in cl 4(1). That gives certainty to registrants and advisers about the official technical baseline to be used for Register entries, spectrum licensing instruments under s 145(4), and advisory guidelines under s 262(1).
• Where a transmitter or receiver could belong to more than one group, the instrument allows the spectrum licensee or authorised third party to nominate one group membership (notes to cls 3 and 4). That provides an administrative right to select which group to declare.

What the Determination does not do:

• It does not itself create criminal or civil penalties within its text. The Determination is an interpretative instrument authorised under the ACMA Act (cl 3). Enforcement consequences would arise only insofar as other instruments (spectrum licences, apparatus licences, the Act) adopt these definitions or require conformance with them; the Determination does not itself state penalties for non-compliance.

In practice, these duties require technical measurement procedures, record-keeping of dataset versions and site identifiers, and possible administrative steps to nominate group membership where ambiguous. The entitlements are primarily legal certainty for parties about the definitions and procedures ACMA expects where this Determination applies.

The Determination itself is an interpretative legislative instrument and does not on its face create offences or prescribe specific penalties. It is made under subsection 64(1) of the Australian Communications and Media Authority Act 2005 (cl 3) and supplies definitions and measurement methods to be used in instruments made under the Radiocommunications Act 1992 (cl 4(1)). Enforcement and penalties therefore arise from two mechanisms implicit in the text:

1. Adoption by operative instruments: The Dictionary and measurement methods apply to instruments made under subsection 145(4) of the Act and to advisory guidelines under subsection 262(1) (cl 4(1)). Where a spectrum licence, apparatus licence, spectrum plan, or other instrument adopts or references this Determination, compliance with its definitions and measurement methods will be a condition or expectation underpinning regulatory obligations in those operative instruments. Penalties and enforcement then follow from the relevant provisions of the Radiocommunications Act 1992, the particular licence conditions and any sanctions that Act confers for contraventions of licence conditions. The Determination itself does not specify those sanctions.

2. Administrative consequences via the Register and ACMA actions: The Determination standardises how information is recorded in the Register (note referencing s 144 and the ACMA’s issuance of site identifiers). Misreporting or failure to provide data in the required format may result in administrative action by ACMA under the Act or under licence conditions that require accurate Register entries. Again, any enforcement powers would come from the Act or the terms of a licence or instrument that incorporates this Determination.

Operational obligations that create enforcement risk if not met:

• Measurement tolerances and accuracy requirements: The Determination requires that location measurements have an error less than 10 metres (cl 5(5)); that hgt be measured with error less than 5 parts in 100 (Schedule 2 item 1(1)(a)); and that Schedule 2 parameter estimates have 95 per cent confidence that the true value will remain below the instrument’s requirement (cl 6). Failure to meet these specified measurement requirements could be treated as non-compliance in contexts where a licence or Register entry requires adherence to the Determination.
• Use of specified datasets and methods: The Determination mandates DEM-3S for terrain heights (DEM-3S definition with PID) and Vincenty’s Direct Formulae with specified constants and iteration tolerance for coordinate computations (Schedule 2 item 3). Use of alternative datasets or formulae where an instrument requires this Determination could trigger administrative challenge or refused acceptance of data in the Register.

What enforcement steps or penalties might occur is not listed in the Determination itself. Any penalty would therefore be those available under the Radiocommunications Act 1992, the ACMA Act, or specific licence instruments that incorporate or refer to this Determination. The Determination’s practical enforcement effect is to set the technical baseline ACMA will accept; divergence from that baseline where binding instruments require it will expose a licence-holder or registrant to whatever compliance and enforcement mechanisms the operative law provides.

The Determination is explicitly framed to operate in concert with other legislative instruments and underlying Acts. It is an interpretative instrument that supplies definitions and methods to be used in specified contexts under the Radiocommunications Act 1992 and ACMA’s functions under the ACMA Act 2005.

Key statutory interactions identified in the text:

• Radiocommunications Act 1992: The Dictionary states that expressions defined in the Act have the same meaning in the Determination (cl 4(3)), and the Determination is intended to be used in instruments made under subsection 145(4) of that Act and in advisory guidelines made under subsection 262(1) (cl 4(1)). The Determination therefore operates as an interpretative aid for instruments, licences, and plans made under the Radiocommunications Act.
• Australian Communications and Media Authority Act 2005: The Determination is made under subsection 64(1) of the ACMA Act (cl 3). ACMA’s authority to make such determinations flows from that Act. The Determination also references section 65 of the ACMA Act as a relevant cross-reference (cl 5 note 3).
• Acts Interpretation Act 1901 and Legislation Act 2003: The Determination’s cl 5 notes refer users to section 10 of the Acts Interpretation Act 1901 for references to Commonwealth Acts and to subsection 13(1) of the Legislation Act 2003 for the application of the Acts Interpretation Act 1901 to legislative instruments. This establishes interpretive continuity with general Commonwealth statute construction rules.
• Seas and Submerged Lands Act 1973: The Determination references the “Australian territorial sea baseline” as the baseline from which territorial sea breadth is measured under section 7 of that Act (Dictionary). That reference is pertinent to geographic areas for spectrum licences that may extend over sea areas.
• Spectrum plan and Radio Regulations: “Harmful interference” is given the meaning provided by the spectrum plan (Dictionary), and emission designators are to be determined using ITU Radio Regulations methods (cl 2). The instrument instructs that the Radio Regulations’ “necessary bandwidth” is to be read as “occupied bandwidth” (cl 2(2)). The Determination thus harmonises domestic administrative definitions with international regulatory definitions for technical parameters.
• Register requirements: The Determination notes section 144 of the Act regarding the information that must be included in the Register about spectrum licences and radiocommunications devices and acknowledges that ACMA issues site identifiers (notes to cls 3-5). The Determination therefore feeds into statutory record-keeping duties.

How references are to be read:

• The Determination says that references to other legislative instruments are to be read as those instruments “as in force from time to time”, and references to other kinds of instruments or writings are to be read as “in force or existing from time to time” (cl 5). This creates dynamic incorporation of later amendments to referenced instruments, meaning the Determination does not freeze the meaning of referenced instruments to their status on the commencement date.

Limits of interaction:

• The Determination does not itself amend the Radiocommunications Act 1992, nor does it purport to override other instruments that define a term differently for a particular instrument (cl 4(2)). Where a specific instrument defines a term, that instrument’s definition prevails for its own purposes.

In short, the Determination functions as a technical annex to the Radiocommunications Act regulatory framework and to ACMA instruments, providing definitional and computational standards that integrate with the Act’s licensing, register and spectrum plan provisions. Its practical legal effect depends on whether and how other operative instruments incorporate it, and references are designed to pull in updated instruments and datasets over time.

The text supplied contains the instrument as made and the commencement date; it does not include prior versions, amendments or a legislative history beyond those particulars.

Concrete facts in the instrument about its creation and status:

• The Determination is titled Radiocommunications (Interpretation - Technical Framework) Determination 2024 (cl 1).
• It commenced on 31 March 2024 (cl 2).
• It was made under subsection 64(1) of the Australian Communications and Media Authority Act 2005 (cl 3).

No further amendments or repeal provisions are set out in the text provided. There is no schedule listing previous instruments that this instrument replaces, nor is there a history of earlier determinations included in the material presented. The Dictionary notes that certain expressions cross-reference definitions in the Radiocommunications Act 1992 (for example, apparatus licence, spectrum licence, spectrum plan), but the Determination does not indicate any prior Determination that it supersedes.

How to read this for amendment risk and practical upkeep:

• The instrument’s cl 5 establishes that references to other legislative instruments are dynamic, read “as in force from time to time” (cl 5). That mechanism imports amendment risk from referenced instruments, for example the Radio Regulations, the spectrum plan, or class licences such as the Radiocommunications (Low Interference Potential Devices) Class Licence 2015 (LIPD class licence), which the Dictionary treats as current until replaced (LIPD definition).
• The DEM-3S dataset is cited by a persistent identifier (PID) and a specific bibliographic citation. That PID gives a static anchor to the dataset version cited; but the Dictionary also notes that DEM-3S is available from Geoscience Australia and that further information about it is available online. If Geoscience Australia replaces DEM-3S with a new dataset, an amendment to the Determination or a replacement instrument may be required for ACMA to alter the mandated dataset. Until amended, market participants are obliged to use the specified DEM-3S citation.

Because the provided material contains only the instrument as made, the amendment history is limited to the instrument’s making date and the commencement date. Any subsequent amendments, revocations or replacement instruments are not included in the supplied text and therefore cannot be reported here.

The Determination text supplied contains no judicial decisions, litigation references or legal proceedings concerning this instrument. It contains notes mentioning statutory provisions (for example, section 144 of the Radiocommunications Act 1992) and references to international instruments (the ITU Radio Regulations), but there is no mention of any case law, disputes or judicial consideration.

What the absence of litigation references means for users:

• There is no judicially-determined interpretation of the specific clauses, special-case rules (for example, the seconds component modulus rule for DEM-3S cell selection), or the application of the Determination to particular factual scenarios recorded in the instrument text supplied.
• Where disputes arise about the meaning or application of these definitions and methods, resolution will depend on the text of the Determination itself, any instrument incorporating it, and judicial interpretation of those instruments under the Radiocommunications Act and related statutes. This Determination provides a technical baseline that a court would likely treat as an authoritative administrative specification, but there is no precedent in the provided material.

Practical implication:

• Regulated parties should treat the Determination as operative technical guidance that informs compliance and Register entries. In the absence of litigation history, reasonable compliance planning should focus on implementing the methods and tolerances specified (for example, using DEM-3S, applying Vincenty formulae, achieving measurement error bounds, and documenting confidence intervals) to reduce the risk of dispute when ACMA validates Register entries or licence compliance.

Because the Determination is newly commenced (31 March 2024) per the text provided, litigation, if any, would post-date that commencement and is not documented in this instrument.

The Determination contains several technical specifics and special-case rules that create potential traps for practitioners who implement its prescriptions mechanically. These “gotchas” are concrete rules or requirements in the text that are easy to miss, and that affect the validity of measurements, groupings and Register entries.

1. Dictionary only a default: The Dictionary applies to this instrument, instruments under s 145(4) and advisory guidelines under s 262(1) (cl 4(1)). But if an instrument defines an expression itself, the Dictionary does not define it for that instrument (cl 4(2)). Practitioners must check the operative instrument for bespoke definitions rather than assuming the Dictionary always applies.

2. “Necessary bandwidth” redefined: The Determination instructs that, for emission designators determined via the Radio Regulations, references to “necessary bandwidth” should be read as references to “occupied bandwidth” (cl 2(2)). If an operator or consultant uses a Radio Regulations methodology that treats “necessary bandwidth” differently, they must instead apply the occupied bandwidth definition (99% of true mean power) defined in the Determination.

3. Group membership requires identical ACMA antenna ID: One of the grouping criteria is the “identification number assigned by the ACMA to the antenna used with each radiocommunications transmitter” being the same (cl 3(1)(e) and 4(1)(d)). Where a single physical antenna is used by multiple transmitters but ACMA-assigned antenna IDs differ (for example, due to separate Register entries), that could prevent group treatment. Conversely, identical IDs across spatially separated installations may implicate grouping, so practitioners must reconcile ACMA antenna IDs with physical topology.

4. Strict co-location tolerance: Group members must be on the same structure and within 20 metres of the phase centres of other antennas in the group (cl 3(1)(d); 4(1)(c)). Small errors in phase-centre coordinate measurement could alter whether devices qualify as a group. Coordinate measurement error must be less than 10 metres (cl 5(5)), so the tolerance window for group membership is relatively tight.

5. Measurement error thresholds and relative measurement error for hgt: The Determination sets an absolute tolerance for location measurement error (<10 metres) (cl 5(5)), and a relative tolerance for hgt measurement error of less than 5 parts in 100 (Schedule 2 item 1(1)(a)). Practitioners must implement measurement and calibration protocols capable of meeting both absolute and relative thresholds and document uncertainty.

6. DEM-3S cell handling and boundary rule: Average ground height is computed by identifying the DEM-3S cell of a sampling coordinate and averaging the 3×3 matrix of that cell and surrounding cells (Schedule 2 item 2(1) Steps 2-4). A special rule applies if the seconds component of the sampling coordinate, plus 1.5, has a modulus of zero when divided by 3; then, for Step 2, the corresponding DEM-3S cell is the adjacent DEM-3S cell with the minimum height (Schedule 2 item 2(2)). This unusual selection criterion means that points falling on certain grid boundaries must treat the cell differently, and failure to implement this exact rule will produce a different average ground height and therefore a different effective antenna height.

7. Seconds-component rule for hs too: A similar special rule applies when the seconds component of the transmitter’s latitude or longitude, plus 1.5, has a modulus of zero when divided by 3: hs is then computed using the maximum height of the adjacent DEM-3S cells rather than the DEM-3S cell at the location (Schedule 2 item 1(3)). That creates a discontinuity in hs computation for specific coordinate values.

8. Conservative confidence wording: Clause 6 requires parameters in Schedule 2 to be estimated with at least 95 per cent confidence that the true value will always remain below the requirement specified. The phrase “always remain below the requirement” implies a conservative bias in estimation. Practitioners must interpret this as requiring a statistically supportable upper-confidence bound (for example, one-sided 95% interval) and document the method used to reach that confidence level.

9. Vincenty iteration tolerance: The Determination mandates iterative calculations for Vincenty’s Direct Formulae until the change in φ is less than 10^-12 (Schedule 2 item 3(2)). Implementations using coarser tolerances or different geodetic constants may produce coordinate discrepancies. The instrument also specifies parameters a and fl (GRS80) and that b = a×(1-fl); these constants must be used to match ACMA’s intended coordinates.

10. Requirement to use GDA94: Locations must be given with reference to GDA94 (cl 5(1)-(4) and Dictionary). Modern GNSS receivers and mapping services default to later datums (for example, GDA2020 in Australia), so converting coordinates properly to GDA94 is necessary and can introduce small differences if not handled correctly.

11. Occupied bandwidth defined as 99% of true mean power: Occupied bandwidth is defined as the frequency range containing 99% of the true mean power of emissions. Measurement procedures for determining 99% containment require appropriate instrumentation and analysis (e.g. spectrum analysis with adequate integration and filter considerations). The Note in the definition reminds users that power measurement normally uses adjacent channel power meters or spectrum analysers and that estimation of accuracy should be in accordance with good engineering practice.

12. Group nomination when multiple possible groups: If a transmitter or receiver is capable of belonging to more than one group, the spectrum licensee or authorised third party may nominate one group (notes to cls 3 and 4). Practitioners should ensure nomination is documented and consistent with Register entries.

These items are specific, operational elements that require careful technical implementation. Small deviations from the letter of the Determination will change derived values such as effective antenna height, group membership status, and emission designator assignments.

Complying with the Determination requires a programme combining data, measurement protocols, calculation software and record-keeping. The steps below translate the Determination’s prescriptions into actionable compliance tasks and points of attention.

1. Governance and instrument mapping

• Identify where this Determination applies to your licences or obligations: check whether your spectrum licence, apparatus licence, spectrum plan, or advisory guidelines reference this Determination or the classes of instruments in cl 4(1). If an instrument defines its own terms superseding the Dictionary, document that divergence (cl 4(2)).
• Where a transmitter or receiver could belong to multiple groups, plan to exercise the spectrum licensee’s right to nominate a single group and record the nomination in licence or Register documentation (notes to cls 3 and 4).

2. Data and datum handling

• Use GDA94 for all latitude/longitude coordinate reporting (cl 5(1)-(4) and Dictionary). If your GNSS equipment uses another datum, convert coordinates to GDA94 using validated geodetic transformation methods and record the conversion method.
• Acquire the DEM-3S dataset using the persistent identifier cited in the Determination and use the dataset version specified (DEM-3S definition). Keep a copy or a clear record of the version and PID used, so you can demonstrate consistency with the Determination.

3. Measurement equipment and uncertainty

• Ensure measurement equipment and protocols can meet the specified error tolerances:
  • Location measurement error < 10 metres (cl 5(5)).
  • Antenna phase-centre vertical height (hgt) measured with error < 5 parts in 100 (Schedule 2 item 1(1)(a)).
• Maintain calibration records for measurement tools (GNSS receivers, total stations, height-measurement devices, spectrum analysers).
• For power and occupied bandwidth measurements, use adjacent channel power meters or spectrum analysers and document filter correction factors, bandwidth settings and time integration used in accordance with “good engineering practice” (Note in maximum true mean power and occupied bandwidth definitions).

4. Implementing effective antenna height calculations

• Compute hgt as defined: vertical height in metres of the phase centre measured relative to the point on the supporting structure where it intersects the ground or sea surface that has the lowest elevation on that intersection line (Schedule 2 item 1(1)(a)(i)-(ii)). Document the reference point and the measurement protocol.
• Compute hs = DEM-3S cell height at the transmitter location + hgt, subject to the special-case rule in item 1(3) if the seconds component of the latitude or longitude (plus 1.5) has a modulus of zero when divided by 3. In that special case, use hgt plus the maximum height of adjacent DEM-3S cells.
• Compute average ground height for each m-increment on each n-radial using the Step 1-4 process in Schedule 2 item 2(1): use Vincenty’s Direct Formulae (Schedule 2 item 3) to determine coordinates for the sampling point; identify the DEM-3S cell containing the sampling point; build the 3×3 matrix of the cell and adjacent cells and average the nine DEM-3S cell height attributes.
• Implement the boundary rule from Schedule 2 item 2(2): when the seconds component of a sampling coordinate plus 1.5 has modulus zero divided by 3, identify for Step 2 the adjacent DEM-3S cell with the minimum height and use its 3×3 matrix average.
• Compute the effective antenna height he_m using hs minus the average ground height computed above, except if hs minus average is less than hgt, in which case he_m = hgt (Schedule 2 item 1(1)(d)-(e)).
• For groups of transmitters, take hgt as the greatest hgt among members (Schedule 2 item 1(2)).

5. Vincenty formula implementation

• Implement Vincenty’s Direct Formulae as set out in Schedule 2 item 3, using the specified parameters a = 6,378,137 m and flattening fl = 1/298.25722210 with b = a×(1-fl). Iterate the φ update until change is < 10^-12 (item 3(2)). Use four-quadrant inverse tangent (atan2) where specified.
• Validate your implementation against test points and document iteration tolerances and convergence characteristics.

6. Emission designator and occupied bandwidth

• Determine emission designators via the ITU Radio Regulations methodology, applying occupied bandwidth (99% containment of true mean power) where the Radio Regulations refer to necessary bandwidth (cl 2). Document the procedure used to compute the occupied bandwidth and the instrumentation settings that demonstrate 99% containment.

7. Group and Register management

• Verify antenna type, model, manufacture and ACMA antenna identification numbers before declaring group membership (cls 3-4). Where multiple possible groups exist, make and document a nomination (notes).
• Ensure Register entries use the antenna phase-centre coordinates (GDA94) and that error estimates and dataset versions are recorded. Keep ACMA site identifier records in the Register as ACMA issues them (note referencing s 144).

8. Statistical confidence and conservative estimation

• For Schedule 2 parameter estimates, adopt a statistical approach that produces a one-sided 95% confidence interval guaranteeing that the true value will remain below the specified requirement, and document the statistical method used (cl 6). For example, if a parameter is subject to measurement and modelling uncertainty, compute an upper confidence bound that meets the 95% one-sided criterion and use that value for compliance comparators.
• Keep records of uncertainty analyses, measurement repetition, and modelling assumptions to support the 95% confidence claim.

9. Documentation, audit trail and change control

• Maintain an audit trail of all inputs: DEM-3S PID and version, date-stamped coordinate measurements (with equipment logs), Vincenty algorithm implementation parameters and iteration tolerance, spectrum analyser settings for occupied bandwidth, antenna identification numbers, and group nomination records.
• When systems or datasets change (for example, if you upgrade GNSS equipment or adopt a new DEM dataset), record the change, date, and rationale and evaluate whether any Register entries or licence conditions must be updated in light of cl 5 which pulls in instruments “as in force from time to time”.

10. Practical checks and validation

• Cross-check effective antenna height outputs against physical measurements and site surveys to ensure no gross errors (for example, check that he_m is not unintuitively small or large).
• Where location coordinates lie close to the seconds-component grid that triggers the special-case rules, independently verify DEM-3S cell selection and document which adjacent cell was chosen under Schedule 2 item 2(2) or item 1(3).

By following these steps, regulated parties can demonstrate that they used the datasets, formulae and tolerances specified in the Determination and that parameter estimates meet the 95% confidence requirement. Proper documentation is crucial because the Determination’s effect in practice arises where other instruments rely on it, and ACMA will expect submissions and Register entries to conform to these prescriptive methods.