Recommendations for the ARPANSA EME prediction methodology
This information is intended mainly for the guidance of those preparing ARPANSA Environmental EME reports.
The ARPANSA EME Prediction Methodology has been reviewed to incorporate changes required by:
- new installation practices
- the current ARPANSA Environmental EME Report format.
In the interests of uniformity, ARPANSA recommends that the following parameters and assumptions be used when calculating EME levels for presentation in the ARPANSA Environmental EME Report.
The aim of these recommendations is to maintain the ARPANSA EME Report as a reasonable near worst-case estimate of line-of-sight exposure levels for full-power operation without producing a gross overestimate.
Antenna Input Power
Recommendations for power levels for common configurations are provided on the Mobile Carriers Forum (MCF) National Site Archive website (RFNSA). It is recommended that wherever applicable, the power levels given in the RFNSA MCF EME RF Compliance Strategy (MERCS) document 'MCF Std mobile system pwrs antenna config' (as updated from time to time) be used. These power levels use maximum nominal power amplifier outputs and make allowance for cable and combine losses in a conservative way.
Antenna Tilt Parameters
It is recommended that a composite antenna pattern covering electrical tilts of 0° – 6° be used whenever the design electrical tilt is within this range. If the design electrical tilt exceeds 6°, the actual tilt value should be used in the calculation. Actual values for mechanical tilt should be used.
Measured antenna patterns obtained as close as possible to the operational frequency should be used. Where possible, maximum 'envelope' patterns, which fill in nulls in the vertical cut and which take into account frequency variations, should be used.
Assessment Frequencies for ARPANSA RPS3 Public Limits
The Public Exposure limits in the ARPANSA radiation protection standard RPS3 increase with frequency, or are constant, over the frequency bands of use by mobile phone base stations. A standardised frequency on the low side of the actual frequency band should be used in computing the public limits. Hence for:
- GSM900, LTE900 or WCDMA900 use 900 MHz
- GSM1800 or LTE1800 use 1800 MHz
- LTE 2100 or UMTS2100 use 2100 MHz
- WCDMA in the frequency range of 870 MHz to 900 MHz, a nominal 900 MHz may be used but for lower frequencies an appropriate conservative lower band edge frequency should be used.
Reference Plane and Height Datum for Predictions
The primary estimates of EME are to be made at 1.5 m above ground level, presumed to be flat and level with the 'base' of the antenna supporting structure, be it a self-supporting tower or a building serving another purpose. The height datum at the base of the antenna supporting structure should be chosen to be representative of the ground on which the public may walk or sit in the vicinity of the antenna. It should not be an artificially low level that might occur when the tower or building is sited in a depression or in an area of excavated land such as might be used to give access to a basement. It is accepted that actual ground levels may slope upwards in one or more directions away from the supporting structure. This does not require re-assessment of the height datum but may require special consideration in the 'Other Areas of Interest' section of the ARPANSA Environmental EME report.