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Commentary on base station RF survey results

All measurements collected in this survey are well below the limits defined by the current ARPANSA Standard RPS3.

The largest extrapolated RF EME level was found at Lennox Head where 3.43% of the general public exposure limit defined by RPS3 was recorded. This value is approximately 29 times less than the permitted exposure level under the current standard.

The largest measured levels of RF EME were also found for the Lennox Head site where a value of 0.54% of the general public exposure limit defined by RPS3 was measured (around 185 times below the limit defined by the standard).

The antennas at Lennox Head were mounted on the side of a water tank and were relatively close to the ground in comparison to many of the other sites where the antennas are mounted high up on concrete monopoles or steel lattice towers. This is one reason why the measured values were comparatively larger at these sites.

The graphs in the following figures compare the observed and predicted RF EME levels as a percentage of the general public limit of the ARPANSA Standard RPS3. Note that the data for Lennox Head does not appear on the first graph as it is off the scale.

Comparison, using a linear scale, of observed and predicted RF EME levels as a percentage of the general public limit of the ARPANSA Standard RPS3.

Predicted % of RPS3

Red Squre indicator Measured and Blue diamond indicator Extrapolated values on a linear scale. Open diamonds indicate extrapolation from demodulated pilot signals. Filled diamonds indicate extrapolation from analogue measurements. Symbols above the diagonal black line indicate sites where extrapolated measurements exceeded the predicted maximum values.

Comparison, using a logarithmic scale, of observed and predicted RF EME levels as a percentage of the general public limit of the ARPANSA Standard RPS3.

Predicted % of RPS3

Red square indicator Measured and Blue Diamond indicator Extrapolated values on a logarithmic scale. Open diamonds indicate extrapolation from demodulated pilot signals. Filled diamonds indicate extrapolation from analogue measurements. Symbols above the diagonal black line indicate sites where extrapolated measurements exceeded the predicted maximum values.

There is one site (Beaconsfield) for which the highest measured RF level exceeded the extrapolated maximum value. This indicates that there was a significant contribution from other base station antennas in the vicinity. At Beaconsfield there was only one service installed on this base station, but contributions for many other services were detected.

There are currently six surveyed base stations where the extrapolated maximum RF EME level exceeds the prediction from the environmental EME report. For four of these sites (Bulleen East, Maidstone, Palmerston and Lower Sandy Bay) the UMTS (or WCDMA) pilot signals were not demodulated and at Shepparton the LTE signals were not demodulated. In each of these cases the extrapolation was done assuming that only the pilot signal was present, i.e. it was assumed that there was no traffic present on the network at the time of the measurement. This conservative assumption leads to inflated values of the maximum possible levels of RF. The largest of these discrepancies was found at Palmerston where the extrapolated measured value was more than twice the prediction. The sixth site (Drummoyne) is the only one for which the extrapolation from demodulated pilot signals exceeded the EME report prediction, albeit only marginally. This difference (1.18% extrapolated compared to 1.13% of the limit) is well within the error bounds on the measurement.