Sunday, 20 May 2018

Audit finds low real-life exposures around base stations with high predicted levels

Bangay tower test

Michael Bangay demonstrates live EME readings on a 35m mobile phone tower


Measurements taken around 10 base stations with high predicted electromagnetic radiation levels have found exposures are on average seven times lower than those calculated in carrier reports.

The objective of the independent audit, funded by network carriers and conducted by radio frequency expert Michael Bangay, was to take real-life measurements in the locations predicted to have some of the highest exposures in Australia – predictions as high as eight per cent of the safety limits.
“There was a particular concern that the predicted levels were getting up and we needed to look at those sites to see what the actual levels were,” Bangay told the Science and Wireless 2013 conference.
“When I looked across all of the sites I find that the levels that I am actually measuring are around 0.5 per cent of radiation protection standard number three – whereas the average of the predicted levels is over 3.5 per cent.”
“These are the worst case estimates for sites around Australia.”
Under the industry code of practice all network carriers - when upgrading or installing a new base station - are required to produce a report that shows the predicted cumulative levels of exposure to radiofrequency electromagnetic energy (EME) around the new or upgraded facility.
ARPANSA says the calculations used in EME reports are deliberately conservative and are intended to show “maximum levels that can almost never be exceeded when the base station is operating.”
For example, the calculations assume that all planned transmitters are operating at maximum power, when in reality base stations adjust their output power based on the number of connected devices and automatically reduce their emissions to the lowest levels to make a quality connection.
The ARPANSA EME reports – publicly available on the new Mobile Site Safety website - provide the predicted maximum levels of exposure at varying distances up to 500 meters from a base station. They also predict a specific location around the site that is expected to be the highest for EME exposure.
Bangay comparison
[Source: Bangay presentation Science and Wireless 2013]
“The predicted values given in the ARPANSA EME reports are [on average] seven times above what we measure,” Bangay said.
“Therefore we can say the ARPANSA environmental prediction report provides a conservative estimate of EME levels around a base station.”
Measurements taken around a base station in Rosanna, Victoria, which had the highest predicted maximum EME level in the study of 8.35 per cent of the standard found the highest measured exposure level was actually 0.43 per cent of the safety standard.
The highest measured value from the ten base stations tested was 3.04 per cent of the standard taken at Hurstville in NSW, a site which had a predicted maximum of 6.4 per cent.
Bangay is an independent expert accredited by the National Association of Testing Authorities (NATA) and the tests were carried out following NATA procedures.
He is widely recognised as one of Australia’s leading professionals in EME measurements and RF safety with more than 32 years of experience at both ARPANSA and RadHaz Consulting.
In two new YouTube videos for Mobile Site Safety, Bangay demonstrates how live EME readings are taken from a crane in front of a 35m mobile phone tower and he also demonstrates the correct use of the RadMan personal RF monitor for people working on or near radio communications antennas.

Broadcast signals make up most environmental EME exposures

Bangay told the public forum that in most of his testing around Australia the majority of EME exposures that he measures actually come from television and radio broadcast signals.

“One of the realities of course, is that there are many radio wave signals out there in the background and so when we go out to do a measurement to look particularly at base stations we need to take in to account there are many other signals and exclude them,” Bangay said.
Mr Bangay showed measurements of all radio frequencies taken at a site in North Ringwood, Victoria about 300m from two mobile phone base stations and 400m from a Wi-Fi smart meter base station. The measurements showed exposures from FM radio signals – coming from antennas 12 km away - were the highest at that particular site and 66 per cent of the total EME came from TV and radio signals.
“Looking at the measurements taken at North Ringwood they come to an overall exposure level of 0.013% of Radiation Protection Standard number three.”
“And might I say that figure of 0.01% to 0.1% is about what I find around Brisbane, Sydney and Melbourne… depending where you are - mainly made up of broadcast sites.”
Bangay pie
[Source: Bangay presentation Science and Wireless 2013] 

Published 5/02/2014

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