The ACMA plays an important role in managing the radiofrequency spectrum. For most people, this means making sure radiocommunications services- such as your mobile phone or television- work without being affected by interference. Some of this work is done behind a desk, but quite a lot takes our inspectors on the road to all parts of Australia-from our major cities to coastal and outback communities. They respond to complaints of interference and work hard to make sure that everyone gets the most out of Australia's radiofrequency spectrum.
Take Melbourne as an example. On any given day, staff could be looking for a stolen EPIRB (that's short for an emergency position-indicating radio beacon), fixing interference to the mobile phone network near Flemington Racecourse or finding and shutting down unlicensed radiocommunications services.
Resolving mobile interference at the Spring Racing Carnival
With the activated EPIRB found and removed, the ACMA inspector was ready to move on to his next task-fixing interference to Telstra's mobile network near Flemington Racecourse.
Telstra had told the ACMA that one of its base stations near Flemington was experiencing interference from an unknown device. The inspector travelled to Flemington to find the source and stop the interference.
The information he had to work with pointed to an unknown device located in a housing area close to the racecourse. He scoured the area using a spectrum analyser to gauge the device's signal strength and find its location. The high-density housing complicated the search because it caused high signal reflections but drawing on his expertise the inspector soon narrowed the search down to a couple of houses.
He then used his 800-900 MHz directional Yagi antenna to pinpoint the exact location of the device on the second floor of a townhouse, near an external wall. With the cooperation of the resident the inspector quickly identified a malfunctioning indoor TV antenna booster as the source of the interference. This type of device should not transmit radio signals in the mobile phone band (pictured below).
The inspector clearly explained to the resident why the device couldn't be used and advised on how television reception in the townhouse could be improved. The device was disconnected by the inspector and an advice notice issued to reinforce the information he had provided.
With the booster out of action, Telstra's mobile network was restored to its normal performance.
Drive-by monitoring-identifying and stopping unlicensed radcomms services
The inspector's final task of the day came to light during routine monitoring of the radiocommunications spectrum. While ACMA inspectors are travelling around, they normally have a spectrum analyser running in the vehicle. This picks up any unusual radiocommunications activity. In the Melbourne suburb of East Brunswick, the analyser identified interference in the 1920-1930 MHz frequency range-the frequency used for mobile phone services in Australia.
Stopping his vehicle, the inspector used his 1900-2100 MHz directional Yagi antenna and spectrum analyser to determine the direction of the signal. He soon narrowed it down to a nearby commercial multistorey building and tracked the signal to a first-floor business.
After introducing himself and explaining the reason for his visit, the inspector searched for the source of the interference. Again, the Yagi antenna and spectrum analyser came in play, zeroing in on the interfering signal and identify the device as a wireless VoIP server. The server was part of the business's telecommunications setup and, while other pieces of their phone equipment were appropriately labelled with the A-Tick compliance mark, this device was not and was being operated without a licence.
The device's operation was also not licensed under the applicable spectrum licence or the Cordless Communications Class Licence, which would generally authorise devices of this kind. However, in this case, this licence did not apply because of the device's operating frequencies.
The device was disconnected and a non-compliance sticker attached, so that it could not be used again. The inspector clearly explained why the device could not be used in Australia and issued a warning notice for the unlicensed operation of a radiocommunications device.
With this interference resolved, this day in the life of the ACMA inspector came to an end.
Under Australian law, ACMA technical standards must be met before telecommunications customer equipment is connected to the phone network. Among other things, these standards cover the personal health and safety of users and maintaining the integrity of telecommunications networks.