Field Operations staff regularly face new challenges and experiences as they travel across Australia to resolve interference issues. A recent expedition to Thursday Island is a good example of the range and diversity of work in the Field Operations Section.
This particular trip involved travel by Plane, Car, Ferry, and Helicopter all in response to a request from Optus to investigate interference to their newly commissioned 3G mobile phone cell on Thursday Island, Qld.
Trips of this nature require a lot of planning and preparation including travel arrangements, but most importantly ensuring the right people are available to help resolve the interference. In this case, it was important that a Senior Optus Network Engineer accompanied the ACMA Field officer to the island to help investigate and resolve the source of the interference.
Flights were arranged to Cairns, then to Horn Island and finally the local ferry to Thursday Island. Once on the island they attended the site, and confirmed by connecting their test equipment to the base transceiver station, that the cell was experiencing interference from an unknown source. This information allowed the team to determine the direction and characteristics of the source of the interference and they set about locating this interfering signal.
After driving around the island the test equipment confirmed an interfering signal was being transmitted from Hammond Island to the immediate north of Thursday Island. Local technicians provided the team with a possible source of the interference. It was thought a company that provided maritime services, with engineering support in the Torres Strait, was using radio links that operated on Hammond Island and other islands and outposts providing the connection for tidal and current measuring equipment. This equipment is used by the maritime industry for all shipping accessing the Queensland coastal ports. Further enquiries confirmed the brand and hardware of these radio links, and the capability of operation outside the correct frequency range for the Australian Spectrum.
During the conversation with this company it was discovered that they could not access the radio links for remote maintenance as the equipment had developed a communications error. This left only one option, to travel to Hammond Island with the local technician and restore the equipment and complete the testing. The local technician organised for a helicopter to depart Horn Island Airport, land on the helipad at Sadies Beach and transport us to and from the site on top of Hammond Island.
Once on Hammond Island, testing began and it was confirmed that these radiocommunications links were the source of the interfering signal.
A warning notice was issued and the company rectified their radiocommunications equipment resulting in the radio links operating in the correct frequency range and the Optus interference to their 3G cell been resolved.
The issue of interference by radiocommunications equipment designed for other countries but operated within Australia continues to be a challenge for Field Operations and the ACMA.
The helicopter onsite (Hammond Island) with a view back to Thursday Island