Marian Rogan has been on the case for the past year and is regular contact with each of the commercial broadcasters regarding the problem which is due to a phenomenon called ‘atmospheric ducting’.

“Southern Cross Ten has come to Tenterfield a few times to check the tower and reception, but this was carried out during the day when reception is working fine,” Mrs Rogan said.

The Australian Communications and Media Authority (ACMA) advised that the Tenterfield broadcasting tower receives its commercial TV input signals off-air from the Richmond/Tweed (Mt Nardie) broadcasting tower. These input signals are intermittently interfered by signals from Darling Downs and sometimes Upper Namoi due to ‘atmospheric ducting’, causing reception problems in the area. (The input signals for ABC and SBS services are provided via satellite and are not affected by ducting.)

 “The ACMA is not across any specific timeframe for fixing this problem, but it is expected that in the first instance, broadcasters would try to improve their off-air receiving antenna system at the Tenterfield site to minimise the impact from the interfering signals,” an ACMA spokesperson told the Star.

“If improving the reliability of the off-air feeds does not work, broadcasters would need to consider more substantial and cosily infrastructure upgrades to provide input signals to the Tenterfield broadcasting tower by establishing microwave data connection links to the site.”

It’s the sporadic nature of the interference which is making it difficult to counteract, according to NBN TV’s broadcast engineering and technology manager Stephen Brown.

“All commercial broadcasters are aware of the problems at Tenterfield,” he said.

“In 2014 the government undertook a program to remove a portion of the top of the UHF broadcast band to assign to mobile communications. This was called the government restack program.

“Some transmission sites had to change their frequencies and move out of the top portion of the band. This has led to a compression of the UHF frequencies available to broadcasters and in some cases unfortunately situations similar to what is occurring in Tenterfield.

“Now the channels that are used to provide input signals to the transmitters at Tenterfield are the same as a high powered transmission site at Mt Mowbullan in the Darling Downs, some 250kms away. When the weather conditions are conducive the signals from the Darling Downs travel further and interfere with the input signals at the Tenterfield transmission site. This results in the transmitter outages we have all been seeing. “

Mr Brown said the weather conditions for this interference are mainly confined to the hot dry summer months, with the colder, wetter months less likely to have the interference produced. Mrs Rogan confirms that the loss of signal usually occurs in the morning and evening as the temperature changes rapidly, and she was still getting outages last weekend.

“The commercial broadcasters have been looking at different solutions for providing a stable input signal to the Tenterfield site,” Mr Brown said.

“We have already tried some different methods of signal input with varying results. We are all still looking for a more permanent, stable solution.

“We are all acutely aware of the problems in the area. NBN has remote monitoring of our transmissions in the area and can tell when we are having problems. We don’t like being off-air anywhere.

“We had to wait until an event occurred, and then look for what might be causing the problem. As this was weather-related it was happening at random times and the window of opportunity for measurement was not always optimal.

“Sometimes the interference would affect one broadcaster more than another. Also we had to co-ordinate investigations with the broadcasters at the site in Queensland as part of the investigative process involved turning off transmissions to see if the problem was resolved.”

Mr Brown said Southern Cross TEN, the ‘site controller’, has also been looking at the problem and examining all the possible scenarios for fixing it, and that broadcasters are working towards a solution before next summer’s bad season.

That can’t come soon enough for Mrs Rogan, who finds the situation very frustrating.

“If a service is available, it should be of good quality,” she said.