Friday 22nd January. An as-yet-unidentified radio transmission caused major headaches for operators of UHF radio equipment at Melbourne Park yesterday.
The interference at the Australian Tennis Open disrupted services in the 460 - 510 MHz bands, in addition to Digital Cellular coverage in the area.
According to an Australian Communications Authority source who wished to remain nameless, the noise was allegedly caused by a broadband microwave transmission related to the HSV7 telecast. The offending signal successfully eliminated the UHF communications of Melbourne and Olympic Parks, ambulance & medical services, Victoria Police, Telstra, and the Mobilenet Digital system.
The interference persisted from 1700 hours to approx. 1830 hours local time, and changing to other channels by affected services made little difference to the end performance.
On Friday 22nd January an ACA inspector arrived from Canberra and was escorted around the venue by HSV7 technical officers, "who were exceptionally co-operative," according to another technical source who was working at Melbourne Park at the time. Allegedly the ACA inspector had a complete list of ALL frequencies being used on-site, and a projection of all associated intermods and their interference potential.
"The ACA inspector could identify no real problem, as obviously [the interference] had stopped by the time he arrived," said the source. "Except for a couple of slightly spurious radio microphones… certainly nothing with the capacity to wipe out such a huge spectrum could be found."
Suspicion allegedly rests on three broadband feeds for a special HSV7 weather / sports broadcast, combined with link vans from GTV9 and ATV10. These may have created the freak interference which resulted in the demise of all nearby narrow-band UHF services for over 90 minutes.
It is believed that the ACA are also investigating large UHF system deployed by IBM, for game scoring on Centre Court. IBM reportedly has a temporary licence for 469.500 MHz amongst other frequencies, and all of the services affected on Thursday can be found in and around this area of the UHF band. It is alleged that this may have contributed to the intermod.