A recent case of a very low level of interference was affecting the maritime VHF distress and calling channel 16 at the Maritime New Zealand’s Wairarapa and Picton sites.
The investigation into the interference took seven days to locate and resolve and involved contacting ships and shore stations on the Wairarapa coast, as well as both ground and helicopter searches. However, no interference was detected in the Wairarapa area.
Eventually a very low level signal was detected, and direction finding indicated it was from a broadcast transmission site 120km from the affected Wairarapa site and 185km from the Picton site.
A visit to the broadcast transmission site was arranged and the low level interference source was traced to a high power television transmitter. The cause of the interference was an open inspection panel which had been left open for maintenance purposes.