This just came through from the MED Newsletter - shockingly boring news from December 24, 2004:
At 5:30pm on Friday 24th December, the RSM National Coordinator, who provides a 24/7 contact point for emergency services to advise of interference issues, passed a call from the Maritime Safety Authority’s Maritime Operations Centre (MOC) to Joe Den Exter in our Auckland office. Maritime VHF channel MM16 (the international distress channel) was being jammed at MOC’s Auckland and Bay of Plenty sites.
A call by Joe to the MOC determined that the noises overheard indicated a vessel with a jammed microphone was out at sea and underway, somewhere in the thousands of square kilometres of sea covered by those radio sites. While our Radio Inspectors sometimes achieve miracles, walking on water has never been one of them. Accordingly, Joe commenced the co-ordination process of calling on organisations that have the resources for water-bourne assistance; the Coastguard and the Police.
The Auckland Volunteer Coast Guard was able to determine that they could hear the problem on their Sky Tower receiver, but not on the local receiver at Mechanics Bay, indicating that the offending vessel was well out to sea. One of the Coast Guard’s vessels was able to hear the jamming transmission in the Whangaparaoa Peninsula area, but did not have direction-finding (DF) equipment to try and trace it. No Coast Guard vessels were available in the Auckland vicinity to pick up Joe so he could exercise his equipment and skills, so his next call was to the Police.
The Police Launch team at Mechanics Bay was available and do have DF equipment, so set out towards Whangaparaoa in search of the interference source. At this point Joe was making phone calls to the Maritime Operations Centre, the Coast Guard and the Police Launch to keep all parties up-dated. Unfortunately, before the Launch reached the vicinity of Whangaparaoa, and before they could pick up the jamming signal, they were called to an emergency at Waiheke Island.
By this time, the Coast Guard vessel that had originally been able to hear the interference had returned to their base at Stanmore Bay, and although on return they had initially been able to hear the problem on their base set, the signal disappeared a little later on. As the MOC were still getting the problem on the Auckland site, Joe continued to work with the Coast Guard, checking for reports from other vessels that could hear the problem. Although there was some indication that the signal could be heard (in different areas), no report was sufficiently firm to follow up at that point.
These various processes had taken the time through to 10pm and complete darkness. Locating a vessel at sea in darkness by chasing a faint radio signal is virtually impossible, so further action on the chase was postponed until daylight the following morning. Sometime between 4am and 5am Christmas morning, the offending signal had disappeared, so no further action was possible to identify the offender.
Next time you are out boating, spare a thought for care of your radiotelephone, and ensure that your microphone is put away properly in its holder, so that misplaced equipment cannot jam the transmit switch.