Fall 2004 Issue

Homing In

T-hunters Help the Public . . . and Fellow Hams

An unmodulated carrier had been jamming marine VHF Channel 12 for three days when Troy Waters e-mailed for help on the morning of April 28. His company, Jacobson Pilot Service, operates the pilot boats that guide tankers, barges, and other large vessels into and out of Long Beach (California) Harbor. The jamming was making his primary radio channel unavailable, causing confusion and consternation among the pilots and sea captains.

Troy had Googled “radio direction finding” (RDF) on the web, finding my site1 and the Southern California T-Hunters site.2 After reading about our mobile T-hunt adventures, he e-mailed to our reflector, “How would you like to participate in a waterborne T-hunt? We have a pilot boat that we could put you on and would be most grateful if you thought that you could locate the source of this transmission.”

When Troy’s e-mail arrived, I had already gone to work. Mailing-list moderator Steve Heinemann, N6XFC, got it and immediately called Troy. Then he called Mike Obermeier, K6SNE, and Dave Balgie, N6MJN. “I got them all in contact and left it up to them to track it down,” Steve told me.

K6SNE picks up the story: “Jacobson had asked the Coast Guard for a bearing but was told that its marine direction finders only work on Channel 16, the emergency frequency. Then Jacobson asked the Marine Exchange at Ft. MacArthur for a bearing ‘cut,’ as they called it. It went from the Exchange right through the banana warehouse at Long Beach Harbor and out to sea.”

“I was on the way to work at about 10:45 AM when Steve got me,” Mike continued. “I fired up the Doppler set in my truck, which was all I had for RDF on the marine band (see photo). I had no problem getting a bearing from Santa Ana. It took less than a half hour to follow my bearings about 20 miles down to Long Beach Harbor.”

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Mike Obermeier, K6SNE, gestures to explain how he just installed a new mount for his rotating 2-meter Yagi RDF antenna. His well-equipped truck also has a Doppler set linked to a GPS-based computer navigation system that he used to help locate a stuck marine transmitter at Long Beach Harbor. (Photo by the author)