On the 15th March 1999, a group of amateur radio operators set out to find the source of a signal that had jammed the VK3RSE repeater for several hours. Adam, VK3HDF and myself found the source of the interference with a foxhunting sniffer at about 10:15PM. We were then joined by Jack VK3WWW and Steve VK3TSW and at about 10:30PM decided to knock on the door of the house concerned.

      The interference was caused by a pair of Sennheiser model RS6 cordless headphones located more than ½ km from the repeater site. This device had three channels of operation on 433.4, 434.13 and 434.5MHz. Although the owner of this device had selected the 434.5MHz channel, the device was transmitting well under this frequency and was emitting quite a healthy signal slightly below 434.375MHz. The modulation was wide enough to reset the repeater periodically and that is the reason it never timed out. The owner of the headphones was quite apologetic and had absolutely no idea that the device was causing so much interference. This was the first time he had used them. He had been watching a movie for the previous 3 hours which had just finished when we knocked on the door.

This time we were lucky. He could have just as easily told us to go jump. Then what? We could complain to the ACA, but it would probably take them weeks to get around to doing something about it, if they did anything about it at all!

Bryan, VK3YNG.