Coastal Skipper and Yachtmaster Quiz · Safety and communications
A straight line of 12 evenly spaced dots has appeared on your radar. What is it, and where is the thing that is making it?
A radar screen with your heading at the top and three range rings, 4 miles apart. On the port bow a straight line of 12 evenly spaced dots runs outwards from inside the innermost ring to beyond the second ring, in line with the centre.
Show the answer
A search and rescue transponder (SART): it is at, or just short of, the dot nearest to you. A SART is carried in liferafts and answers a 9 GHz (X band) radar with a line of 12 dots running outwards from its own position, so the survivors are at the dot nearest to you, or a little short of it. The dots are about 0.64 miles apart. As you close to about a mile the dots widen into arcs and then rings. A racon paints a Morse letter, not evenly spaced dots.
