Radar Overload?

Early last week, my brother Chip and I happily saw our 31-foot Ocean Master Expeditor, get dunked for the season. We're always happy to see her out of shrink wrap on in her slip. We decided to give her a good cleaning and wax the topsides. When we got down to the boat, Chip started tooling around with the electronics he'd just re-installed after making some modifications to the electronics box. Well, he turned on the Northstar 6100i plotter-radar and after a few minutes we saw the picture you see here with spoke-like lines shooting out.

Baffled by what we saw, we inquired with Northsar about the image as we'd never seen it before. Well, we got the answer (see below):

"The odd spoking you're seeing is caused by interference of another nearby radar. Or, If you have another radar on your boat—you should use Interference rejection = HI. It will go away. Interference is circular like this on the longer ranges. You also have the GAIN up quite high on the longer ranges....too much "speckle". Very common to see this spoking in a marina..."

We're happy to report everything is back to normal. If you see a similar problem this season, rest assured it's not major and easily corrected.