mikehar
Senior Member
I am currently exploring new radars and haven't given much thought to the claims made by Garmin and Furuno regarding their products. I have a straightforward question. If I understand the formula for calculating visual range on a spherical surface (even though the Earth isn’t perfectly round, it's acceptable for our purposes), an observer at a height of 40 feet can see a 40-foot tall object approximately 13 nautical miles away. Beyond that distance, it’s beyond the horizon. How is it possible for radars to claim a range of 72 nautical miles?