The description "Racon" beside an illustration on a chart would mean a __________.

The term "Racon" refers to a radar transponder beacon, which is designed to provide navigational assistance. When a vessel's radar system interrogates a Racon, the beacon responds by sending back a signal that is uniquely identifiable. This allows the radar display to show the position of the Racon along with a characteristic symbol, often assisting in identifying dangers such as rocks, safe navigation routes, or entry points to harbors.

The key function of a Racon is to enhance radar visibility and situational awareness for mariners. This feature is particularly useful in poor visibility conditions or in coastal areas where it can help in accurate navigation and positioning. Understanding its role in electronic navigation is essential for any sailor or navigator, as it can help reduce the risk of accidents and improve route planning.

The incorrect choices do not accurately describe what a Racon is or its function. A radar calibration beacon, for example, serves a different purpose related to the testing and calibration of radar equipment rather than providing navigational signals. A radar conspicuous beacon might be too vague, lacking the specific transponder capability that characterizes a Racon. Finally, a circular radio beacon suggests a different type of navigational aid that does not involve radar transponder technology.