An indirect radar echo is caused by a reflection of the main lobe of the radar beam off the observer's vessel. Which of the following is NOT a characteristic of indirect echoes?

Correct Answer: Option B — They always appear on a bearing of 90° from the true bearing of the contact.

Indirect echoes are caused by reflections off the ship's own structure, such as masts or stacks. They do not have a fixed angular relationship to the true target bearing. Their appearance is erratic and depends entirely on the geometry of the reflecting structure, making option B a false characteristic.