单项选择题 （）is not a job of the radar antenna.

单项选择题 You are using a radar in which your own ship is shown at the center，and the heading flash always points to 0°. If bearings are measured in relation to the flash，what type of bearings are produced? （）

单项选择题 You are underway in thick fog. You have not determined if risk of collision exists. Which statement is TRUE?（）.