How to use APR-1
 

FOTRSU 1.7
Just had it fitted on my boat. How is it used? I assume it's a passive device, in which case how will I be alerted that it's picking up enemy radar?

With map contacts enabled, you should see a line as would sonar, except it will be at a much greater distance than sonar so easy to distinguish. In the dialogue box at top of screen, crew may report "Detecting Radar Signals", sometimes, they do, sometimes they do not.

Thank you.