[seafarer]

SD Radar did not pick up aircraft radar signals. It was a long wavelength emitting radar that, like any radar, detected it's own signal being reflected off an aircraft. The only way the aircraft could know you were scanning it with SD radar was if the aircraft was equipped with a radar detection set.

The same thing for SJ radar - a ship would have to have a radar detection device onboard to know it was being scanned. While it became known after the war that a lot of IJN ships had radar detection systems (at least starting in 1942 onward), only a very few Japanese aircraft ever did, and most of those were 1944 or later.