[CapnScurvy]

Sounds like your sub is equipped with SJ Surface Radar.....since its working at the PPI or A-Scope screens.

I can tell you, using the stock game radar parameters is like trying to see through fog......you can't detect a thing most of the time.

As nionios pointed out, the two stock radar stations (either PPI or the A-Scope stations) are for SJ Surface Ship detection only (neither will pick up airplanes). The SD Air Search Radar isn't represented as a "station" but is simulated by you getting a message of "Airplane Spotted" and, showing a plane icon on the Navigation Map. There is no specific radar station for the Air Search capabilities. You just know its on board at the start of the war, and you rely on the message text to tell you when a plane is spotted.

With the stock game, surface ships may or may not be seen with the subs SJ surface radar, even if you can see the ship with the naked eye! The stock radar works about 30-40% of the time, with no way of figuring out how far away something detected is (truly, the American radar stations are just eye candy. The German Radar at least gives you a digital Range reading, although, it will only provide it in Meters....no matter which measurement unit you choose!). The stock surface radar doesn't even come close to picking up planes (even though the real life set could). You need to modify your game to have the SJ radar stations work as expected for both surface ships and air plane detection.