Originally Posted by difool2

The top-mounted detector will only show up after Dec 44, and only if you use the Late War Sensors Mod. There was a recent query about making it available earlier (can't find thread) but after some people (incl. me) tried to mod it to do so and couldn't we hit an impasse.

[Edit] Found it:

http://www.subsim.com/radioroom/showthread.php?t=114176