US Navy MARK 481 Radar Signal Simulator Trak Microwave Naval Air Systems Command. The perfect compliment to your Mark 481 Test Set!! Guaranteed to be working perfectly. Listing created with eLister 3.1.2 for Macintosh. From Black Magik Software. The item “US Navy MARK 481 Radar Signal Simulator Trak Microwave Naval Air Systems Command” is in sale since Tuesday, March 25, 2014. This item is in the category “Collectibles\Transportation\Boats & Ships\Military\Other Naval Collectibles”. The seller is “srlsales” and is located in Petaluma, California. This item can be shipped worldwide.