Alright after playing with the LA today on a road with heavy traffic, i've thought of another way to test the jammer.
I'm going to put one head on the 2003 Silver Honda Civic, set in the same spot as today and see if I can get a reading. My theory depending on how close you are to the car infront of you, the jammer may not work.
Ideas / thoughts on how to do this? Anything you want to see?