I was on the Thruway today and I got a J alert for the first time in over a month that I've had it (and I've done a lot of city driving). I was getting the Trooper's radar since he had someone pulled over and then all of a sudden, a sound I never heard before. I looked at it and there was a J on it.
It might have went to two bogeys, so maybe the person who he pulled over had a Cobra? Who knows, but I wasn't happy. Then the J alert silenced everything and then 15 seconds later or so, when I passed the cop, the V1 alerted again and to the rear (right after the J went away).