Here follows a true account that happenned last week tuesday, followed by how it was accomplished.
I was driving on the motorway, at a nice relaxed speed, when my zr4 started to scream. Because I was within the speed limit, I just hit the mute button.
About three or four hundred metres further, low and behold the motorway was blocked by a roadblock. I switched the jammer off imediatly. As I got close to the officers, the one tells me to pull over. When asked why I was pulled over he said it was because I was using a jammer at the speed trap.
I proceeded to tell him that I do indead have a jammer fitted but seeing as how it is broken it would be impossible for me to have jammed anything. He asked me to turn it on, it didn't. Asked me to start the car and turn it on, it didn't.
Said he was going to call the expert and then called a friend over. I showed them that indeed the jammer was plugged into power and all wires were plugged in but the jammer didn't work. He then said he would have to fine me for having the jammer on the car, whereupon I asked him to show me the law stating it was illegal to own a jammer. His last words to me were "I guess you right, you can go!"
So I started my car and as I drove away I switched the jammer on
How it was done.
I installed a switch from a house burglar alarm system (the one with a magnet) in my power line, and where my power line runs under a plastic panel, I stuck a magnet on the outside with prestick. As soon as I saw the roadblock, I put the magnet in my pocket and presto, the jammer wont turn on.
Hope this suggestion helps all of you too!