Yes, please read what the people at www.radartest.com have to say about radar jammers here.

    "Except for the Phantom, which contains rudimentary radar-detection circuitry, each is essentially an empty box with a 12-volt power cord, a cheap cast-plastic waveguide assembly, one or two front-mounted LEDs, a basic power-supply circuit and a button or two. Press the button and an LED lights up, accompanied by a tinny bird whistle. ("Our patented 'FM Chirp', " company salesmen proudly proclaim.) We've tested these products a dozen times against every front-line police radar gun and laser, finding all of them utterly worthless."
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Tony Fabris