[The Deuce]

There was an old car and driver article about this question. They got a hold of a Jammer (totally illegal to sell) that you actually built and installed yourself. The transmission was strong enough to violtae FCC guidelines and the transmittor would melt itself after about 15 seconds. So it was instant on with a detector. I wish I could rember who sold the kit, as the pieces themselves were ok (like the prohibition days of selling moonshine kits). Can someone recall the test, or brand? I may have to dig through 5-6 years of the mag to find it, but I plan on getting one for my Cobra, but don't have the car yet.
Banshee and Mr. 5.0 both make good points. I think I drive more like Banshee though, and I've been ticketless for almost 7 years, knock on wood.