Invest in an escort PASSPORT 8500 series or higher and you will not be let down. Me and a buddy were coming back from Dayton on 70 and detected this cop a mile and a half away through fog that i couldn't see a foot in front of me. We were all looking around trying to find him lol. There are a lot more stories related to it as well but thats just one. Most time they don't work in fog but this one does. I'm buying one as soon as i get the money, you can pick up an 8500 for around 150 on eBay.