What your scanner will receive, and from where, depends on a number of factors, most of which are mentioned above. As a rule, a handheld scanner with a standard "rubber duckie" antenna won't recieve much if you're more than a mile or so away from the source. There are many ways to increase your area of coverage though, like external antennae, pre-amps...Sometimes though, you'll get good results with a (relatively) cheap magmount antenna and a decent scanner. (I have a Uniden UBC92XLT with an airband tuned magmount antenna and I love it...picks up everything but aircraft on the ground from my home 22miles away from the airport). My magmount was about £20. (Or $29.52 - Thanks Google!).