I haven't had much luck pulling far away FM stations, but MAKG is sure correct about AM---I used to get lucky and pick up KFI AM640 broadcast of Phil Hendrie in LA when I lived in Logan UT....a 770 mile difference.
Nothing lucky about it. KFI is a Class A, formerly known as a "clear channel", protected station serving up 50,000 watts on a channel protected for thousands of miles from any other station being licensed on their frequency.
http://en.m.wikipedia.org/wiki/Clear-channel_station
(Not to be confused with Clear Channel Communications, Inc., the company that owns many of them.)
They're *supposed* to be heard many states away, by engineering and licensing design. The history of the clear channel stations in AM broadcast was that they could receive each other from one coast to the other, this allowing for a network of stations that could pass news, time synchronization, etc...all the way across the Continental U.S. without need for land-based links.
Our local clear channel is KOA at 850 KHz. Their claim that they're heard in 38 states, Canada, and Mexico at night, is legitimate. Not that they have any night programming since Rick Barber retired. He passed away last year from complications due to ALS.
http://www.denverpost.com/ci_23562669/rick-barber-overnight-denver-radio-fixture-30-years
Clear Channel Communications downsized Rick in 2012 to replace him with Coast to Coast AM with George Noore, who has never been an adequate replacement for Art Bell.
In my car, I average about 70 or so miles before I start to lose the signal.
My record, however, is 1000 miles!
Oh forgot to add that it was via a string of FM repeater sites....
Heh. Out here that kind of distance only takes three linked repeater sites.
Multiple clubs have been joining together with the encouragement and original build-out of one particular club here, to build a very large scale microwave data backbone. Many of the pesky analog FM links are being dumped for a shared IP backbone that already stretches from Wyoming to
nearly New Mexico along the eastern slope of the Rockies, and is making headway pushing west into the rocks.
Lead engineering on that system started at Rocky Mtn Ham Radio (
www.rmham.org) who operates it as their backbone for a massive DMR digital radio system, as well as extending DMR-MARC, and the Colorado Connection (
www.colcon.org) and Colorado Repeater Assn (
www.w0cra.org) are now assisting with sites, personnel, and general good-will to extend the backbone and ride along for some of both system's audio links via VoIP, which removes some really tough analog shots that barely made it to hub linking repeaters.
Still plenty of analog links, but they're on their way out.