Scott Fybush said:
The Las Vegas FM stations on Mount Potosi, 8600 feet above sea level (88.9 KNPR, 92.3 KOMP, 93.1 KPLV, 97.1 KXPT, 104.3 KCYE, 107.5 KXTE) have tremendous reach up and down I-15 in both directions. It's not uncommon to hear them clearly beyond Barstow, 120 miles or so to the south, and north to the Arizona border, more than 100 miles away - and it's pretty amazing to hear the Potosi FMs keep coming in loud and clear going south on I-15 while the terrain rips the Black Mountain FMs (94.1, 95.5, 96.3, 98.5, 100.5, 101.9, 103.5, 106.5) to shreds before you even hit the California border.
Scott, you can actually start picking up certain Las Vegas FMs along I-15 on Black Ridge between Cedar City and St. George, UT. Although St. George is in a valley, KXTE always came in okay in the area. I used to listen to Howard Stern on whatever it was called in the 90s (was it KFBI?) around that area. Never strong, but you could listen to it in the car around much of the city; particularly the north end. They all die through the Virgin River Canyon, but it's all Las Vegas FMs when you pop out to the east of Littlefield, AZ. So, Vegas FMs really get out there.
Another set of FMs that do amazingly well are the class Cs from Salt Lake City. They actually pop in through the San Rafael Swell along I-70 in central UT (about 170 mi from their tx sites) and around Richfield and Cove Fort, UT. They're in and out, but they make the trip (not counting the translators, either).
The class A signal at 98.3 from Price (KARB) also comes in well along I-70 and that's a good 50 miles with 7 kw at -104' AAT. Some translators from Price also make it that far, but only when you have very favorable terrain. That area is gorgeous with sandstone canyons and a stop at the Eagle Canyon viewpoint will result in a fine view and an FM dial filled with signals - all of which are from more than 50 miles away (Price, Richfield, Moab, Green River, Salt Lake City and even Grand Junction, CO)!
The Salt Lake FMs also make their way east to about Little America, WY; north beyond Malad, ID and west out to near Wells, NV without help. More than 120 miles in every direction thanks to being perched up on the Oquirrh Mountains at about 9000' above sea level. Not too shabby.