The example of WFBC and WTPT isn't relevant here: those stations were both licensed before 1964 and are grandfathered under a completely different set of spacing rules from the ones that apply to newer stations like 94.5 and 96.7.
I haven't looked at the spacings precisely, but it's a complicated thing: there are restrictions as to how close the Moapa/Bunkerville stations can be to their second-adjacent Vegas neighbors, which operate from two different sites: 94.1 and 96.3 are on Black Mountain, if memory serves, while 97.1 is on the more distant Mount Potosi. Then there are the requirements that each signal put 70 dBu over its own city of license. There are some other spacing issues to take into account - 94.5, for instance, has a first-adjacent to protect down in the Lake Havasu area. And there's the booster issue: to make a booster system work correctly, you want to have a calculated 60 dBu contour that covers as much of the target market as possible, but you want to put your "main" transmitter at a site that actually doesn't put much signal into the target market, preventing interference between the main and the booster.
It's not an easy thing to do well, even for the experts, and it can be a very expensive thing to get wrong. (Just ask anyone in San Diego watching the KSIQ follies...)
I haven't looked at the spacings precisely, but it's a complicated thing: there are restrictions as to how close the Moapa/Bunkerville stations can be to their second-adjacent Vegas neighbors, which operate from two different sites: 94.1 and 96.3 are on Black Mountain, if memory serves, while 97.1 is on the more distant Mount Potosi. Then there are the requirements that each signal put 70 dBu over its own city of license. There are some other spacing issues to take into account - 94.5, for instance, has a first-adjacent to protect down in the Lake Havasu area. And there's the booster issue: to make a booster system work correctly, you want to have a calculated 60 dBu contour that covers as much of the target market as possible, but you want to put your "main" transmitter at a site that actually doesn't put much signal into the target market, preventing interference between the main and the booster.
It's not an easy thing to do well, even for the experts, and it can be a very expensive thing to get wrong. (Just ask anyone in San Diego watching the KSIQ follies...)