The best way to Maximize signal strength is a bigger antenna. I recommend a Winegard HD7696P antenna for reception of the Phoenix stations at South Mountain. . To receive the Phoenix stations from South Mountain and Tucson stations from Mount Bigelow also , Like KGUN 9 and etc. , I recommend a Winegard HD7698P antenna. The antenna aim for the Phoenix and Tucson stations is 117 degree magnetic compass. Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html. Some signal fluctuations of weaker stations like the ones at Tucson at 123 miles away is normal. 123 miles is a long way for a Tv signal to travel , not very many places in the USA that have that length of transmission and reception. Also the hoa can not tell you what size of antenna you install and use , here is the Federal Law that says Yes you can install and use any size of antenna.
http://www.fcc.gov/mb/facts/otard.html. . . A good place to put the splitter is some place out of the weather / away from direct rain fall. And a location that makes it easy to split 2 ways to the 2 Tv's. Where the cable company has the connection location is a good place , there should be a ground wire at that location to use. You can use the coax wiring that is in or on the house. However Do Not connect Tv Antenna to any active cable coax , Do Not connect to active cable Tv coax , Do Not connect to active cable internet coax , Do Not connect to active cable phone service coax , or any other type or kind of active cable delivered service.