Yes the antenna mast that is in place now can be used. The HD7698P/CPA-19 , should provide enough signal to supply signals to , 1 , 2 , 3 , 4 , Tv's using only the splitter that is required for the number of Tv's. If one Tv then no splitter , If 2 Tv's then a 2 way splitter , If 3 Tv's then a 3 way splitter , If 4 Tv's then a 4 way splitter. If more then 4 Tv's then install a Channel Master CM 3418 distribution amplifier in place of the splitters.
http://www.channelmasterstore.com. Channel Master also has digital converters that convert the digital signal to a analog signal for older analog tv's and the newest converter has 2 digital tuners a DVR and All Manner of inputs and outputs.