If the HD7084P does not do the complete job of reception , I think it will. Then use the 91XG with a Antennas Direct CPA-19 preamp aimed at about 94 degree magnetic compass as a dedicated antenna for the reception of only WLIW-DT (UHF Tv Channel 21) PBS. Contact ,
http://www.tinlee.com for a UHF 21 band pass filter that allows UHF channel 21 to pass and rejects all other channels. Separate coax wiring will be used for 91XG antenna system and HD7084P antenna system. The two antenna systems will not be connected together on to one coax. The two separate antenna systems coaxes will go to the location/s of the tv or tv's. A Radio Shack #15-1968 remote control A/B antenna switch will be at location of the tv/s , the separate coaxes will connect to the inputs of the A/B switch and output of the A/B switch will connect to the tv. That means a separate splitter and coax wiring. Or if it is only one tv for the WLIW option then run the one coax of the 91XG preamp antenna system to the one tv and use a A/B switch at the one tv.