From your list of items making up the system, antenna, co-ax and 2 TV's, you did not mention a splitter.

If this is a passive splitter, leave it in place (a 2-way splitter has min. 4 dB loss), if it is active amplified splitter, the gain of these is not enough normally.

An antenna pre-amp has 20 to 26 dB of gain, is mounted within 3 feet of antenna and has power supply indoors. If you use it with a passive splitter, the power inserter HAS to be after the splitter on the antenna side of the co-ax feed, NOT between splitter and TV's.

Google for amps, Wintronic has some and so do others, make sure it has both VHF & UHF rf gain, otherwise you will loss chn 9.

Basic system layouts from outside to inside.

Good high gain antenna, short co-ax (max 3 ft) to mast mounted pre-amp, good co-ax run to indoors (not more than 60 ft), add power inserter for pre-amp, add short co-ax to passive 2-way splitter, then short co-ax run to the 2 TV's.

Try to avoid amplified splitters for anything less than 3 tv's. More than that a very good cable amp/splitter with overall 0 dB loss should be used.

Good luck