Combining several antennas for TV.

I wish to combine two (or more) roof antennas, each pointed at different stations/cities.  I bought a Radio Shack 15-1234 2-Way Hybrid Coax Splitter (75-Ohm) and fastened the two RG6 coax's to the two ports maked "set 1" and "set 2", with a coax leading to my TV attached to "input".  It is my understanding that the "Hybrid" splitter is susposed to be able to work in that manner.  In sum, it did not work...no signal to the TV.

What am I doing wrong?