It would help tremendously if you posted the make/model of the set.
Years ago some sets had separate RF connectors for antenna and cable, nowadays they just have a single connector for both. If you still have the owner's manual for the set it might clear up your problem. If not, you can go to the set's mfg's website and download the manual.
It is a hitachi l20a980a
That is the model. We cannot figure out how to connect the cable to it.
What country are you in? Here is what it says that this set has:
Video System: PAL, SECAM, NTSC3.58, NTSC4.43, PAL60, N-PAL, M-PAL
HDTV Compatibility: Yes
TV Scan Lines: 480i/p, 576i/p, 720p(50/60), 1080i (50/60)
TV Tuner: NTSC-M SECAM B, G / D, K / K1 PAL B, G, H / I / D, K
CableCARD Slot: No http://www.bhphotovideo.com/c/produc...ti_System.html