Well, I finally found myself the culprit!
I move the indoor antenna to outdoor and found that the TV can't receive any signals, then I figured it probably it's the cable.
I traced the cable around the house and found that the cable is cut almost in half behind the bushes because I just trimmed the bushes 3 days ago.
I trimmed the bushes vertically and the trimmer cut right into the coaxial cable! How stupid I am! It's my fault that I did not fasten the cable using nails/steel staples around the house since the wall/ground is concrete.
Now I know how to fix it, thanks for all the help.
The signals all came back after I cut the cable and attached a new RG6 connector. Fixed. Edited by mxnerd - 10/6/13 at 4:34pm