Antenna hook up

If you are using an indoor Antenna:
1- the most probable reason would be the location of the antenna and TV in an area where the reception is very low. Indoors all houses are affected by the running electrical circuits which in turn generate magnetic field that together with the structure of the house obstruct or weaken the wave signals of wireless and TV reception. Also this issue may be aggravated by the vicinity you are live in. Where you are living may not have the optimum reception from some services including TV signals. Your best bet is to try moving the (Indoor) antenna closer to the outside (such as windows, or better to a balcony) and try all four directions of the house.
2- One other possibility, is the antenna jack being disconnected from one of its wires (or a de-solder) at an internal part of its circuit). This problem can be detected by trying another antenna that is working good when used with another TV (and preferably at a different location) thus testing for the possible weak signal at the same time.
3- The last possible issue is the antenna receptacle built onto the Tv set. This may have a problem of some element of it disconnected internally on the board or de-soldered..
If the Antenna is external, all the above points are still valid, but the probability is higher, for some hidden disconnection on the receptacle, the antenna plug or at the connection of the co-axial cable with the external antenna. (Once I found a co-axial cable with disconnections of its central copper wire within the protective insulating coat- probably due to defects in the plastic coat that had microscopic holes that allowed air and humidity into the central wire and caused it to corrode and have those discontinuities)..