When this happens, a good understanding of what you are seeing will go a long way toward identifying the real problem. Poor shielding in the coax or the TV itself are usually the culprits. Also, herringbone interference may be the result of an installer's injecting modulator signals that are too strong, or on channels too near other useable channels. Typically occurs when an antenna is located midway between two stations broadcasting on the same channel. The taller the tower and the more powerful the transmitter, the further a signal can be received for any given terrain.
Frequency also plays a role.
The higher the frequency, the more power is required to reach a given distance. Another interesting distinction about frequency is that the lower the frequency, the more apt a signal is to bend over hills and follow the terrain. Houses located over a hill may receive VHF channels very well, while UHF channels are weak. In this situation the UHF portion of the antenna should be improved either by getting a higher-gain antenna, raising the height, amplifying, or combinations of these. Ghosting is often caused from adjacent hills or buildings reflecting late, low-level signals into the side or rear of the receiving antenna.