The reception is frequently very pixilated and therefore unwatchable. That also affects any recordings.

If you are only using a TV antenna, then the air signal that you are receiving is not sufficiently strong enough to present a full data frame to your receiver. If you are on cable, then your cable company is not sending a strong enough signal. This could be the Cable company's fault, or your cable connection could be at fault. In that case call your cable company and complain.

If it is over the air, then you will have to put up a better antenna, and perhaps an enhanced antenna with a db gain that will give the signal a boost such as http://www.target.com/GE-Indoor-Outdoor-TV-Antenna/dp/B0026SSAOM

When the FCC mandated that the US TV signals switch to digital, then the frequency was upped to a higher level. Those higher level frequencies have a disadvantage in that they are affected by line of sight interference from trees, houses, other structures, in that they bounce off. Also weather interferes with the signal. There is a move afoot to increase the strength of the signal, but that is years away.