There are a few different types of antennas for TV reception depending on your signal area and distance from transmitters you may need different stuff

Used for indoor antennas, boats and AM reception. Dipole (Rabbit Ears) These antennas are non directional! These antennas are not very sensitive generally come with built in amplifiers. They easily pick up reflected signals giving rise to ghosted images in analog and if it is bad enough will cause pixilation and sound chirps with digital. NOT RECOMENDED FOR DIGITAL

These Antennas pick up is related to the number and size of its elements It tends to have more gain in a restricted range of frequencies, It is less likely to receive lower frequencies from power line interference, car ignitions and high powered radio transmitters. This is because only the dipole is connected to the down lead.Yagi Antennas:

Digital Log Periodic
This antenna has less gain but can maintain it over a wide range of frequencies. The gain is related to the range of frequencies and the number of dipoles. Typically Log Periodic TV antennas designed for bands 3-5 cover this range as a complete coverage from 174 to 820 MHz giving rise to its triangular or “Christmas Tree” shape. Since there is no TV channels between the top of channel 12 (10) and the bottom of channel 28 (SBS) this sensitivity is wasted on being sensitive to two way radio communications operating within this band.

This type of antenna has better vertical directivity than all the others and it is typically used for long distance reception and signal paths blocked by terrain and buildings. Reflected ghosted signals are usually not a problem in these weak signals areas
Phased Arrays: