With a Off-Air Antenna you can receive locally broadcast television signals for free.
The primary object is to receive the big 5: ABC, NBC, CBC, PBS and Fox.
In most markets, these will be the highest powered signals comming from the transmission towers. In adition to the Big 5, many markets now have upwards of 50 channels available, all for FREE. These may include channels like ION, METV, MY 11, The CW, Create, Decades, and many Christion channels and shopping networks.