Over The Air
There are a variety of ways to transmit television signals to consumers. Over The Air (OTA) signals are transmitted from terrestrial towers, instead of across copper or fiber optic cable or from satellites.
OTA signals may be analog, as in the case of standard NTSC, PAL, or SECAM broadcasting, or digital in the case of DTV and HDTV signals like ATSC or DVB-T. Depending on the type of TV (analog or digital) you have, it may be able to receive analog OTA broadcasts, digital OTA broadcasts or both. If you have an HDTV monitor (HDTV display with no tuner) you'll need to use an external tuner to receive either analog or digital OTA transmissions.