Amateur television is the transmission of Broadcast quality video and audio over the wide range of frequencies of allocated for Radio amateur use. ATV is used for non-commercial experimentation, pleasure and public service events...
(ATV) operator that transmits (broadcasts) content over terrestrial television
Terrestrial television is a mode of television broadcasting which does not involve satellite transmission or cables — typically using radio waves through transmitting and receiving antennas or television antenna aerials...
. A television transmission can be by analog television
Analog television is the analog transmission that involves the broadcasting of encoded analog audio and analog video signal: one in which the message conveyed by the broadcast signal is a function of deliberate variations in the amplitude and/or frequency of the signal...
signals or, more recently, by digital television
Digital television is the transmission of audio and video by digital signals, in contrast to the analog signals used by analog TV...
. Broadcast television systems standards are set by the government, and these vary around the world. Television stations broadcasting over an anolog system were typically limited to one television channel
A television channel is a physical or virtual channel over which a television station or television network is distributed. For example, in North America, "channel 2" refers to the broadcast or cable band of 54 to 60 MHz, with carrier frequencies of 55.25 MHz for NTSC analog video and...
, but digital television enables them to broadcast subchannels.