4/23/25, 7:35 AM Satellite broadcast TV, DTH TV & Digital Terrestrial TV
1. DIGITAL TERRESTRIAL TRANSMISSION (DTT)
DTT is the backbone of free-to-air access and the most widely used means of receiving
television globally.
Terrestrial television or over-the-air television (OTA) is a type
of television broadcasting in which the signal transmission occurs via radio waves from
the terrestrial (Earth-based) transmitter of a TV station to a TV receiver having
an antenna.
The term terrestrial is more common in Europe and Latin America, while in Canada and
the United States it is called over-the-air or simply broadcast.
This type of TV broadcast is distinguished from newer technologies, such as satellite
television (direct broadcast satellite or DBS television) in which the signal is transmitted
to the receiver from an overhead satellite; cable television, in which the signal is carried
to the receiver through a cable; and Internet Protocol television, in which the signal is
received over an Internet stream or on a network utilizing the Internet Protocol.
Terrestrial television stations broadcast on television channels with frequencies between
about 52 and 600 MHz in the VHF and UHF bands.
Since radio waves in these bands travel by line of sight, reception is generally limited by
the visual horizon to distances of 64–97 kilometers (40–60 mi), although under better
conditions and with tropospheric ducting, signals can sometimes be received hundreds of
kilometers distant.
DTT signals are received and distributed to viewers by standalone antenna and/or in-
building communal aerial broadcast distribution system as illustrated below.
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, 4/23/25, 7:35 AM Satellite broadcast TV, DTH TV & Digital Terrestrial TV
2. SATELLITE COMMUNICATION FOR TELEVISION
Terrestrial broadcast of television programmes required VHF and UHF bands. However,
these bands could not use the ionosphere, and their propagation was based on line of sight,
which limited the range to about 100 km with high towers for antenna.
For long distance communication, there should be a system which could be launched out
in space to stay at high altitudes of several thousand kilometers.
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1. DIGITAL TERRESTRIAL TRANSMISSION (DTT)
DTT is the backbone of free-to-air access and the most widely used means of receiving
television globally.
Terrestrial television or over-the-air television (OTA) is a type
of television broadcasting in which the signal transmission occurs via radio waves from
the terrestrial (Earth-based) transmitter of a TV station to a TV receiver having
an antenna.
The term terrestrial is more common in Europe and Latin America, while in Canada and
the United States it is called over-the-air or simply broadcast.
This type of TV broadcast is distinguished from newer technologies, such as satellite
television (direct broadcast satellite or DBS television) in which the signal is transmitted
to the receiver from an overhead satellite; cable television, in which the signal is carried
to the receiver through a cable; and Internet Protocol television, in which the signal is
received over an Internet stream or on a network utilizing the Internet Protocol.
Terrestrial television stations broadcast on television channels with frequencies between
about 52 and 600 MHz in the VHF and UHF bands.
Since radio waves in these bands travel by line of sight, reception is generally limited by
the visual horizon to distances of 64–97 kilometers (40–60 mi), although under better
conditions and with tropospheric ducting, signals can sometimes be received hundreds of
kilometers distant.
DTT signals are received and distributed to viewers by standalone antenna and/or in-
building communal aerial broadcast distribution system as illustrated below.
about:blank 1/10
, 4/23/25, 7:35 AM Satellite broadcast TV, DTH TV & Digital Terrestrial TV
2. SATELLITE COMMUNICATION FOR TELEVISION
Terrestrial broadcast of television programmes required VHF and UHF bands. However,
these bands could not use the ionosphere, and their propagation was based on line of sight,
which limited the range to about 100 km with high towers for antenna.
For long distance communication, there should be a system which could be launched out
in space to stay at high altitudes of several thousand kilometers.
about:blank 2/10
