Dish Network HDTV DVR Satellite Receiver User Manual page 106

Chapter 12
Scanning for Over-the-Air Channels
About Over-the-Air TV Broadcasts
Over-the-air TV signals are broadcast by local TV stations from a transmitter tower. You
receive over-the-air TV signals using an indoor or outdoor antenna instead of the satellite
reflector. You are likely familiar with analog over-the-air TV signals—these are the signals
that have been used to broadcast TV for many years. New digital over-the-air TV signals
are broadcast and received in the same way. Digital over-the-air TV broadcasting uses
advanced technology like that of the DISH to deliver superb picture quality and CD quality
sound. However, digital over-the-air signal reception (like analog over-the-air signal
reception) depends on several things.
• The distance between the broadcast station and your home (the farther away the
station, the weaker the signal)
• The broadcast station's power (the lower the power, the weaker the signal)
• Obstacles between the station and your home, such as mountains, buildings, trees, or
other objects (these may block or reflect the signal before it reaches you)
• Multiple broadcast stations (to receive good signals from several stations, you may
need to compromise in how you aim the antenna or you may need more than one
antenna)
The effects of poor digital reception are different from the effects of poor analog reception:
• Poor analog reception usually causes the TV picture to be "snowy" or to include
"ghosts", that is, multiple images caused by receiving reflected signals along with the
direct signal from a station. Poor digital reception may cause the TV picture to be
"pixelized", that is, broken up into small squares of various colors, or to be lost
completely (the TV screen is all black or all blue).
• Digital broadcasts often provide either a very good picture or no picture at all.
• You may be able to receive a poor analog signal but not be able to receive a digital
signal at all.
To get the best possible digital signal reception, make sure you use the best over-the-air
antenna for where you live:
• You can receive a limited number of channels using a rabbit ears type antenna on top
of the TV set, or a much larger number via a large UHF/VHF indoor/outdoor antenna.
• The higher the quality of the antenna you use, the greater its range and the better its
reception will be.
Digital OTA Broadcasts are Still Developing
• Broadcasters may still be testing digital signals and their strength and may stop
broadcasting without notice, vary power output, or turn it off.
• Some broadcasters do not yet have permanent transmitter tower.
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