Satellite Dish
A satellite dish is a
device that is used to obtain a signal from a satellite
and send it to a receiver that will decode the signal
for use by a TV display unit.
The dish consists
of:
-
Low Noise Block (LNB): The device on the front of
a satellite dish that receives the very low level
microwave signal from the satellite. It then changes
the signals to a lower frequency band, amplifies them
and sends them down the cable to the indoor
receiver.
-
Feedhorn
(LNBF): This is a horn antenna used to convey radio
waves between the receiver and the reflector.
-
Reflector:
The area that collects the signal and bounces it to
the LNB.
Direct broadcast
satellite dishes (DBS) use an LNBF which integrates the
feedhorn with the LNB. Modern dishes intended for home
television use are generally 43 cm (18 in) to 80 cm (31
in) in diameter and are fixed in one position for
Ku-band and the new DirecTV Ka-band reception.
A common
misconception is that the LNBF (low-noise
block/feedhorn), the device at the front
of the dish,
receives the signal directly from the atmosphere instead
of being beamed to the dish, which because of it's shape
will collect the signal into a smaller area and deliver
it to the
LNBF. |
