Satellite TV Technology Guide For Dummies

Television delivered by the means of communications satellite is called Satellite TV. A satellite dish and set-top receiver box is needed on ground to receive the signal. A wide range of services and channels are offered by Satellite TV.

A transmitting antenna located at an up-link facility forms the basis of satellite television. Huge satellite dishes, as much as 9 to 12 meters (30 to 40 feet) in diameter are used for uplink. More accurate aiming and improved signal strength at the satellite are the main benefits of such large dishes. The uplink dish is aimed at a specific satellite. The uplink signals are sent within a specific frequency spectrum, so as to be received by one of the transponders tuned to that frequency spectrum aboard the satellite. To avoid interference with the up-link signal, the transponder retransmits the signals back to Earth but in a different frequency band. The resending typically happens in the C-band (4–8 GHz) or Ku-band (12–18 GHz) or sometimes both. The portion of the signal course from the satellite to the receiving Earth station is called the downlink.

After traveling the great distance to Earth, the downlinked satellite signal becomes quite feeble. A parabolic receiving dish gathers the feeble signal and converges it to the dish’s focal point. Affixed on brackets at the dish’s focal point is a device called a feedhorn. The signals at or near the focal point are gathered by this feedhorn which is basically the flared front-end of a portion of waveguide and then sends them to a pickup connected to a low-noise block downconverter or LNB. The block of frequencies in which the satellite TV signals are transmitted is filtered and amplified by the LNB. The chunk of frequencies is then translated to a lower frequency spectrum in the L-band spectrum by the LNB. Direct broadcast satellite dishes are fitted with an LNBF which integrates the feedhorn with the LNB.

The satellite receiver set-top box then demodulates and translates the signals to the desired form of output for TV, audio, data, etc. The receiver is called an integrated receiver/decoder if the receiver includes the ability to unscramble or decrypt. The cable connecting the receiver to the LNBF or LNB must be of the low loss type RG-6, quad shield RG-6 or RG-11, etc. It cannot be standard RG-59.

The fact that satellite TV providers (like Dish Network or DirecTv) don’t have to lay miles upon miles of cable to deliver television programs to you is the main advantage of satellite TV. Equipment duplication is avoided since broadcast centers are not needed in every city. Since no re-laying of cable to up-grade services is required, satellite television is less expensive to maintain and up-grade and this saves you money. If the primary uplink center has a problem, the secondary uplink center automatically takes over broadcasting. That’s why satellite television has a less than 1% outage rate. Satellite television companies rate significantly higher in customer satisfaction than cable TV companies.