Difference between Satellite? Terrestrial Link??

[jigisha]

Hello ..
Can any one explain me,
what is the difference between Satellite Link and Terrestrial Link ?
How then fundamentally differ?

Thank You.

 

[deepmak]

Hello Jigisha
usually a terrestrial link rely on broadcasting tower(s) (in TV case ) to emit their channels info to end users who receive them via antennas mounted on roof of on TV set , this broadcasting require line of site between transmitter and receiver , thus the distance between the tower and antenna is kinda limited , the range can be extended via adding multiple towers in different locations , in data link , usually cables connect the transmitter link to end user
satellite link rely on broadcasting information ( mixed load of data ) to a satellite that in turn re-broadcasting the info in a wide area , thus giving much more coverage area , since the satellite is orbiting earth. however , internet satellite link suffers more delay or lags due to the long travel distance the data packages have to travel.
Regards

 

[chuckey]

The aiming accuracy of the transmitting aerials for a satellite requires a very order of accuracy, as the satellite is like a terrestrial receiver , only 22,000 miles away and not 30 (and its moving about in its licensed position)!!
Frank

 

[crutschow]

One fundamental difference is the frequency of the RF carrier. Terrestrial TV uses frequencies below 1GHz. Digital Satellite TV uses frequencies above 10GHz.

 

[dick_freebird]

Satellite links have the vertical atmospheric attenuation
only for the extent in that direction (modulated by cloud
cover or lack, etc.). Point to point terrestrial links traverse
a greated atmosphere-attenuated path. Of course the
hop distance is well less than geosynchronous orbit.
The choice of frequency band includes the absorbtion
vs divergence calculation, among other things.

Satellite transmit power is limited to what battery-
averaged solar input can support, on the down leg.
Terrestrial (other than very remote link stations)
can afford wire-line power to the limits of emitted
power levels.

Satellites do not face competition from fiber optic
links, unlike terrestrial backhaul and trunk systems.
Their cost structure is high, with launch costs and
the use of specialty products specially qualified and
unserviceable-in-the-field. The whole "ecosystem"
favors one-to-many broadcast covering regions that
do not have good, or have overpriced wire-line or
FO service (terrestrial to-the-home service is very
anti-competitive, other than phone vs cable choice,
but you get only one of each) or cross-continent,
cross-ocean sorts of leased channels. At some point
the expensive hop beats the even more expensive
(or impractical for reasons of NIMBY / eminent domain
type stuff) laying of new cable.

Point to point microwave / millimeter wave vs P-t-P
free space optical is another competition, each has
some band-specific sensitivities to precipitation, fog
and baseline atmospheric attenuation; the optical
can also be refracted away from target by thermals
and to on.

Not all links use geosynchronous birds - the one-to-
all, tend to because homeowner dishes would be less
affordable and less reliable if they required active
pointing (either gimbaled or active array - Joe Allthumbs
isn't going up on the roof for quarterly maintenance
of the mechanicals, and phased array receiver antennas
use a lot of semiconductor content, more reliable but
way more spendy). So LEO birds tend to be used for
handset apps where proximity fixes the power problem
and most calls don't outlast the time-overhead slot or
can be handed off to the next bird flying over, without
too much concern for continually re-pointing.