Question about TP and Spotbeams

[jbleser]

First off I am newbie (satellite enthusiast) and have learned ALOT off this site! However, I have not found much explaining about spotbeams.

Could someone explain to me the difference between spotbeams and transponders..

Thanks

 

[primestar31]

First off I am newbie (satellite enthusiast) and have learned ALOT off this site! However, I have not found much explaining about spotbeams.

Could someone explain to me the difference between spotbeams and transponders..

Thanks

This is a real simplified explanation, so here's my try:

Think of a transponder as a multiple channel radio transmitter. It broadcasts to all the people that can pick up it's signal, and that have the right equipment to receive it. That's over a bigger area.

Now, imagine if you will, that a SPOTBEAM is kind of like a flashlight beam of light, or laserbeam, that aims at a particular "tight focused" area. It carries a certain set of channels meant for that area alone, but still actually broadcasts from a transponder. So, if you aren't within the spotbeam area of where it's focused, (or real close by, with a much larger satellite dish for more signal)you will NOT receive the signal that the spotbeam sends out.

So, if you live in Chicago say, and want channels that are on a New York spotbeam, it ain't going to happen, unless you move to New York. BUT, if you live in say Mid-Michigan, and want channels that are broadcast on a CHICAGO spotbeam, that might be doable with a larger dish, because the spotbeam overlaps (splashes) a bit.

 

[BuddyBoy]

Think of a spot beam as a transponder that, rather than illuminate all of the continental United States, focuses its beam at an area about the size of half of California. This allows the same transponder frequency to be reused at multiple locations in the USA, sending different local stations into different geographical areas. Without the spot beam, it would require more transponder frequencies to send the same number of local channels, as there would be no re-use of the transponder frequencies. With a spot beam, transponder 12's frequency can carry say, five different sets of local channels into five different geographic areas, thus conserving a limited resource (transponder frequencies).

 

[jbleser]

primestar31 & BuddyBoy -

Thanks for the explanation!

 

[Smith P.]

Check this also:
[ame="http://en.wikipedia.org/wiki/Spot_beam"]Spot beam - Wikipedia, the free encyclopedia[/ame]
Transponder (Satellite communications - Wikipedia, the free encyclopedia)