Consumer Electronics » TVs » Why must satellite tv dishes be aligned so they....?

Why must satellite tv dishes be aligned so they....?

Explain why satellite TV dishes must be aligned carefully so they always point to the same position above the equator?

Ive had a crack at this question but cant get there...

So that they point at the satellite sending the signal from space.

Triangulation and constant stasis are the key. Satellite dishes need satellites to remain in a constant position so there is no interruption or waver in the signal. The also need to be at the equator which allows a constant stream of contact between the satellites.

That's where the satellite is located.

The dish must receive the satellite signal from way out in outer space; if it is pointed in the wrong direction the satellite signal will find its way to the dish.

satellites were located around an imaginary orbit in parallel the equator and distance about 36000 km. they are turning like the earth. so we see them stationary....geosynchronous...
in fact the dish looks at an arc....maximum elevation is on the south.....if we are on northern hemisphere...

higher gain antenna has sharper receiving angle... the gain of 1meter dish is about 40 dB (on 12 Ghz)...so it has narrower receiving angle.
http://www.marinesatellitesystems.com/us...
so it must be adjusted finely ...a small displacement of the dish reduces the received signal power.
http://www.satlinker.de/media/antennapat...
the maximum receiving point is on the top ... on both sides the receiving power becomes half (assume the satellite is on the top and the dish turns to the left...the right line reaches top..it will receive half of previous power) ...this pattern is rather wide ..imagine if it was narrower..the half-power angle would be very small.
pardon my poor english.

So that they point at the satellite sending the signal from space.

That's where the satellite is in relation to the planet.

If the dish isn't aimed properly, you get no signal, and that is worthless.


[The vast majority of the programming you can get is worthless, too,
but that's not the nature of this question...]

They must point to where the info is coming from, the sender, it's like pointing WiFi in one direction and standing behind it.

Because the satellites are in geosynchronous orbit about 22,500 miles up. They appear to be standing still. They are orbiting the Earth but at the same speed as the Earth is rotating Your satellite antenna has to be aligned so that it is pointing directly at the satellite you are receiving

The satellite is hundreds of miles away in space, so a few degrees turns into being miles off.