How do satellites send imges to earth?

Answer 1

Satellites transmit signals using highly directional electromagnetic waves.

Electromagnetic waves are used all the time in today's technology; microwaves use microwaves which are the same as mobile phones, televisions use ultrahigh frequency waves, visible light is in fact electromagnetic waves.....

Where our mobile phones use multi-directional antenna satellites use parabolic dishes to produce unidirectional signals which are transmitted to receiver stations on the earth. A sky box is an example of one such receiver where only a download link can be established, i.e you cannot use your set top box to control the satellite.

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In Addition (added by another user)

Microwaves are used because their wavelength is long and thin, they don't refract much making them accurate. Furthermore, radio waves cannot be used as when under 30 MHz they reflect of the ionosphere and if they are above, their wavelength makes them refract too much. Strong signal strengths are needed as when above 30 GHz things like rain, dust etc reduce signal strength.

Hope this helped.

Answer 2

Ok, there are 4 main pieces of equipment needed for satellite communications. The dish, aka antenna, is composed of the reflector and the feed horn. The reflector is the dish and the feed horn is the portion of the arm directed at the dish. The other parts are called the BUC, LNB and the modem and I will go over each piece individually. This may be a little lengthy but I will describe the signal flow in the end.

The word modem is actually an abbreviation for Modulator/Demodulator. This is the technial term for taking the information going to and from the computer or tv or whatever, and converting it from binary which is the universal computer language (ex. 00101100) to a radio frequency, ex. 70MHz. It is also programed with the transmit and receive frequencies.

The BUC, or Block Up Converter, is part of the uplink side. Uplink meaning from earth to satellite. The BUC puts the 70MHz signal on a "carrier" frequency which is an SHF (super high frequency) signal. SHF is the frequency range in which satellites operate on (3GHz to 30GHz).

The LNB, or Low Noise Block converter, is part of the downlink side (satellite to earth). Since the antenna receives all the frequencies its satellite is transmitting, you need a filter. The LNB only lets through the block of frequencies you need.

So here's the signal flow starting from earth. I'll use a satellite internet system as the example starting from the computer. Information is passed through an ethernet cable to a router, then to the MODEM. The MODEM then transfers the its signal to the BUC. From the BUC it goes into the FEED HORN which shoots the signal at the REFLECTOR, which in bounces off of towards the satellite. From the satellite, signal comes back down, bounces off the REFLECTOR and is absorbed by the FEED HORN. It then goes through the LNB, back to the MODEM where that block of frequencies is filtered down to the one frequency you need and converts it back to binary(0010110). From the MODEM it goes back through the router to your computer.

This is just one type of a satellite system. If you would like to know others like TV, satellite radio, or military communications you can ask me specifics. I went through 8 months of training in the army and I am taking college classes in the communciation field. I am currently in Iraq maintaining satellite communications and obviously have nothing better to do a lot of the time. Also, if you have any questions about the army I can answer those too. Some questions you may have about military topics I will not be able to answer due to security issues, but most of them I will.

Answer 3

Pretty much the same way you send an email with a picture, or post a photo to Facebook.
The picture is translated into a set of data, and the data is sent wherever it needs to go,
through whatever kind of pipe exists to take it there. From a satellite to the Earth, the
only kind of pipe available is radio.

Answer 4

I'm pretty sure that they take pictures through the satellite specially built for that. Then it puts it in film

Answer 5

They will usually use radio waves for communication.

Answer 6

they reflect the signals

Answer 7

They do so using radio waves.