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shyam arshid
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Join Date: Feb 2012
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Satellite Phone

02/04/2012 10:03 AM

How a satellite phone with such small battery can transmit signals to satellite which is many kilometers above the earth?
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lyn
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#1

Re: satellite phone

02/04/2012 10:07 AM

It's magic.

There's nothing between the small phone antenna and the large satellite antenna. Not even air, so a very small signal can go a very long way.

The battery has little to do with broadcast range.
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shyam arshid
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#2
In reply to #1

Re: satellite phone

02/04/2012 10:12 AM

Don't that signal get attenuated with the atmospheric layers present in between?
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Anonymous Hero
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#4
In reply to #2

Re: satellite phone

02/04/2012 10:23 AM

Yes, and the ionosphere is another barrier to contend with.

However, it really does not take too much power to punch through and you would be surprised how far 1 Watt can go.
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redfred
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#6
In reply to #2

Re: satellite phone

02/04/2012 10:36 AM

Yeah, it does. Most of the actual signal level loss is actually from the inverse square law but atmospheric effects happen, too. Consider the reverse. You cannot run power lines up to a satellite yet the the solar cells are able to produce enough electric power to transmit to hundreds of telephones on the surface simultaneously. There's been many improvements in low noise amplifiers and more efficient modulation techniques from the days of Telstar 1 but this is just a known problem to overcome.

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energyconversion
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#5
In reply to #1

Re: satellite phone

02/04/2012 10:33 AM

"Not even air," Really? I've got about 100 kM of air above me - that's where space "officially starts" I believe.
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Noudge79
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#3

Re: satellite phone

02/04/2012 10:22 AM

It's the other way around. Dont you think? Communication Satellites are powered in the way it could communicate the Earth effectively. It is not limited by how small the signal of your equipment is.

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shyam arshid
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#7
In reply to #3

Re: satellite phone

02/04/2012 10:42 AM

thanks to all.....

my doubt is clarified
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cnc jim
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#8

Re: Satellite Phone

02/05/2012 8:43 AM

Around here there are massive masts, this is as far as the phone signal needs to go. The mast takes it from there. (attracting pollutants as it does, but that is other threads)

cnc jim
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redfred
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#9
In reply to #8

Re: Satellite Phone

02/05/2012 9:14 AM

That massive antenna system is part of the ever popular cell phone network. A satellite phone uses a different network. The cell phone network has regions where the hand held phones cannot reach the network antennas. A satellite phone instead does transmit and receive directly to one or more satellites. These satellites are not in geostationary orbit, so the signal does not have to travel as far. To maintain coverage (most of the time) there must be multiple satellites orbiting the Earth in many orientations. Because there's this mesh of satellites in constant motion all around the Earth there are no places on the surface of the Earth where a satellite phone cannot get a service signal.

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cnc jim
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#10
In reply to #9

Re: Satellite Phone

02/05/2012 9:30 AM

Oh, thanks REDFRED

cnc
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Haajee
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#11

Re: Satellite Phone

02/05/2012 10:29 AM

Satellite phone

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cnc jim
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#12
In reply to #11

Re: Satellite Phone

02/05/2012 10:50 AM

Fascinating.

Thankyou UNCLE

cnc jim
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Larry Burns
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#13

Re: Satellite Phone

02/05/2012 9:41 PM

The satellite phone transmit to a loco tower the tower transmit to the satellite when someone 500 mi. away call you, the call goes to there loco tower then satellite then to your loco tower then your phone!!!
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redfred
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#14
In reply to #13

Re: Satellite Phone

02/05/2012 10:09 PM

No Larry, read the other comments and the Wiki link.

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Larry Burns
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#15
In reply to #14

Re: Satellite Phone

02/05/2012 10:41 PM

I think the tie your waring is choking you, but that is how communications work!!!
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Wal
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#16
In reply to #15

Re: Satellite Phone

02/05/2012 11:47 PM

Settle down Larry!!!!

Some communications systems rely on terrestrial repeaters, not all.

Please read the wikipedia link provided Hajee.

We are talking about directly communicating satellite (orbiting repeater) phones here.

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Users who posted comments:

Anonymous Hero (1); cnc jim (3); energyconversion (1); Haajee (1); Larry Burns (2); lyn (1); Noudge79 (1); redfred (3); shyam arshid (2); Wal (1)

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