F a transmiter for arguments sake, fitted in a satalite orbiting the earth

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In summary: Just that they would cancel at that particular point and then continue on.In summary, the conversation discusses the potential for two identical signals, transmitted from separate locations with a 180 degree phase difference, to cancel each other out at a point of meeting. The experts agree that while this is possible in theory, the odds of it actually occurring are extremely low due to the vast distances involved. They also mention that interference can occur in all types of waves, including light and sound. The conversation also briefly touches on the Hadley-Twiss-Brown Effect, which states that two light sources located a small distance apart can produce a combined light that is in phase. However, this is a quantum mechanical effect and not directly related to the original question
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wolram
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im not sure how to pose this question, my ist try.
if a transmiter for arguments sake, fitted in a satalite orbiting the Earth sent a 1mgh sgnal say for 10 secs and an identicle transmiter some distance away transmited an identicle signal but 180 deg phase difference would they cancel each other at point of meeting, if ansewer is yes then is this true for all waves ?
please exuse non formalities.
 
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  • #2


Originally posted by wolram
im not sure how to pose this question, my ist try.
if a transmiter for arguments sake, fitted in a satalite orbiting the Earth sent a 1mgh sgnal say for 10 secs and an identicle transmiter some distance away transmited an identicle signal but 180 deg phase difference would they cancel each other at point of meeting, if ansewer is yes then is this true for all waves ?
please exuse non formalities.
No, each would continue on, independent of the other.
 
  • #3


Originally posted by Labguy
No, each would continue on, independent of the other.
Why not? Light waves are certainly capable of interfering with each other. I think they WOULD cancel each other out.

And yes, interference works for all waves. Light, sound waves, waves on the ocean, waves on a string, etc.
 
  • #4


Originally posted by russ_watters
Why not? Light waves are certainly capable of interfering with each other. I think they WOULD cancel each other out.

And yes, interference works for all waves. Light, sound waves, waves on the ocean, waves on a string, etc.
The odds of photons (or any EMR) transmitted miles away from each other actually interacting is "astronomically" small. Imagine how our radios would sound if they did. Also, the "folded" optical paths in some telescope designs would see what? Black?
 
  • #5
please elaborate labguy russ
 
  • #6
Originally posted by wolram
please elaborate labguy russ
My "elaboration" is easy. There would be no "point of meeting", and the odds of photon interaction would be virtually nil.
 
  • #7
now i see distance is major factor, in a confined space there could be interferance but how far away from each other would trasmiters have to be to guarantee no interferance? transmiters rated at 100W.
 
  • #8


Originally posted by Labguy
The odds of photons (or any EMR) transmitted miles away from each other actually interacting is "astronomically" small. Imagine how our radios would sound if they did. Also, the "folded" optical paths in some telescope designs would see what? Black?
It was a hypothetical, Labguy. Of course the possibility is small. Maybe a better hypothetical would be using a laser. That way you have a LOT of photons traveling in the same direction. Shine another laser in the same direction out of phase and they WOULD cancel out.

now i see distance is major factor, in a confined space there could be interferance but how far away from each other would trasmiters have to be to guarantee no interferance? transmiters rated at 100W.
Distance isn't really much of an issue. The issue is can you make the beams cross out of phase? Its a piece of cake with sound, since the wavelengths are pretty long, but its tough for light since the wavelenghts are very small.
 
  • #9
Isn't this idea the basis for the GPS system? You recive signals from 3 separate satilites, compare the phases and determine your postion.

Yes, the signals would interfer but, each signal would continue uneffected after the point or points of interference. At any point is space where the phase of the signals differ by 180deg there will be distructive interference, at points where the signals are in phase the signals will reinforce each other.
 
  • #10
There is something rather similar

I read in the Feynman lectures, but I couldn't find it in the index. I believe it's called the Hadley_Twiss_Brown Effect (delightfully British name) that says that if two light sources are located a small angular distance apart at the receiver, even though they may be far apart in space, the example used a street lamp and a star, the combined light will tend to be in phase. It's strictly a quantum mechanical effect due to the fact that photons are bosons.
 
  • #11
off to the Physics forum this goes!
 
  • #12
so, if 2 laserbeams one 180 degrees out of phase with the other are focused at a point one wave lengh in front of a perfect reflector, would there be no reflected light?
 
  • #13
Originally posted by Integral
Isn't this idea the basis for the GPS system? You recive signals from 3 separate satilites, compare the phases and determine your postion.

Yes, the signals would interfer but, each signal would continue uneffected after the point or points of interference. At any point is space where the phase of the signals differ by 180deg there will be distructive interference, at points where the signals are in phase the signals will reinforce each other.
I don't think GPS uses actual interference patterns, but instead compares coded signals. Similar, but not quite the same.

And your second part is correct. I didn't mean to apply that the waves would cancel and then cease to exist.
 

1. What is the purpose of a transmiter fitted in a satellite orbiting the earth?

A transmitter fitted in a satellite orbiting the earth is used to send and receive data and communication signals between the satellite and the ground station. This allows for real-time communication and data transfer between different locations on earth.

2. How does a transmiter in a satellite work?

A transmitter in a satellite works by converting electronic signals into radio waves, which are then transmitted to the ground station. The ground station then receives the signals and decodes them into usable data or communication. The satellite's orbit also plays a crucial role in ensuring proper transmission and coverage.

3. What are the advantages of using a transmiter in a satellite for communication?

There are several advantages to using a transmitter in a satellite for communication, including: wider coverage compared to ground-based communication, less susceptibility to interference, ability to transmit signals to remote or inaccessible locations, and real-time communication.

4. Can a single transmiter in a satellite handle multiple functions?

Yes, a single transmitter in a satellite can handle multiple functions, such as data transfer, communication, and navigation. This is made possible by using different frequencies and channels for each function.

5. What factors affect the efficiency of a transmiter in a satellite?

The efficiency of a transmitter in a satellite can be affected by various factors, including the satellite's orbit, the transmitter's power and frequency, atmospheric conditions, and the receiver's quality. Interference from other devices or signals can also impact the efficiency of the transmitter.

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