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While studying radio electronics I stumbled across a small article about wave interference on the same frequency. The article was very simple explaining that if there a stronger emitter on the frequency or the emitter is closer than any other - it will take over the frequency.

That got me interested, but I couldn't find any information of how it works from the inside:

  • How does the wave gets overriden?
  • How can one emitter be stronger than another if there, for example are equal distance from the receiver and from each other?

I am especially interested in following topics:

  • How can I amplify a radio signal?
  • Is it harder to amplify signals on higher frequencies, e.g. WI-FI Internet?
  • What is the basic principle of devices that creates noise and blocks certain frequencies?
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    \$\begingroup\$ Too many questions in one question. Ask the 1st by itself. Google will handle most of the others, have a look and then come back and ask specific individual questions. || The 1st answer depends on the type of signalling system. Some systems can lock to a specific signal. But for eg AM broadcast band radio stronger signals tend to dominate over weaker signals. | You make it sound like you are assuming several things which YOU know that YOU know are not actually true. eg Why would you expect all signals to be the same strength at its source ? You can make very low or very high power signals. ... \$\endgroup\$ – Russell McMahon Feb 22 '15 at 6:18
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    \$\begingroup\$ .... Do you really think that a radio station and a cellphone have the same signal strength. | Do you really think that the very large transmitting aerial on broadcast station have no more effect than the aerial on a hand held phone? | Presumably (and hopefully) "No!" in both cases. \$\endgroup\$ – Russell McMahon Feb 22 '15 at 6:19
  • \$\begingroup\$ Thank you for the commentary. The reason I asked the questions was because I'm new to electronics and I don't know. Also it's hard to google for these things because I don't always know where to start. I would like to get an answer that could satisfy my curiosity on a level of a high-school project in a class room - make a simple emitter with a magnet and battery or something :) There are multiple questions - but they are connected. \$\endgroup\$ – Creative Magic Feb 22 '15 at 6:33
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    \$\begingroup\$ (1) I suspect that you could answer the questions re aerial size and power of traansmitter OK. (2) The site discourages multiple questions per question unless they are rather more tightly limked than yours are. (3) Here we go :-) - If you search on "RF amplifier" and use eg Google image search you may find the result useful. Each image is a related page. Enjoy. \$\endgroup\$ – Russell McMahon Feb 22 '15 at 9:57
  • \$\begingroup\$ "Difficulty of amplification" is harder to do easily. A: Yes. As frequency rises amplifying devices get more expensive and harder to make. But because a lot of experience has been gained frequencies that were once very hard and expensive are now MUCH cheaper and easier by experience. eg 2.4 Ghz WiFi band was once the province of advanced researchers but now ' every home has one'. \$\endgroup\$ – Russell McMahon Feb 22 '15 at 10:02
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How does the wave get overridden? Minor edits of Grammar

This happens in the same manner as two people singing the same tone, such as the note C. As one or maybe two individuals are listening for this tone, they acknowledge it an try to listen. The time when waves are overridden is simply when one person speaks louder than another and then the listener/tuner cannot hear one person because the other is speaking too loudly. The same goes with waves of electronic schematics. When one wave is more amplified than another at the same frequency, the more powerful wave will drown the other out. This is to make the idea of waves getting overridden simpler to understand and this actually validly answers it because it deals with waves.

How can one emitter be stronger than another if there, for example are equal distance from the receiver and from each other?

answering how to amplify signal in a circuit

This is possible for many reasons. One, the antenna can have different amplification properties.Two there could as such thing as an Omp-Amplifier IC or Chip (same thing but different names) that can be used to amplify the signal. You can amplify a signal with an antenna or an IC that has amplification qualities. Less resistance in a circuit is also helpful in amplifying the current which could also amplify the signal. Any of these are good in this process of amplification

Is it harder to amplify signals on higher frequencies, e.g. WI-FI Internet?

No! All you need is a 2.4GHz antenna, such as a ceramic or actual WI-FI specific antenna. It is not any harder than using any other antenna, just make sure the hookup is compatible to the one you are using. Very simply, all you need is a WI-FI antenna, end of story. The only thing you would choose is the data rates, but that is irrelevant. http://www.tp-link.us/article/?faqid=3 This is where the link of a better explanation is

What is the basic principle of devices that creates noise and blocks certain frequencies?

Describes the way waves work in radios This explains how they send and receive frequencies, specifically speaking they oscillate at certain frequencies and then put the message overtones on top of this, so what the receiving is trained to vibrate at the same way as the receiver is only that frequency. It is constantly moving at that frequency, and that one only. So when a signal comes in with a message, it demodulates that frequency to find the overtone and then either play it or turn it into a digital message.

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  • \$\begingroup\$ Hey I am sorry I will edit in the future when I have time but that should be enough. In the edit I will probably list some diagrams and GIFs on the wave patterns. I will also cite some the sources for future research \$\endgroup\$ – Jdude2345 Feb 25 '15 at 1:27
  • \$\begingroup\$ That's a great answer and I will be happy if you can improve it even further. Please feel free to add as many details as you feel will be helpful. \$\endgroup\$ – Creative Magic Feb 25 '15 at 2:01
  • \$\begingroup\$ Yeah just give me until this upcoming weekend \$\endgroup\$ – Jdude2345 Feb 26 '15 at 1:15
  • \$\begingroup\$ nice answer. very helpfull. \$\endgroup\$ – Denis Mar 22 '15 at 2:08
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How does the wave gets overriden?

In AM radio, this is mostly a matter of perception. Imagine one person shouting in your ear and another person whispering on the other side of the room. Mostly you'd hear the shouting person. You could say they had "overridden" the quieter speaker.

In FM, the modulation scheme actually does tend to favor receiving a stronger signal and reduces the effect of interfering signals. This is a reason for the higher fidelity of FM radio.

How can one emitter be stronger than another if there, for example are equal distance from the receiver and from each other?

They could be broadcasting with different power levels. All else being equal, a 100 kW station will produce a stronger signal than a 1 kW station if the receiver is equidistant from them.

They could be broadcasting with different antenna radiation patterns. Radio broadcasters will use antennas that transmit preferentially in certain directions in order to deliver their signal to more populated areas. If you are in the favored direction from one station but in an un-favored direction from the other transmitter, you could receive a stronger signal from the first one.

There could also be terrain effects or other impairments reducing the signal received from one station or the other, even if their source power is equal.

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  • \$\begingroup\$ Would you care to edit the answer providing more detailed information? I think this answer could get the bounty if improved. \$\endgroup\$ – Creative Magic Feb 28 '15 at 7:28
  • \$\begingroup\$ Can you remove the last 3 bullet points from your question? They're basically totally separate from the main question based on the post title and would require a full textbook to answer. \$\endgroup\$ – The Photon Feb 28 '15 at 16:43
  • \$\begingroup\$ No, the last three points are important to me. If the full answer is too long, I'd sure love to see links that would explain the topics in full length. \$\endgroup\$ – Creative Magic Mar 2 '15 at 1:09
  • \$\begingroup\$ If the last three points are important, you can one or two more questions to cover them. \$\endgroup\$ – The Photon Mar 2 '15 at 1:37
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From my experience:

Leaky feeder is used for "amplifying" radio signals underground.

In general, radio signal attenuate over distance that also means power is lost over distance.

Bandwidth and distance also opposing each other.

Circuit is amplified using opamp or diferential amp or etc.

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