Resonance

[KrisBlueNZ]

This thread makes me think of Chopin's Minute Waltz. He was inspired to write it when he saw a dog chasing its tail.

Electro132, it would really help if you EXPLAIN WHAT YOU WANT TO DO.
Not the technical details of what you think you want, but the OVERALL AIM OF YOUR PROJECT. Include lots of background information, and references to any Internet-accessible material that relates to what you want to do.

 

[Harald Kapp]

Obviously it seems to you that electromagnetic radiation is all the same regardless of frequency (as can be seen from your naive requirement for a 0...3000MHz range).
That is not the case.
The character of electromagnetic radiation changes remarkably with frequency.
At very low frequencies you need super big antennas. You are rewarded with electromagnetic waves that can penetrate deep into and through solid or liquid material. This is used e.g. for VLF (very low frequency) communication from and to submarines (sorry for the military aspect here).

At mid frequencies you can achieve a wide range at comparatively low power. Used for example in short wave radio, a few watts can bring you across the atlantik ocean.

Low and mid frequency ranges are spreading more or less undirected.

The higher the frequency goes, the more it is spreading directed. This is used e.g. in dish antennas for microwaves. Also the higher the frequency, the less is the penetration into solid or liquid material. For example you may be able to perfectly receive an AM station within a building built from steel reinforced concrete. Your FM reception (typically higher frequency than AM) may be worse and your cellphone reception (even higher frequency) may be next to impossible within that same building.

And, you may not be aware of this, light, too, is a form of electromagnetic radiation. And the properties of light are much diffferent from those of conventional radio frequency waves (e.g. you can transport light via an optical fiber). But you cannot generate light with a resonant LC circuit or any other kind of electronic resonator. Instead you use different physical phenomena like heat, laser, LED etc.

On top of it: don't mix modulation schemes (like AM, FM and all the others that you may not even have heard of) with transmission frequencies. It is by convention (and history and certain technical reasons of optimized usage of bandwidth) that some freqeunca ranges are used mostly with certain modulation schemes. However, that's no physical law.

Ceterum censeo: follow Kris' last post.




Read this Wikipedia article for some background.

 

[Electro132]

This thread makes me think of Chopin's Minute Waltz. He was inspired to write it when he saw a dog chasing its tail.

Electro132, it would really help if you EXPLAIN WHAT YOU WANT TO DO.
Not the technical details of what you think you want, but the OVERALL AIM OF YOUR PROJECT. Include lots of background information, and references to any Internet-accessible material that relates to what you want to do.

Here's some of the things i;ve been reading on:

http://www.quadibloc.com/science/freqint.htm

http://en.wikipedia.org/wiki/Electronic_oscillator

Let me know what you think

 

[Electro132]

Obviously it seems to you that electromagnetic radiation is all the same regardless of frequency (as can be seen from your naive requirement for a 0...3000MHz range).
That is not the case.
The character of electromagnetic radiation changes remarkably with frequency.
At very low frequencies you need super big antennas. You are rewarded with electromagnetic waves that can penetrate deep into and through solid or liquid material. This is used e.g. for VLF (very low frequency) communication from and to submarines (sorry for the military aspect here).

On top of it: don't mix modulation schemes (like AM, FM and all the others that you may not even have heard of) with transmission frequencies. It is by convention (and history and certain technical reasons of optimized usage of bandwidth) that some freqeunca ranges are used mostly with certain modulation schemes. However, that's no physical law.

Ceterum censeo: follow Kris' last post.

Read this Wikipedia article for some background.

I said anywhere between 0 - 3000 Mhz will do. Ok lets just say from 50 khz - 1600 Ghz. Would this be achievable?

Also, the positive goes into the oscillator and is going to be mixed into an IC (model TDA7000) where the local oscillator signal and chosen frequency (FM) from a tuning circuit (coil, 39 pf and 47 pf capacitors as an example) to which a signal should be generated by the chip. This should then get amplified. In a nutshell, the signal should be under 3000 Mhz and can be amplified to make the wave form bigger or smaller so i can see how much force effect it has on certain objects ( stone, glass, plastic cd covers, etc..) in the experiment.

 

[Harald Kapp]

model TDA7000

That IC is a fM radio receiver for an input frequency range from 1.5MHz to 110MHz. Your

50 khz - 1600 Ghz

are way out of the operating range of that chip. What for and with what would you mix your signal anyway?

Your throwing around numbers and circuit principles. But, I'm sorry to say, you don't seem to have grasped the tiniest bit of what this is all about. As Steve told you in one of the earlier answers, you will need different kinds of oscillator for different freqeuncy ranges. Certainly of the range you envision.

Of course you can build an LC circuit and tune it to any frequency you like. But only in theory. For low frequencies, the components quickly become unmanageably big.
For high frequencies the components become very small.

And the LC-resonator is only part of the problem. A resonator per se will not generate any oscillations. You would need an amplifier and some feedback to achieve a loop gain =1 for stable oscillations. No amplifier I know is able to work over the range you give. Low frequency amplifiers are constructed differently from high frequency amplifiers.

After the amplifier comes the antenna.As has been said somewhere else in this lengthy thread before, an antenna has to match the wavelength of the signal for effective operation. Normally you'd use a lambda/4 or lambda/2 length antenna, lambda being the wavelength of the signal.
lambda= v/f where v= speed of light, f=frequency. I leave it to you to determine the wavelength and the required antenna length for your frequency range.

Get a firm standing in the basics of electrical engineering before venturing into such a demanding realm.

 

[KrisBlueNZ]

Electro132, I think you need to learn a great deal more before you will even be able formulate your questions in a meaningful way. You have consistently refused to explain the purpose of, and application for, your project. Harald is a valuable resource and you are wasting his time.

 

[BobK]

But at least he is amusing some of us.

So now it seems that he wants to determine the force applied by electromagnetic waves on stone, glass and plastic cd covers. I guess someone has to do it.

Bob

 

[dietermoreno]

Ok lets just say from 50 khz - 1600 Ghz. Would this be achievable?

No.

As mentioned already, a 50Khz radio transmitter would need to run antenna wire underground for dozens of miles like the navy does for ground penetrating and sea penetrating radar and communications, but it could be generated with an LC circuit, although the components in the LC circuit would need to be very big. More coils lowers the frequency. The relationship is roughly logarithmic because of the 1/sqrt in the LC frequency synthesis equation. If it takes 4 of my 1,000 coil guitar pickups to recieve 780 KHZ (4,000 coils total), and the relationship is logarithmic, you do the math how many coils you will need for 50KHZ. If the relationship was log base 10, then that would mean that to lower the frequency 10 times you would need to increase number of coils by 10^10 times, so your inductor would be hundreds of feet long. This is okay when you are the navy, but not when you are trying to build the radio transciever in your bedroom. So RC circuits are usually used for audio frequencies and the frequency of your windshield wipers on your car, but RC circuits don't generate or receive RF, as there is no magnetic field component in RC circuits.

1600GHZ=1.6THZ I don't think we have transmitters in the THZ range yet. Infra red is in the THZ range. As already mentioned, light is a form of electromagnetic radiation, but you don't generate it with a radio transmitter, you must use other physical means like a light bulb, LED, or laser.

Transmitters in the microwave range don't use oscillator circuits, they use klystron tubes.

Also, the positive goes into the oscillator and is going to be mixed into an IC (model TDA7000) where the local oscillator signal and chosen frequency (FM) from a tuning circuit (coil, 39 pf and 47 pf capacitors as an example) to which a signal should be generated by the chip. This should then get amplified.

There is no positive and negative. An audio signal is alternating current. You mean ground wire and hot wire.

FM isn't a selection of frequencies. VHF FM rock radio is a frequency band. FM is a modulation scheme.

You can use any frequencies with FM, but for the best fidelity (which is the goal of FM), shorter wavelengths are desired so nearby stations do not interfer. VHF allows stations only 20 miles away from each other to not interfer with each other. That is why aviation uses VHF (aviation still uses AM VHF), so the towers do not interfer with each other. Compared to a news station in the medium wave band in Chicago can be heard in Kentucky (I've tried this before to listen to Bears games while on a road trip to Mammoth Cave and it worked with a lot of static).

In a nutshell, the signal should be under 3000 Mhz and can be amplified to make the wave form bigger or smaller so i can see how much force effect it has on certain objects ( stone, glass, plastic cd covers, etc..) in the experiment.

Radio waves don't effect non conductors.

What are you trying to build, a teleportation device?

But at least he is amusing some of us.

So now it seems that he wants to determine the force applied by electromagnetic waves on stone, glass and plastic cd covers. I guess someone has to do it.

Bob

I think he is trying to build a teleportation device.

 

[Electro132]

As already mentioned, light is a form of electromagnetic radiation, but you don't generate it with a radio transmitter, you must use other physical means like a light bulb, LED, or laser.

Transmitters in the microwave range don't use oscillator circuits, they use kelestron tubes.

So you mean to tell me that i can increase and decrease the amount i am outputting with an LED?

There is no positive and negative. An audio signal is alternating current. You mean ground wire and hot wire.

What is the difference with ground wire and hot wire?

FM isn't a selection of frequencies. VHF FM rock radio is a frequency band. FM is a modulation scheme.

Radio waves don't effect non conductors.

Ok that makes sense. But i can still select the frequencies right? As i know that 0.22 pf, 0.001 uf, etc... is available at the store so this shouldn't be too hard to build.

radio waves can effect non conductors as they produce sound after going through the diode or demodulator. This tells me that it can be amplified and outputted to a degree that it can vibrate glass on a high pitch thus meaning it is quite possible. Care to try it with me but in different places? I'm pretty sure it will work.

On top of that i found out with a crystal radio set how i can save heaps of money on my electricity bill. Pretty cool huh?

 

[KrisBlueNZ]

Are you for real? Or are you a...

BTW I can tell you how to save money on your electricity bill using a crystal radio.

1. Turn off all the appliances in your house.
2. Build a crystal radio receiver.
3. Connect it to the mains supply.
4. While grasping an earthed water pipe with one hand, grab the crystal set with the other hand.
5. Voila! No more electricity bills.

 

[BobK]

You will have a lot more luck vibrating glass or plastic using sound.

Bob

 

[Electro132]

Are you for real? Or are you a...

BTW I can tell you how to save money on your electricity bill using a crystal radio.

1. Turn off all the appliances in your house.
2. Build a crystal radio receiver.
3. Connect it to the mains supply.
4. While grasping an earthed water pipe with one hand, grab the crystal set with the other hand.
5. Voila! No more electricity bills.

Lol no i'm for real. Technically you and i have completely different mind sets. But overall you're ok. The Crystal Radio is just a demo example of something bigger and a much more powerful construction. Think about what it is. I found it quite interesting....

 

[Electro132]

You will have a lot more luck vibrating glass or plastic using sound.

Bob

Ok i respect that. So let's just say i moved the tuner from my previous ranges to somewhere like 87.7 Mhz - 108.7 Mhz, now would that be more realistic to make?

I was thinking along the lines of FM/AM and maybe further up (Bluetooth/Infra-red - wireless) but not too high. I reckon it would need a decent coil turn but not that long.

 

[BobK]

Why are you talking about a tuner? I thought you were trying to PRODUCE EM waves, not receive them?

Bob

 

[davenn]

I think he was trying to do both, Bob
but electro132, you are wasting your time using a band that is full of hi power radio transmitters .... their signals will overpower the weak signal from your transmitter

Dave

 

[Electro132]

Why are you talking about a tuner? I thought you were trying to PRODUCE EM waves, not receive them?

Bob

The tuner chooses the frequency and the amplifier is used to increase the penetration level of it. So basically what i'm saying is this:

Tuner chooses frequency - - - - So far this frequency just does this to the wall

Diagram 1.1

- - - - - - - [ <-- Wall


Now when i amplify the chosen frequency it should do this:

Diagram 1.2

- - - - - - - [ - - - - <-- You see the penetration? It goes through the wall

Now do you understand why the glass will wobble in the experiment?

 

[(*steve*)]

This thread is totally pointless for us electronics types.

I suggest you go to a physics forum because your ideas are simply too refined for us.

So, with regret, I'll close this thread.