Can Ultra-Low Frequency EM Waves Revolutionize Global Communication?

[Stanley514]

I wonder if there exist some type of electromagnetic waves, which do not experience virtually any kind of interference and could freely go through the world.I know there exist some ELF communication with submarines and ELF waves could penetrate deep into the ocean.Does that mean that the lower frequency we have the farther it will go?As I know there is no lower limit to frequency of EM waves.What if we have frequency of 1/millionth of hertz?Will it penetrate the Earth core?I think we would use such comunications to avoid or reduce payment to Internet or cellphone providers.We could use pulsed sub-ELF waves which would produce billions of pulses per second and encode bits in such way.One problem here could be size of antenna.But I know that human brains produce ELF wave which could be picked with encefalographs.How brains are able to generate them?

 

[JaredJames]

Ridiculous content of this post aside, which we'll get to later, I like this bit:

What if we have frequency of 1/millionth of hertz?

We could use pulsed sub-ELF waves which would produce billions of pulses per second

1hz = 1 pulse per second.

To generate "billions of pulses per second" with a "frequency of 1/millionth of a hertz" would require billions of signal generators.

How that would reduce costs I have no idea.

I recommend you read the wiki on this to get a better understanding of ELF: http://en.wikipedia.org/wiki/Extremely_low_frequency

Pay important note to the issues of wavelength and transmitter size.

By continuing to lower the frequency you compound these problems - particularly data transmission rate.

This ignores the other effects of trying to send a signal "through the earth".

 

[Drakkith]

Jared, I've actually always wondered why exactly you can transmit more data per second using a higher frequency? I don't know any details of how it all works. All I think I understand is more hertz = more throughput.

 

[JaredJames]

Well think of it like a digital signal (on or off = 1 or 0) - same for analogue but digital is easier to picture.

Let's say it's at 1hz then you can send 1 on or off per second.

If I wanted to send you the letter A in binary (01000001) it would take 8 seconds.

By increasing the frequency to 10hz I can send it in under a second.

That's why these ELF signals can only transmit a few characters over a long period.

 

[Drakkith]

I have no idea how information is transmitted using EM waves. Why does 1 hertz = 1 bit per second? Does the transmitter/reciever only send/recieve as many bits per second as the hertz of the signal?

 

[JaredJames]

The number of hertz is how many times the signal is repeated per second. (I assume you know what the frequency of a wave is?)

Digital signals transmit binary information in the form of on/off (1's and 0's).

Picture it in the form of an electrical signal where 0V = off and 5V = on.

To send the letter A I'd have to send the binary form which is 01000001.

If you convert that to voltages you get 0V 5V 0V 0V 0V 0V 0V 5V.

If the frequency is 1hz, that means I can transmit one voltage per second. If the frequency is 8hz I can send 8 voltages per second and so on as you increase the frequency.

So for 1hz, each second I either apply 0V or 5V, depending on the next number in the sequence (0 or 1).
And for 8hz, each 1/8th of a second I either apply 0V or 5V.

With me so far?

A good place to start is here so far as digital signals go: http://en.wikipedia.org/wiki/Digital_signal

A bit is made up of a certain amount of binary data.

 

[Stanley514]

To generate "billions of pulses per second" with a "frequency of 1/millionth of a hertz" would require billions of signal generators.

Even this scenario doesn`t seem to be a complete imposibility because modern computer processors are having billions of transistors.Microantennas could be less complicated than that.

I've actually always wondered why exactly you can transmit more data per second using a higher frequency? I don't know any details of how it all works. All I think I understand is more hertz = more throughput.

I wish to know if this is a case if you have pulsed signal.For example lightning generates VLF waves.If you have lightning striking million times per second doesn`t it mean that you could encode millions of bits per second?
Also I still didn`t hear what size of antenna you need for ELF waves?Could there be something small?

 

[JaredJames]

Even this scenario doesn`t seem to be a complete imposibility because modern computer processors are having billions of transistors.Microantennas could be less complicated than that.

Also I still didn`t hear what size of antenna you need for ELF waves?Could there be something small?

Processors have nothing to do with Microantennas, completely different. Apples and oranges.

Did you read the article I linked to? To generate an ELF wave you need a huge antenna and a lot of power.

Because of this huge size requirement and, to transmit internationally using ELF frequencies, the Earth itself must be used as an antenna, with extremely long leads going into the ground.

Both sites used long power lines, so-called ground dipoles, as leads. These leads were in multiple strands ranging from 22.5 to 45 kilometres (14.0 to 28 mi) long. Because of the inefficiency of this method, considerable amounts of electrical power were required to operate the system.

Please read the article. They couldn't install a transmitter on a submarine for basic "few characters per minute" communication due to the size.

 

[JaredJames]

I wish to know if this is a case if you have pulsed signal.For example lightning generates VLF waves.If you have lightning striking million times per second doesn`t it mean that you could encode millions of bits per second?

Each lightning strike would be its own transmitter.

So first you would need your billions of transmitters and then you would need to have your billions of receivers.

A transmitter that can send at 1hz can only transmit once per second - you can't have it send a 1hz signal a million times in a second.

 

[Stanley514]

To generate an ELF wave you need a huge antenna and a lot of power.

Do you have some explanation how human brains generate ELF waves which could be picked on a skull?

 

[Drakkith]

So when a signal is transmitted, does the frequency produce a "pulse" of voltage in step with it for the receiver? I'll browse around wikipedia and try to find a good article unless you know of one. Thanks Jared.

 

[JaredJames]

So when a signal is transmitted, does the frequency produce a "pulse" of voltage in step with it for the receiver?

Correct.

 

[JaredJames]

Do you have some explanation how human brains generate ELF waves which could be picked on a skull?

You're confusing issues.

In order to use ELF for communication you need to generate the signal as outlined in that article using an very big antenna and a lot of power - I cannot stress how much I need you to read that before this can continue.

 

[Drakkith]

Do you have some explanation how human brains generate ELF waves which could be picked on a skull?

From the Brainwaves article on Wikipedia:

The brain's electrical charge is maintained by billions of neurons. Neurons are electrically charged (or "polarized") by membrane transport proteins that pump ions across their membranes. When a neuron receives a signal from its neighbor via an action potential, it responds by releasing ions into the space outside the cell. Ions of like charge repel each other, and when many ions are pushed out of many neurons at the same time, they can push their neighbors, who push their neighbors, and so on, in a wave. This process is known as volume conduction. When the wave of ions reaches the electrodes on the scalp, they can push or pull electrons on the metal on the electrodes. Since metal conducts the push and pull of electrons easily, the difference in push, or voltage, between any two electrodes can be measured by a voltmeter. Recording these voltages over time gives us the EEG.[4]

This isn't like an antenna. The EM picked up by the electrodes are not EM waves that are sent out by the brain, but merely the movement of ions in the brain.

 

[Stanley514]

So there is no even theoretical possibility of free distance communication between people?

 

[Drakkith]

So there is no even theoretical possibility of free distance communication between people?

Not in the way you were thinking, no. It all kind of depends on what you mean by free distance communication.

 

[JaredJames]

So there is no even theoretical possibility of free distance communication between people?

No, if you mean free to be "without monetary expense".

Either way, someone has to buy the equipment and maintain it - maintenance costs are there regardless of what system is used. Even me speaking to my family involves wear and tear on my body and so the body has to use energy to maintain it.

 

[Stanley514]

It all kind of depends on what you mean by free distance communication.

I mean possibility for people to exchange information between any part of a globe without any providers or expensive equipment such as satellite,cables,radio towers etc.
I know there exist quantum teleportation of information.Does it work through huge distances?

 

[Drakkith]

I mean possibility for people to exchange information between any part of a globe without any providers or expensive equipment such as satellite,cables,radio towers etc.
I know there exist quantum teleportation of information.Does it work through huge distances?

Nope. Not as far as we know currently.

 

[JaredJames]

I know there exist quantum teleportation of information.Does it work through huge distances?

And how much does it cost for the equipment to synchronise two particles? Not to mention the R&D costs?

Plus, that means I need a particle for every other communication device on the planet - otherwise I could only ever speak to one person.

I see costs sky rocketing right now.

Like I said, you've always got maintenance costs and as such can never have free communication over distance.

 

[pallidin]

The following link provides a HIGHLY extensive chart on US frequency allocations:

http://www.ntia.doc.gov/osmhome/allochrt.pdf

Enjoy!

 

[Stanley514]

We need to make clear if you absolutely need to have antenna which size would be comarable to wavelength of it brodcast.In wikipedia article about ELF is writting that they try to use some electric shortening to make size of ELF antenna smaller.Some wokie-tokies work on frequency 50 MHz,which seems to be much bigger wavelength then size of wokie-tokie itself.

 

[JaredJames]

We need to make clear if you absolutely need to have antenna which size would be comarable to wavelength of it brodcast.In wikipedia article about ELF is writting that they try to use some electric shortening to make size of ELF antenna smaller.Some wokie-tokies work on frequency 50 MHz,which seems to be much bigger wavelength then size of wokie-tokie itself.

Firstyl, you're confusing frequency with wavelength. 50 MHz = 50,000,000Hz = 50,000,000 per second.

That is hardly going to be a long wavelength anyway. None-the-less it's still the longest of the available in the EM spectrum:

http://en.wikipedia.org/wiki/File:EM_Spectrum_Properties_edit.svg

Note how as frequency increases,the wavelength drastically decreases. For the handheld it would be around 10m to 100m in length.

Now, Long Wave transmitters are made of long cables suspended between poles (or something to that effect), allowing you to produce the required wavelength (around 1000m in length).

Regardless of all this, there is a massive difference between creating a wavelength of 100m and one that is 299,792,458m on a handheld device.

You are still ignoring the transmission problems with low data rate.

And the fact there will be significant maintenance costs which someone has to pay for.

 

[Stanley514]

And the fact there will be significant maintenance costs which someone has to pay for.

There is also a stupid problem when person has to pay for few services such as Internet,cord phone and cable TV having only one connection - for example a TV cable.Theoretacally you could make phone calls for free and watch movies through Internet for very low price but you need to have IP phone as well as people whom you are calling to.
Of couse it doesn`t make a difference but companies charge you for ``service`` and virtually for nothing.
There is still examples in physics when small objects could emit ELF.For example black body radiation suppose to emit in all the spectrum including ELF and ultrocold atoms especially.The problem of transmission rate could be solved by using huge amounts of microantennas.Some scienticts already trying to fabricate infrared nanoantennas and claim that mass production will cost cents per yard.
I think that use of short wave radios could also reduce price of comunication.For exampe frequency 30 MHz allows send signals up to 6.000 km in distance.U.S. soldiers used such type of radios in Vietnam.I don`t know why it is not used in comunication.

 

[JaredJames]

There is also a stupid problem when person has to pay for few services such as Internet,cord phone and cable TV having only one connection - for example a TV cable.Theoretacally you could make phone calls for free and watch movies through Internet for very low price but you need to have IP phone as well as people whom you are calling to.
Of couse it doesn`t make a difference but companies charge you for ``service`` and virtually for nothing.

You're joking right? Do you know how much technology and other stuff is between you and the person you're interacting with? The fact you could make such a statement shows how ignorant you are to what it takes to operate and maintain the services.

There is still examples in physics when small objects could emit ELF.

And the range of that signal? Tiny. Not even remotely useful.

The problem of transmission rate could be solved by using huge amounts of microantennas.Some scienticts already trying to fabricate infrared nanoantennas and claim that mass production will cost cents per yard.

Infrared =/= ELF. They are completely different so let's not go there.

I think that use of short wave radios could also reduce price of comunication.For exampe frequency 30 MHz allows send signals up to 6.000 km in distance.U.S. soldiers used such type of radios in Vietnam.I don`t know why it is not used in comunication.

Shortwave radios have a wavelength of 11m at 30MHz. Rather far off the figure above for ELF.

Shortwave gets a lot of interference. Has extremely low bandwidth and is only useful for long range at certain times of the day. And not to mention energy requirements.

Regardless, all of the above shows you don't understand the technology we already have so I don't see how you can plug something new. Your posts are full of misconceptions.

 

[Evo]

This thread is pointless.