radio waves & electricity

[Disha Karnataki]

hi people,
i would like to ask if at all i can transmit electrical power on radio waves??. If i can do so then i have to increase the frequency of electrical power
at least up-to 15khz or may be much more than 50hz or 60hz. So, by doing so what will happen to the electric power . I mean what will be the resultant .
what can be the output at receiver end? :?:

 

[tpetar]

Re: radio waves & electricity

Hi Disha and welcome to EDABoard forum,


See these materials :


**broken link removed**

https://www.youtube.com/watch?v=bkDrQexg9vI



Best regards,
Peter

 

[BradtheRad]

i would like to ask if at all i can transmit electrical power on radio waves??

Radio waves are electromagnetic waves. Hence the electric power would no longer be electricity.

You can agitate a device electronically so it gives off photons. A radio transmitter does this.

You can set up a device to resonate to the radio waves (photons) of some frequency. A simple 'crystal' set needs no supply.

It extracts power from the radio waves, produces electrical impulses, and gives off sound. By this method you can transmit power by radio waves.

 

[HMS1021]

Re: radio waves & electricity

Hello Disha,

Radio waves are electric power, so we already transmit electric power. The problem is nobody has perfected an efficient method to transport power through the air from one place to another in large quantities, even over short distances.

One way to do this is to make a narrow beam of RF energy that can be pointed at a distant receiving antenna.
To make a narrow beam antenna the antenna must be large, but not as physically measured in meters. It must be large in terms of wavelengths. A wavelength = c/f where c is the speed of light and f is frequency.
A narrow beam antenna would be at least 100 x 100 wavelengths.

Here are two cases:

At 15kHz a wavelength would be c/f = [3x10^8]/[15000] which is 20km so the antenna would be 2000km x 2000km for a 100 x 100 array which is impractical.

At 50GHz a wavelength would be c/f = [3x10^8]/[5x10^10] which is 6mm so the antenna would only be 600mm x 600mm but at 50GHz there are problems: it is not very efficient to produce very high frequency power, the atmospheric loss is very large at this high frequency, the beam is steered by the atmosphere, and other issues.

So, for now, a radio station transmits 50,000 or more watts of electricity in all directions. The energy is spread so thin we each receive 1/1,000,000 to 1/1,000,000,000 of it and then we must use a complicated receiver to amplify it up to a level where we can listen to the radio station.

hms

 

[Disha Karnataki]

Re: radio waves & electricity

thank u peter

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bradtherad ,
then this will not be effecient to transfer lot of power (i.e in MW) right?

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thank u hms1021

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hey peter,
i saw that link given ..
it's mentioned that tesla could transmit power upto 20miles & could lit 20 bulbs & a motor ..
wow when he could lit so many devices then why is that we are not using this technique??
what exactly is it deffecient in??

 

[tpetar]

Re: radio waves & electricity

hey peter,
i saw that link given ..
it's mentioned that tesla could transmit power upto 20miles & could lit 20 bulbs & a motor ..
wow when he could lit so many devices then why is that we are not using this technique??
what exactly is it deffecient in??

Nikola Tesla did that, but he need money for reasearch and he started building Wardenclyffe Tower for this purpose (to distribute electricity power over world), but when financier saw that electricity can not be charged he gave up and project was stopped.

Wardenclyffe Tower
https://en.wikipedia.org/wiki/Wardenclyffe_Tower

https://www.youtube.com/watch?v=jxWsc7y1olg

https://www.youtube.com/watch?v=u6Q1AqcSuIQ


Magic in "Prestige" Movie 2006
https://www.youtube.com/watch?v=4pX-p7ISukE



Best regards,
Peter

:wink:

 

[BradtheRad]

then this will not be effecient to transfer lot of power (i.e in MW) right?

Yes, at present.

One possibility is to improve the efficiency of photovoltaic panels, so they can convert laser beams into electricity at high power. The panel would need to be extremely robust, to endure the strong laser, and to carry the high amperage.

 

[goyop]

The transmission of electrical power is simple in some regards and incredibly complex in others. The primary concern is getting electricity from point A to point B. After that come the percentage of loss. That is why Edison's DC power distribution failed. DC isn't good for distance. The other issues of transmission are fairly high level physics issues.

Your question has more to do with loss. The losses involved with a wireless transmission at this point in time would be excessive. Maybe in a short distance situation with low power demands it would be acceptable. For high power long distance it wouldn't make it. That is why high tension lines are running at over 100,000 volts and higher to reduce losses and increase power carrying capacity.