11 posts by 8 authors in: Forums > CWNA - Enterprise Wi-Fi Admin
Last Post: April 12, 2007:
  • What? Power over RF?

    Read'em and weep (tears of joy).

    If they could tune this to 2.4GHz, they wouldn't need their transmitter at all. ;-) There's Wi-Fi every where you go.


  • You couldn't have gotten away with posting this yesterday. :)

    Are you crazy? Trasmitting this over 2.4GHz? We have enough problems with that spectrum... :)

  • The entire office can get hair styles like Larry from the Three Stooges for free while they work.

    Shocking technology!

  • What I was saying is that who needs the transmitter part of their solution... The receiver is the best part by far. If they could tune the receiver to 2.4 GHz, they could receive all of that misc Wi-Fi energy everywhere they go instead of having to plug in a transmitter tuned to some other frequency.

    Yes, shocking technology for sure!


  • Isn't this another fool's april day thing ?

    If it is not it is definately shocking, then we would be one step away of adding power and data over RF and that would be like the ultimate thing !

  • By (Deleted User)

    I was teaching a class for the US Navy last year and I made a joke about "Power over Wireless".

    One of my students had a PHD in Physics and she said quite matter-of-factly:

    "That's already been done"

  • Dr. Nikola Tesla was doing something similar in the 1890s, but on a much grander scale.

    Electrical energy can be propagated around the world between the surface of the Earth and the ionosphere at extreme low frequencies in what is known as the Schumann Cavity. The Schumann cavity surrounds the Earth between ground level and extends upward to about 80 kilometers. The electromagnetic waves of extreme low frequencies in the range of 7.8 Hz, the fundamental Schumann Resonance frequency, propagate with little attenuation through the ether and around the planet within the Schumann Cavity.

    About 28% of the power that is generated at the power plants is lost due to the resistance of the wire used in the electrical power grid distribution system. A wireless distribution system based on Tesla?¡é?€??s theories and experiments should have a loss of 6% or less. He also had a design for an amplifier based on scalar waves and taking free energy from the air.

    Well I?¡é?€??ve already stretched the topic of this thread beyond normal limits so I?¡é?€??ll throw in a suggestion to google HAARP. HAARP stands for High Frequency Active Auroral Research Program (HAARP) which is an investigation project to "understand, simulate and control ionospheric processes that might alter the performance of communication and surveillance systems". (and much more)

  • I keep envisioning the Tesla coil in Command and Conquer and smiling at the "hands-on" labs I could do with students that aren't paying attention! :)

  • By (Deleted User)

    I've been reading about this technology for a while as well. It's an interesting subject.

    Tesla was primarily working on this with DC which subjected the participants to static shocks and static cling. This was alleviated by grounding everything but wasn't practical in everyday applications (special shoes, carpet, etc.).

    Using RF as the conduit is interesting. Basically you just create a radio that converts RF back into AC (or even DC) rather than into data or sound (which is effectively just another form of energy). These are relatively low voltages though and should work well with trickle charge systems (i.e., things that take small power and convert it into stored power in batteries over time).

    I don't think the problem was designing a system to do this... the problem I see would be designing one that did it reliably and safely. For example, what happens when a person with a pacemaker comes in contact with the transmitter? Will he or she receive a small shock that gets misinterpreted as heart stimulus and sends the patient into cardiac arrest? Also, batteries that constantly receive charges have been known to lose their capability of draining fully which drastically reduces the charge life of the battery (this may have been resolved though).

    How would the manufacturer deal with Power denial of service (DoS) attacks? Could hackers "steal" power from their neighbors? Could the RF transmitter be a conduit back into the network if it was connected via PoE or Broadband over Power Line (BPL)? How would that RF affect other licensed or unlicensed RF on the same frequency? Is it or will it be FCC approved (I assume it would have to be at some point). Lots of questions...

    I'm not saying this system won't have huge value in the marketplace... I'm just saying it might not be as easy as it looks.


  • Aren't passive RFID tags power over RF?

Page 1 of 2