Because 140 Watts of RF power into a load will either radiate "around the world" so to speak or be reflected back to the source with possibly disastrous results. I think you'd better spend some time learning of the possible effects of your experiments on aircraft and public safety communications. You're going to have a great deal of time to reflect on this from the inside of a jail cell.Why would there be any interference? It's only a magnetic field, and it's at resonance too so it interacts very weakly with anything that is off-resonance. I don't understand why there would be any interference with the exception of something at the exact same frequency in a short range being coupled to my transmitting coil. You're thinking of an antenna radiating E and H field at this frequency. It isn't the case. It's not an antenna doing that. It's a coil that just sets up a magnetic field around itself. And its strength decreases with r^3 of the distance anyway so it's not going to interact with anything more than a few meters at max.
I don't see no faraday cage during their demonstrations. They've clearly demonstrated this lighting up a whole TV wirelessly at a TED conference as well as numereous other fairs like CES. I don't understand why everything in the bandwidth of the amplifier would be amplified. Suppose what you said is true, then how in the world do radio towers work? They pump out 100kW easily, how is it they don't amplify everything else in their so called bandwidth?The experiment at MIT was also carried out inside a Faraday cage, so no RF could escape.
When you are using a linear amp, it's not just going to pick the 10Mhz signal you want, it will amplify EVERYTHING in the bandwidth of the amp, sending it to a higher power amp, which again, amplifies EVERYTHING in the bandwidth, and all the things you have connected become antennas.
If you have a room that has a grounded mesh cage on all 6 sides, then it would be "ok to work on", if you don't, it's a lot bigger issue than you apparently realize.
Have you ever been in the transmitter room of a tower? Each oscillator for the different frequencies is VERY tightly controlled, stubs and other filters are added to block all frequencies outside of the licensed bandwidth for each transmitter. The temp is controlled, usually by air conditioning, even in wintertime, due to the power of the Final tubes, which light up the room.I don't see no faraday cage during their demonstrations. They've clearly demonstrated this lighting up a whole TV wirelessly at a TED conference as well as numereous other fairs like CES. I don't understand why everything in the bandwidth of the amplifier would be amplified. Suppose what you said is true, then how in the world do radio towers work? They pump out 100kW easily, how is it they don't amplify everything else in their so called bandwidth?
Don't get me wrong guys, I'm all for learning and RF is not exactly a place to start but this project requires it so I have to. Anyways, please enlighten me on why all the frequencies will be amplified when I've designed this to just oscillate at high power at a certain specific frequency.
Yes, we are aware of the significant harmonic levels present with using a square wave over a sine wave so we're not using a square wave. However, that doesn't mean the sine wave doesn't have harmonics either. We're using a low pass filter that came with our 140W amplifier to suppress those harmonics depending on the cut off frequency of choice. Thanks for the video, it describes the phenomena nicely.This video came up in another thread and will show you very grahpically the differences and harmonics.
by Aaron Carman
by Jake Hertz
by Aaron Carman
by Duane Benson