Renewable Energy Questions/Discussion > Renewable Energy Q&A
any radio experts on here?
rossw:
--- Quote from: welshman on July 30, 2021, 04:15:54 am ---I would like to change the frequency of a radio wave, shifting it from one to another. so as to be an antenna for one frequency and send it out in another frequency, with a high ratio of change. I would like to do this without any electronics or processing.
is this even possible or am I talking nonsense?
--- End quote ---
You can (fairly easily) do a tripler, that you stick in say 430MHz and get the 3rd harmonic at 1290MHz.
(Square waves are the sum of all the odd harmonics).
So you need something to "mess up" the input signal, then some serious filtering to extract the harmonic.
Your output power is way down on the input, but it can be done.
If you're talking about anything near 50/60Hz, forget it. The filters would be monsters.
If you want outputs below the input, the only mechanism I know of is a divider or a mixer, but you're still going to need active components for a divider, and a mixer will need an excitation source, and filtering (you will get sum+difference, so you need to filter out the sum). None of this will be efficient at decent power levels.
welshman:
--- Quote from: rossw on July 30, 2021, 06:35:17 am ---
--- Quote from: welshman on July 30, 2021, 04:15:54 am ---I would like to change the frequency of a radio wave, shifting it from one to another. so as to be an antenna for one frequency and send it out in another frequency, with a high ratio of change. I would like to do this without any electronics or processing.
is this even possible or am I talking nonsense?
--- End quote ---
You can (fairly easily) do a tripler, that you stick in say 430MHz and get the 3rd harmonic at 1290MHz.
(Square waves are the sum of all the odd harmonics).
So you need something to "mess up" the input signal, then some serious filtering to extract the harmonic.
Your output power is way down on the input, but it can be done.
If you're talking about anything near 50/60Hz, forget it. The filters would be monsters.
If you want outputs below the input, the only mechanism I know of is a divider or a mixer, but you're still going to need active components for a divider, and a mixer will need an excitation source, and filtering (you will get sum+difference, so you need to filter out the sum). None of this will be efficient at decent power levels.
--- End quote ---
thank you for your time and input. i see you mention square waves. what if we tried to capture triangle, sawtooth and sine. does that change anything? i don't understand, but i think you can see what i'm asking about. i would like to design a working prototype. even if it turns out to be inefficient and then work from there on it. i kind of, at this stage, just want to see 50hz ac coming out of a rf antenna outlet with no electronics. if that's even possible and if that's not possible, what would be the simplest amount of electronic components needed to make it so.
welshman:
--- Quote from: rossw on July 30, 2021, 06:35:17 am ---
--- Quote from: welshman on July 30, 2021, 04:15:54 am ---I would like to change the frequency of a radio wave, shifting it from one to another. so as to be an antenna for one frequency and send it out in another frequency, with a high ratio of change. I would like to do this without any electronics or processing.
is this even possible or am I talking nonsense?
--- End quote ---
You can (fairly easily) do a tripler, that you stick in say 430MHz and get the 3rd harmonic at 1290MHz.
(Square waves are the sum of all the odd harmonics).
So you need something to "mess up" the input signal, then some serious filtering to extract the harmonic.
Your output power is way down on the input, but it can be done.
If you're talking about anything near 50/60Hz, forget it. The filters would be monsters.
If you want outputs below the input, the only mechanism I know of is a divider or a mixer, but you're still going to need active components for a divider, and a mixer will need an excitation source, and filtering (you will get sum+difference, so you need to filter out the sum). None of this will be efficient at decent power levels.
--- End quote ---
see these things http://dg7ybn.de/Splitters/coax_online_calc.htm I'm thinking along the lines of having only an input and an output and then instead of just bending the tube once in the middle. bend it multiple times in adjacent directions creating a sine wave shape or triangle shape to the tube or turn the tube into a triangle wave shape metal maybe 8 or so waves. tunable with screws.. would that resonate or something ? magic happen?
rossw:
The wavelength of a 50/60Hz waveform is about 4,000 miles.
Any kind of stripline or resonant conductor is going to be completely unmanagable.
Different shapes make no appreciable difference to anything, except in so far as it may slightly vary the inductance or parasitic capacitance.
You say you're wanting to capture power from an antenna - where do you suppose this energy is going to come from in the first place?
If it's very low frequency (eg, geomagnetic) the coupling is poor and you'll need phenomenally long antennas.
If it's high frequency (eg, commercial radio transmitters) the power density is very low unless you're right on top of the radio station. I cannot think of any mechanism by which you can divide the frequency from the carrier (where the power is) without the use of electronics that will in all probability take more power to operate than the recovered power out.
Yes, relatively low frequency radio waves can be rectified simply using diode junctions (or potentially from suitably constructed joints that naturally form a semi-conductor like corrosion and/or rust can) but that would only leave you with DC, not the 50/60Hz AC you seek.
welshman:
Thanks again for your input. I have managed to figure something out.
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