A fellow came to me convinced that capturing RF energy from cell phones, and radio and TV waves was free energy. He couldn’t wait to invest in these pocket sized antennas that have achieved the same 37% energy reception efficiencies as do the most expensive solar cells:.
http://www.sciencedaily.com/releases/2013/11/131107154818.htm I told him to not believe everthing he hears and you Amsat radio guys might get a kick out of my response: -------------------------------------- Thanks for sending me this interesting example of hype gone ridiculous. I was glad to receive it. The problem is apples and oranges. Yes, they got ”37% efficiency, similar to the most expensive solar cells”, but the difference is that solar energy imparts about 100 watts of energy per square foot on a solar panel – remember, ONE HUNDRED WATTS/sqft. The amount of energy from a Cell tower onto a small antenna 1 mile away from the cell tower (typical) is only 0.000000000004 Watts. So there is about a one hundred trillionth of the practicality. Or another way to look at it. If you could hold their RF energy collecting antenna 1 inch from the cell phone tower (not one mile), to get more power, then the most power he could get would be only 3 watts. Still nothing close to what the sun provides. Plus, he would be absorbing all the power from the cell phone tower making it useless, plus the energy is not free. SO to get the same power as a palm sized solar panel, his RF capture antenna would have to be ONE INCH away from THIRTY cell phone towers. And, to generate that same 100 watts worth of RF energy, it takes about 300 watts of electrical power. (1 inch away) All to deliver about 1 Watt of power compared to the Sun which is free. Thanks. A great lesson in hype! Bob Bruninga, WB4APR _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
