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On 7 ene, 04:25, (Richard Harrison) wrote:
art wrote: "You did not 'determine" radiated power.....period" Exactly right. Power in the near field is largely reactive. To determine radiated power you measure the in-phase volt-amperes with a wattmeter. The multimeter on the hood maximizes output same as a Bird wattmeter for practical results, but you hanen`t quantified watts out. Best regards, Richard Harrison, KB5WZI Hi Richard, You can determine radiated power and radiation pattern by near field measurements (theoretically). Please search for "poynting theorem" and "Huygens principle", "Huygens Source" or "Fresnel diffraction theory". Most texts require differential vector calculus. Because determining radiated power based on E- and H-Field measurement is generally not feasible for amateurs (and even for many professionals), I suggested another approach based on E-field measurements and EM simulation. As absolute E-field measurement and EM simulation are within the reach of amateur radio operators, one can both tune for maximum field and determine absolute radiated power. Of course you don't know how much power is dissipated in nearby structures (buildings, etc). Best regards, Wim PA3DJS www.tetech.nl |
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