I believe an ATU or other matching network provides a conjugate match. That results in optimum power transfer because the RF current and voltage are in phase and the SWR meter will read 1:1.
When there is a mismatch, as indicated a high SWR, the finals in the rig do not see the optimum load impedance for efficient power transfer so they do not operate at optimum efficiency. Lower efficiency means that more of the d-c power applied to the finals is consumed in heat instead of RF, and the amount of heat the finals must dissipate goes up. I believe that's what led many Hams to mistakenly believe that the "reflected" power was being absorbed in the finals. The solution is, of course, to provide a proper termination for the finals. When the antenna or other load doesn't present the right impedance, a matching network (a.k.a. 'tuner' or ATU) can be inserted to provide one. Ron AC7AC -----Original Message----- Most likely the K3 is putting out 60 watts, real watts. The wattmeter is also probably correct reading 80 watts forward, with 20 reflected, equal to a net 60 watts. And 60 watts is radiated by the antenna. No power get reabsorbeds by the amp because it is presenting a congugate match. i.e. any power coming back from the antenna sees a perfect mismatch at the transmitter and gets re-reflected back to the antenna. Explained 100 times better than I can by Walt Maxwell in his books "Reflections" or maybe the current one is "Reflections III" something like that. Anyway the point is, none of this rf power heats up the finals. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
