You are implying that I can arbitrarily increase my power output by detuning my antenna! You are right that reflected power is re-reflected by the source, but there is a sense in which the 'real' power output in my example is 1 kW.
Vic K2VCO /4X6GP > On Jan 13, 2015, at 2:46 AM, Phil & Debbie Salas <[email protected]> wrote: > > "I would like the W2 wattmeter to be able to display "delivered" power, that > is, forward power minus reflected power. This would give a more accurate > indication of power going to an antenna when the SWR is not 1:1. For > example, if the SWR on the line is about 2.5 and forward power indicates 1.2 > kW, there is about 200 watts reflected power. In that case only about 1 kW > (less line losses, of course) is being delivered to the load. It is > misleading to look at just forward power." > > Actually, "delivered power" is pretty much what you are measuring. Remember > that reflected power is re-reflected by the source and adds back into the > forward power. So in your example, you are transmitting 1200 watts, having > 200 watts reflected, then the 200 watts is re-reflected by the source giving > you the 1200 watts. Of course, there will be transmission line SWR-related > losses. > > Phil - AD5X > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
