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alhearn wrote:
If you read Chapter 13, "RF Power Amplifiers and Projects", in the 2004 ARRL Handbook, there are pages and pages of discussion of matching plate or transistor output impedances to 50 ohms output and not once do they ever refer to output networks dissipating or reflecting reflected power. However, the 15th edition of the ARRL Antenna Book goes into great detail about how a match point reflects rearward-traveling waves. If you are designing RF Power Amps, you can simulate load conditions with lumped components. If you are trying to figure out what happens on a transmission line (distributed network) you need to take reflections into account. Transmission lines have reflections; output matching networks and tuners don't. The reflections on transmission lines don't make it past the end of the transmission line -- that's where the reflections take place. Beyond the end of the transmission line, the reflections are seen as mere impedances created by standing waves, which are created by reflections, assuming mismatch. Impedances created by standing waves are merely V/I ratios, i.e. virtual impedances. They are the result of standing waves and not the cause of anything. Physical impedance discontinuities are the cause of reflections that cause standing waves. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
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