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Roy Lewallen wrote:
I don't have Balanis. Can you provide a short quote where he states that the current at the terminals of a two-terminal lumped component are unequal? He doesn't use lumped components and probably for good reason. But here's the quote that allows my analysis. "Standing wave antennas, such as the dipole, can be analyzed as traveling wave antennas with waves propagating in opposite directions (forward and backward) and represented by traveling wave currents 'If' and 'Ib' in Figure 10.1(a)." This means that net total current equals If+Ib. The fact that the feedpoint current occurs at a current maximum point ties both ends down. 'If' must traverse 90 degrees and 'Ib' must traverse 90 degrees in addition to the 180 degree phase shift due to reflection from the open end. Besides the coil, an 8' whip gives about 22 degrees phase shift in a round trip. Adding the 180 degree phase shift due to the open end reflection gives 202 degrees. But we know the phase shift is actually 360 degrees. Where can the additional 158 degrees of phase shift come from except from the coil? Center-loaded mobile antennas are still an electrical 1/4 wavelength. If there's no phase shift through the coil, where's the missing 158 degrees of phase shift taking place? -- 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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