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w4jle wrote:
Current through a coil in an antenna. If we feed an antenna at the current point, the current decreases as the voltage increases along the antenna element from feed point to end.. That being said, a coil replacing a segment of an antenna (in order to physically shorten it) will exhibit the same properties (relating to currents) as the segment it replaced. Yep, if the feedpoint impedances are the same and both are lossless, that has to be true. Here's a repeat of a diagram I drew earlier. -----y----------x-----FP-----x----------y----- 1/2WL dipole -----coil-----FP-----coil----- loaded dipole Assume the physical length of the loaded dipole is 1/4WL. Each coil replaces the section between 'x' and 'y'. The currents at 'x' and 'y' are quite different, being 1/8WL apart. Consider an 8 foot center-loaded 75m mobile antenna. 87% of the electrical length of the antenna is in the coil. -- 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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