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John S wrote:
The thread about a new philosophy was about 246 posts long including the drift into mechanisms of photons and quarks. I wish to start this thread by discussing the merits of dipoles with respect to length. I really don't want to start another thread of flames. Please help me do this. Let's confine the discussion to... * It is a wire dipole (keep the wire AWG to practical values, please). * The dipole's length is variable. * It may or may not have wire resistance (state your value). * The source is placed at the center of the antenna. * There is no transmission line. * There are no matching devices. * This is a theoretical discussion but may include practical parameters. EZNEC or NEC, provides answers to these questions, I think. I will do some modeling and I'd like to compare my results to other results. It does. Let's kick them around. There is nothing to kick around unless you want to argue about whether the various NEC implementations provide valid results. What NEC will tell you is that as the .5 wave dipole gets shorter and shorter, the resistive part of the antenna impedance decreases and the capacitive part increases and the patern and maximum gain changes very slightly. As the ratio of resistive input impedance to the wire resistance get smaller, the I^2R losses increase. But don't let that stop you from doing it. People often learn much better from actual doing then they do from lectures. BTW, you have to pay some attention to segmentation and as you get smaller and smaller the segmentation limits just how accurate the simulation is. -- Jim Pennino |
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