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Cecil Moore wrote in message ...
Mark Keith wrote: Bravo. Pretty much sums it all up in a nutshell. No one has shown an example of gross modeling error to date. What is the matter with the one I posted last week with phase- reversing coils as described by Kraus on page 824 of _Antennas_ for-all_Applications_, third edition? If you missed it, look at http://www.qsl.net/w5dxp/current.htm What example? I look at the page, and all I see is a current distribution model for an antenna using stubs. ?? Where is the model of the one using lumped inductance? I tried modeling a couple of antennas myself using multiple 1/2 wave elements and inductance as phasing coils just to test this out. But I used three elements instead of four. I do not see any major change in current distribution when compared to feeding all three with three separate sources. Minimum current is at the ends of each section in both cases. But I do see a bit less gain with the lumped inductance version, and not quite as tight a pattern. This *might* be a point of error, but I'd have to look more carefully into that. It's quite possible that feeding with separate sources is superior in the real world, and it's reflected in the model. But if this is an error in the model, I would think that it only applies to arrays with lumped inductance used for phasing coils. I very seriously doubt this error would apply to modeling short coil loaded verticals. Or even large arrays that used lumped inductance for loading, and not phasing purposes. Like I've said, when I phase elements, I usually use separate sources to feed. That way I can control the phase angle to whatever I want it to be. MK |
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