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Thanks Richard I printed your post. I'll try to learn how to use that antenna modeling program. I am amazed at how engineers have gotten so smart these past few years. It seems impossible that anyone could get smart enough to do something this complex that it models antenna patterns almost immediately. It will sure be satisfying to become able to use this program. Jerry "Richard Clark" wrote in message ... On Tue, 27 Apr 2004 05:53:19 GMT, "Jerry Martes" wrote: I have the two dipoles fed in phase and spaced 1/4 wave apart The anrenna really works well. I'd like to try to improve it but first need to know more about what I'm getting now. Hi Jerry, Well, I presume you've corresponded here enough to recognize the answers to questions fit what the respondent chooses. Open EZNEC; Select the "Open" button that is at the top left of the application; Select the W8JK.EZ design offered; From the string of "" selections, choose "Plot Type"; then select "3 Dimensional" - "OK" (and respond "OK" again to prompt); Finally select the "FF Plot" button at the bottom left. This will generate an X-Y-Z plot of the radiation lobes of this particular antenna design. Clicking and scrolling your mouse over the image will roll and rotate it to allow you to shift perspective. The antenna element spacing is closer than your quarter wave (0.1 in fact), but it gives you a basis to change things and see what happens. This means you can introduce your self to the Wires table (select the "" which is labeled "Wires"). Change something and then look at the antenna (select the Button labeled "View Ant"). To see how your change impacts transmission lobes, select that same button "FF Plot." The Wires table is based on simple XYZ co-ordinates for each end of a wire (segments is an artifice of necessity for the computation engine, once you've laid out the basic form, we can come back to that later). Instead of worrying about clunky transmission lines, you simply replace them with "Sources" that take their place (this antenna has two of them to represent the split feed). You can be anal and build them out of virtual transmission lines, but give yourself a break and ignore that; it is hardly instructive for the first pass. Welcome to the world of modeling. Press more buttons and appreciate the scope of data available for analysis. Return to the "Open" button, and appreciate the variety of simple designs that offer a fairly broad selection of styles. The free version allows quite a latitude of variation, enough to educate you in all the fundamentals of both design and the application. 73's Richard Clark, KB7QHC |
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