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#1
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Here are a couple of articles I found.
http://www.qsl.net/pa3hbb/arframe.htm http://www.arrl.org/tis/info/pdf/0207040.pdf The last link is for a 40 meter linear loaded dipole, but I think the formulas should work. GL es 73, Terry, WK0F "news" wrote in message .com... Does anyone have a good source for calculating the length of linear loads for a shortened 40 meter Vertical? I'm experimenting with a 20' vertical and a pair of 10' parallel lines moved the resonant point near the 7 Mhz band. Any suggestions? |
#2
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I saw both these articles but they are still both fairly weak on theory.
K4VX's article was what inspired me to try using a ladder line. He apparently tried several lengths in NEC and then built an antenna from that result. I've done that as well and it gives you a good start but doesn't expose the theory of calculating the loads. Reid's article starts with a very simple model. He makes the load length equal to the "missing" length of the radiator! Then he complicates the analysis with a top hat which he uses to create an "adjustment". That apparently got close and then he pruned till he got resonance in the range he wanted. It wasn't clear how the size of the top hat relates to the length of the load. The ARRL Antenna book has great analysis of the calculation for top hats but no similar analysis for linear loads - at least I didn't find any. Any help appreciated "Terry Ashland" wrote in message om... Here are a couple of articles I found. http://www.qsl.net/pa3hbb/arframe.htm http://www.arrl.org/tis/info/pdf/0207040.pdf The last link is for a 40 meter linear loaded dipole, but I think the formulas should work. GL es 73, Terry, WK0F "news" wrote in message .com... Does anyone have a good source for calculating the length of linear loads for a shortened 40 meter Vertical? I'm experimenting with a 20' vertical and a pair of 10' parallel lines moved the resonant point near the 7 Mhz band. Any suggestions? |
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