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#1
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On Thu, 15 Apr 2004 11:34:21 -0400, "JLB"
wrote: If I remember my traveling wave antenna theory, he wouldn't necessarily be loosing 3 dB in the resistors. At higher frequencies more of the power radiates before it gets to the loads, does it not? Jim N8EE Hi Jim, You are right (losing - unless it has diarrhea). What is described is a vertical, half Rhombic, a Military application for many years. This report appears to be about a design from yet another "inventor" who has "discovered" something that confounds the experts. The original poster asked for comments, especially about the resistor (the difference between shorting it and loading it) however, nothing is said about ground. Both of the resistors will require radials, however, there seem to be more specifics missing than that. In other words, what is the leg angle subtended at the fed point? Why not simply feed one end and terminate the other? Seems like a pain to elevate the feed point without some analysis showing why - but then it appears the column was painfully shy of anything technical beyond carpenter scaling. 73's Richard Clark, KB7QHC |
#2
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![]() "Richard Clark" wrote in message news ![]() You are right (losing - unless it has diarrhea). What is described is a vertical, half Rhombic, a Military application for many years. This report appears to be about a design from yet another "inventor" who has "discovered" something that confounds the experts. Dick, I challenge any antenna 'inventor' to invent an antenna that is not described in Kraus' book, at least at the fundamental theory level! Haven't seen one yet and I've been reading QST for over 30 years (not to mention my dad's collection that goes back to 1942). By the way, I 'invented' an interesting antenna several years ago, which I call the half-quad. The best way to describe it is dto picture a diamond shape quad, fed at the side corner, half buried in the ground. Shows some interesting patterns on the good ol' AO program. I came up with a three element version with one feed point (center element). You can change directions by switching a capacitor or inductor in and out of the two 'outside' elements. It didn't use terminating resistors. I couldn't get a multiband version to work. (and, no, I haven't built it yet) Jim N8EE (and yes, I qualify for the OT club but don't want to admit it quite yet). |
#3
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If I understand your description correctly, I'd be highly suspicious of
the results from AO or any other MININEC-based program because of the antenna's relatively low height. I recommend that you model the antenna with an NEC-2 based program using the Sommerfeld ground model (called "high-accuracy" ground in EZNEC) -- otherwise you might be pretty disappointed when you actually build it. Be sure to make note of the strength of the pattern as well as the shape of the NEC-2 program results, unless you're using the antenna only for receiving. Roy Lewallen, W7EL JLB wrote: . . . By the way, I 'invented' an interesting antenna several years ago, which I call the half-quad. The best way to describe it is dto picture a diamond shape quad, fed at the side corner, half buried in the ground. Shows some interesting patterns on the good ol' AO program. I came up with a three element version with one feed point (center element). You can change directions by switching a capacitor or inductor in and out of the two 'outside' elements. It didn't use terminating resistors. I couldn't get a multiband version to work. (and, no, I haven't built it yet) Jim N8EE (and yes, I qualify for the OT club but don't want to admit it quite yet). |
#4
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I challenge any antenna 'inventor' to invent an antenna that is not
described in Kraus' book, at least at the fundamental theory level! Which addition? 73, Chip N1IR |
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