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#1
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#2
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In article ,
W5DXP wrote: Don't forget the Arrow Open Stub J-pole. http://www.arrowantennas.com/osj/j-pole.html There is (or was) a nice writeup of this variety on Cebik's web site. He refers to it as a "variant J-pole". The feed arrangement is different (it's open at the feedpoint, rather than being fed a few inches above a short), and the arm lengths are different than with a "classic" J-pole. The current distributions are different, of course, but the radiation pattern is only very slightly different than the "classic" variety. I have one of these dual-band types in my "go-kit" (it's actually a knock-off, built locally based on the plans that Arrow used to have on their web site) and it's served me well. I usually mount it at the top of a two-or-three-segment aluminum mast, sitting in an old hefty movie-camera tripod base. Much too large and heavy for a vehicle, of course, but I imagine you could build a somewhat-similar open-stub J-pole using much lighter materials (e.g. fiberglass whips with wire fastened inside or outside). |
#3
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On Tuesday, February 18, 2014 6:26:40 PM UTC-6, David Platt wrote:
The feed arrangement is different (it's open at the feedpoint, rather than being fed a few inches above a short), and the arm lengths are different than with a "classic" J-pole. If one will ignore the long 2m element and draw a schematic of it just for the 70cm band, one will realize that it is actually just a standard Zepp antenna. ![]() |
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