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Big difference between LPDA and mono bander.
With the LPDA the antenna boom is actually part of the feed system for
the elements. If you install the choke/balun at the feed point, then
tape the coax to the boom you have negated choke/balun at the feed point
because the cable is tightly coupled to the RF hot boom.
Not so with a mono bander like the OWA and others where the boom is
insulated from the driven element. Tape or clamp the balun/choke any
> Guess I need a bit of clarification on a point or two. I am thinking
> monoband yagi, not LPDA for my questions.
> 1. You state
> "the coax needs to be routed down the boom tied to the shield."
> I take this to mean the shield of the coax should be connected to the boom
> close to the feed point.
> 2. You state
> "If you tape the coax to the boom the balun needs to be at the point
> where the coax leaves the boom to go to the tower, not out at the feedpoint"
> I take this to mean placing rhe balun after the 90 degree turn from the
> horizontal boom to the vertical mast. Will taping the balun and coax down
> the mast have detrimental affects? Will the balun need to be spaced from the
> mast and if so how far?
> In the case of an OWA type antenna with split dipole feed(dipole insulated
> from the boom), would the coax shield get grounded to the boom near the feed
> point and the balun placed after turning down the mast?
> Arne N7KA
> -------------- Original message --------------
> From: "Tom Rauch" <firstname.lastname@example.org>
>>> I am close to putting my Tennadyne T-6 back up. When I took
>>> it down it had the prescribed Coax Balun on it and it
>>> showed it's age. For the last month or so I have had the
>>> antenna on a short perch in the yard with a Ferrite Bead
>>> Balun on it and it sweeps fine using an analyzer and I have
>>> even made a few DX contacts on it. The balun I am using is
>>> a W2AU by Unadilla. I have searched different archives and
>>> the only one with any significant information is one I
>>> started on eHam some years ago.The old Tennadyne maker
>>> specifically said he had not tested a ferrite balun and did
>>> not recommend them. The reasons I would like to use the
>>> Ferrite Balun are:
>> Watch how you run the coax. If you use a balun and then tape
>> the coax to the boom (which is hot) you totally defeat the
>> reason for having a balun. If you tape the coax to the boom
>> the balun needs to be at the point where the coax leaves the
>> boom to go to the tower, not out at the feedpoint, and the
>> coax needs to be routed down the boom tied to the shield.
>> 73 Tom
>> TowerTalk mailing list
> TowerTalk mailing list
R. Kevin Stover, ACØH
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