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Author Topic: Tap wire winding direction for mobile HF vert ical  (Read 1387 times)
VK5FDMR
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Posts: 7




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« on: July 24, 2007, 06:00:29 PM »

Hi all,

Just looking for an answer to this question....

In regards to a multi tap HF vertical antenna, can someone please tell me in which direction must the tap wire wind up the antenna element?  

I have been told two answers by fellow hams down here. Firstly it is critical to wind the tap wire in a certain direction. Failure to do so wiould result in poor performance or "Other effects". Secondly, it makes no difference which way the tap wire is wound.

Could someone please fill me in on this.

Thanks.

Best 73 de Dave VK5FDMR
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W3LK
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Posts: 5639




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« Reply #1 on: July 24, 2007, 06:24:39 PM »

<<  Firstly it is critical to wind the tap wire in a certain direction. Failure to do so wiould result in poor performance or "Other effects".>>

Baloney!!!

It makes absolutely no difference in which direction the coil is wound.

73,

Lon - W3LK
Naugatuck, Connecticut
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A smoking section in a restaurant makes as much sense as a peeing section in a swimming pool.
KE3WD
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Posts: 5688




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« Reply #2 on: July 24, 2007, 07:32:41 PM »

I second Lon's assessment of this situation.  

They probably also still believe that the water circles down the drain depending upon which side of the Equator you are on...

Resonance is resonance, wind the thing and enjoy.



.
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K0BG
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« Reply #3 on: July 25, 2007, 06:25:44 AM »

There are two issues with this, and I don't know which one you are referring to.

It doesn't make a whit which direction you wind a coil, whether or not it is short tapped to resonant it on a higher frequency. To even suggest a specific direction is junk science.

The other issue is a matching coil used to bring the input impedance up to 50 ohms. Here too, direction doesn't make any difference. This said, one issue with a base matching coil is HOW it is mounted. At least two manufacturers designed the coil so the mast goes through the center of the coil. Doing so flat kill what little Q the coil has in the first place. Perhaps some folks think it looks tidy to do it this way.

Alan, KØBG
www.k0bg.com
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N3OX
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« Reply #4 on: July 25, 2007, 09:28:53 AM »

I read the question to be about Outbackers and other antennas with "wander leads" that make a few loose turns around the body of the antenna (which has a tapped coil inside it)

I think the thought is that there's a difference between winding in the same sense as the interior coil and the opposite sense.

There shouldn't be any practical difference... there are some situations where this sort of thing could matter

The resonant point of my base loaded vertical on 160m actually depends heavily on which way the tap wire goes around the main coil, but that's because *ONE TURN* of the coil makes a big difference  ... I tried to tap halfway around the coil, but the wire either completes that half winding or cancels it depending on which way it goes around the coil.

I don't think *any* of that applies to the Outbacker type antennas... don't they only use the coil *above* where the wander lead plugs in?

73,
Dan
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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
VK5FDMR
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Posts: 7




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« Reply #5 on: July 25, 2007, 04:52:19 PM »

Hi all,

Thanks for your comments re my topic.  As I am just starting out in this hobby, I always try and get to the bottom of things before I go out and do something which I may regret later. There are plenty of people around who will try and tell you anything, believing that the opinion they have is correct when it is not always the case.

Thank you again.

Happy DX-ing and Best 73 de Dave VK5FDMR
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AD5X
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Posts: 1626




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« Reply #6 on: July 26, 2007, 05:00:18 AM »

I had an Outbacker a bunch of years ago that
I picked up extremely cheap at a hamfest.  The guy who sold it to me said he could never get it to work.  As I recall (and I'm not sure), it turns out that he was winding the wander-lead in the same direction as the antena coil and that wouldn't work (antenna resonance was incorrect on any band he tried it on).  I wound the lead in the opposite direction and everything worked as it should.  Again, it has been awhile, so I might have this reversed.  But try it both ways and see what works (you do have access to an antenna analyzer I hope).

Phil - AD5X
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AA4PB
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« Reply #7 on: July 26, 2007, 05:50:27 PM »

I find it rather odd that the direction makes any difference because the wander lead shorts out the part of the loading coil that it is wound around.
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Bob  AA4PB
Garrisonville, VA
K3AN
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Posts: 787




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« Reply #8 on: July 29, 2007, 11:08:47 AM »

Whoa. The questioner is a VK5 who lives in the SOUTHERN hemisphere. Wouldn't he need to wind his coils in the reverse direction from how we wind them here?   ;-)

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N1LO
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« Reply #9 on: July 31, 2007, 06:06:43 AM »

I have experimented extensively with air-core coils in homebrew bugcather designs. Winding the wander lead, or jumper as I call it, in the same direction as the coil turns, provides the most consistent results in predisting which coil turn will provide resonance. Choosing a tap point that causes the jumper to be in the opposite direction will cause a discontinuity, but as long as you find a tap point that resonates the antenna, and are consistent in dressing the jumper, both methods will work.

--...MARK_N1LO...--
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