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Wire length question


Howard E. Mahran / WA1HEM
 

I realize this might be a silly question and the significance to the overall wire length minimal but the question is burning a hole in my head: Do you count the part of the wire that is tied around the ceramic insulator when measuring wire length ?  I say “yes”


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Howard E. Mahran
WA1HEM
(425) 864 - 5104
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Jackson Beard
 

I think yes is sort of correct. Some of the knot is not an effective radiator. 

The real question is does it matter. I don't think so. 

On Sat, Jul 11, 2020, 22:04 Howard E. Mahran / WA1HEM <wa1hem@...> wrote:

I realize this might be a silly question and the significance to the overall wire length minimal but the question is burning a hole in my head: Do you count the part of the wire that is tied around the ceramic insulator when measuring wire length ?  I say “yes”


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Howard E. Mahran
WA1HEM
(425) 864 - 5104
*************************


Dan Pflugrath
 

I have always measured to where the wire goes through the insulator.  In the real world unless you have some very accurate test equipment you will never know the difference in resonant frequency between up to the insulator and where the wire goes through the insulator..Even if the 1/2 inch changed the SWR by 0.5 you or the other station would not hear a difference.


Paul Zoba
 

I’m no expert but as I’ve played around with wire antennas, and reading ARRL publications, I believe any folded over length of wire is not counted. What matters is end to end reach of the conductor. The part wrapped around or folded back is not counted. 

I do agree with Dan, the performance difference either way will be insignificant.


On Jul 11, 2020, at 10:04 PM, Howard E. Mahran / WA1HEM <wa1hem@...> wrote:



I realize this might be a silly question and the significance to the overall wire length minimal but the question is burning a hole in my head: Do you count the part of the wire that is tied around the ceramic insulator when measuring wire length ?  I say “yes”

<08C416AD-97C7-4404-877F-0AA41B5874B1.jpeg>

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Howard E. Mahran
WA1HEM
(425) 864 - 5104
*************************


Paul Butzi (W7PFB)
 

Apparently everyone else in SnoVARC either stays up later than I do or gets up earlier.

I vote with Dan - measure to the hole in the insulator.  Any place where the wire is wrapped around itself, the effect is that doubled over portion does not contribute to the effective length.  On the scale of any HF antenna the loop going thru the insulator is the same as a wire just reaching the eye of the insulator.

And I also vote with everyone who says it doesn’t matter.  You won’t know the velocity factor of the wire to better than, say, 2%, and that source of uncertainty alone means you’re going to end up tweaking the length using your handy antenna analyzer.

-p W7PFB
73, Don’t forget to smile and have fun!

On Jul 11, 2020, at 10:04 PM, Howard E. Mahran / WA1HEM <wa1hem@...> wrote:

I realize this might be a silly question and the significance to the overall wire length minimal but the question is burning a hole in my head: Do you count the part of the wire that is tied around the ceramic insulator when measuring wire length ?  I say “yes”

<08C416AD-97C7-4404-877F-0AA41B5874B1.jpeg>
--
*************************
Howard E. Mahran
WA1HEM
(425) 864 - 5104
*************************

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