Questions tagged [j-pole]
The j-pole tag has no usage guidance.
13
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6
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Why don't J-Poles need to be grounded?
I'm building my first J-Pole and the different projects and articles I read about differ slightly but one commonility is a J-Pole does not need to be grounded. Why is that?
I read that it is optional ...
- 309
3
votes
2
answers
126
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Will spray painting a J-pole impede functionality? [duplicate]
I'm building a J-pole antenna like the one specified here: https://www.sysjolt.com/2022/building-a-j-pole
As you can see it's made of copper pipe and I'd like to camouflage the antennae a little bit.
...
- 309
3
votes
1
answer
297
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Phasing stub length for colinear 5/8λ?
I've been designing a "Super J-Pole" for 10M in MMANA-GAL, but I'm designing it having two 5/8λ sections. However, I came across this picture: Various J-Poles types diagram indicating the ...
- 727
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2
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Generally speaking what might one expect from a J-pole based on PVC covered in tinned braid? [closed]
Would the skin effect provide benefits or would capacitance/inductance cause problems?
- 363
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0
answers
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J Pole, what is the best way to deal with Common Mode Current? [duplicate]
I am planning on utilising a ferrite choke on a J Pole antenna for CMC. Placement directly on the feedpoint poses possible mechanical restraints. Is it okay to place it a quarter wave down the coaxial ...
4
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1
answer
1k
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How do dual band J poles work?
My understanding is a J pole is a $\frac{1}{2} \lambda$ dipole attached to a $\frac{1}{4} \lambda$ impedance matching element.
How does this dual band work? What acts as the impedance matching element ...
- 257
4
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4
answers
3k
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Is a copper J-Pole antenna better than a Slim Jim for transmitting?
I live in a fairly sheltered valley but there are several hill-top VHF repeaters that I can receive very well. However the one repeater in particular I want to transmit to, I can't reach well. I ...
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3
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3
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Mounting a J-Pole and Yagi on the same mast
I have two 2-meter antennas, a copper J-Pole and a Hy-Gain VB-25FM. The J-Pole is my all-around antenna, what I use for general 2 meter stuff like connecting to my local repeaters using my main 2-...
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3
votes
1
answer
902
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Is a J-pole an appropriate antenna for mounting to a steel handrail?
Last year, a group of us placed a battery-powered 2m digipeater using a J-pole antenna on a mountaintop. We're planning on doing the same this year except we plan to use a surge arrestor from the feed ...
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2
votes
2
answers
499
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baofeng UV-5RA has issues with j-pole
I have a baofeng UV-5RA which doesn't seem to receive properly with my j-pole antenna. my dad's radio (same model, different firmware) receives without a problem, so it's a radio issue. if I go into ...
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6
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1
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16k
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How to calculate single-stub match (general case)?
I'm trying to build a 1/2 wave "Coaxial J-Pole" antenna, similar to what is described here:
Such an antenna would be great for stringing up in a tree when operating remotely, no tuner needed.
The ...
1
vote
2
answers
491
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Measured forward power less than "usual"
I've just tried making my own J pole antenna. While matching for lowest SWR on the SWR meter, I noticed that my FTM400 didn't show 5 W forward power.
I hardly saw the reflected power needle move so I ...
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8
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3
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873
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How would I calculate antenna gain?
The concept of antenna gain is pretty important for calculation of link budget and is something I've had contact with. I know that it tells me how focused the waves emitted by the antenna are and I ...
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