how effective is a j pole antenna on 11 meters ?

[BOOTY MONSTER]

homer i have no problem with any of my threads going off topic to help someone or any other useful discussion .

marconi , i dont have any empirical evidence that the sigma 4 and j pole are different designs of antenna .
i should know better than to just go by what someone else said

 

[HomerBB]

Thanks, Booty.
Careful, though, if ya said ya picked yer teeth Marconi'll want ya to produce yer pickin's for proof (and the toothpick).

s'a good thing I'm dumb and everybody knows it . . .

 

[BOOTY MONSTER]

i know youre just joking homer but i really do appreciate Marconi,s (and others) desire to separate truth from hearsay .

 

[HomerBB]

yeah, so do I.

 

[Boat Anchor 63]

I asked this on the QS site and got some replies, so here goes:

I understand that electrical lengths are not the same as physical lengths, however, with the supplied formula, this radiator works out to 25.93' (25' 11.2") in addition to a 20" apparently conducting piece beneath where the stub adjoins the main radial. The question that comes to mind is how an antenna of this length could possibly be classed in performance with an 18' half wave antenna? I'm having a hard time with that one.

Homer BB,
I read that a 11m j-pole vertical antenna can outperform Super Penatrator 500 and other 11m 5/8 wave antenna's if built correctly due to its length. What do you think?

 

[Captain Kilowatt]

A J-Pole is simply an end fed stub matched HALF WAVE radiator. Nothing mystical nor magical about it. Performance is on par with any other radial-less halfwave vertical. The angle of radiation could be lower if radials were used but that applies to any vertical whether it "needs" radials or not.

 

[HomerBB]

I don't think so. The Jpole is a 1/2 wave antenna. The bottom part that gives it the J shape is actually a U shape and is a 1/4 wave matching section. What you have is a 1/2 wave end fed antenna. In theory, the 5/8 should have more gain and lower radiation angle against the horizon. Many installations don't actually achieve any noticeable gain advantages with either antenna, but believe they have because of the improved angle of radiation toward signals they had not heard before.
As for how long the Jpole is, electrically it is the same length as a Ringo Ranger 1/2 wave. The Ringo just twist the matching section around the bottom of the antenna instead of up along one side.

 

[Boat Anchor 63]

I don't think so. The Jpole is a 1/2 wave antenna. The bottom part that gives it the J shape is actually a U shape and is a 1/4 wave matching section. What you have is a 1/2 wave end fed antenna. In theory, the 5/8 should have more gain and lower radiation angle against the horizon. Many installations don't actually achieve any noticeable gain advantages with either antenna, but believe they have because of the improved angle of radiation toward signals they had not heard before.
As for how long the Jpole is, electrically it is the same length as a Ringo Ranger 1/2 wave. The Ringo just twist the matching section around the bottom of the antenna instead of up along one side.

Homer BB,
I have been doing some research on the
11m j-pole vertical antenna and came across this information. Alot of operator's think a j-pole antenna can't compete with the likes of a
Sigma 4, I-10k, maco v-5000 etc.
I think if it was put on a test range against a few
5/8 waves side by side up at 40' to the base they we'll find out if it's any good or better.

 

[Captain Kilowatt]

Homer BB,
I have been doing some research on the
11m j-pole vertical antenna and came across this information. Alot of operator's think a j-pole antenna can't compete with the likes of a
Sigma 4, I-10k, maco v-5000 etc.
I think if it was put on a test range against a few
5/8 waves side by side up at 40' to the base they we'll find out if it's any good or better.

One common mistake most of these reviewers do is try one antenna for a while then take it down and try another. You cannot do that. BOTH antennas need to in use and the same time and isolated from each other and then switch between the two. Signals can change from hour to hour even on local contacts by enough to render any perceived differences null and void.

 

[Boat Anchor 63]

One common mistake most of these reviewers do is try one antenna for a while then take it down and try another. You cannot do that. BOTH antennas need to in use and the same time and isolated from each other and then switch between the two. Signals can change from hour to hour even on local contacts by enough to render any perceived differences null and void.

Captain Kilowatt,
I have tested alot of antenna's which depends on the operator's location.
11m 1/4 wave vs 1/2 wave vs 5/8 wave vs
3/4 wave vs full wave vs 1.25 wave vertical antenna angle of radiation toward to horizon is different if you live in areas surrounded by mountain's, tall building's etc.
Sometimes the 1/4 wave when propagation conditions are good can outperform any other vertical antenna due it's height above ground.
Sometimes the other antenna's can due the same it all depends how the ionosphere is working that day via groundwave or skywave.
That's why alot of operator's have an antenna farm with multiple antenna's placed at different heights above ground.
If properly built there can be one antenna that can outperform all of the other's that can transmit vertical during groundwave propagation you and horizontal during skywave propagation.
It all depends on what your looking to do.

 

[HomerBB]

You can count on one thing where monopole antennas are concerned, you just never know from one day to another and one install to another what's going to happen.
I've many, many times had my mobile antenna so short and so near to the ground outperform my base antenna. Conditions.
Never surprised by someone's claimed experience.

 

[freecell]

when was the last time you remember anyone stateside bragging about working australia or europe on 11 meters using a j-pole?

 

[Boat Anchor 63]

when was the last time you remember anyone stateside bragging about working australia or europe on 11 meters using a j-pole?

Freecell,
When I was stationed at Fort Denvens in Massachusetts back in 1985 I had a qso on a RadioShack Realistic Trc-440 with a operator in Baton Rudge, LA after loading up my balcony railing with a 9' piece of rg8x coaxial cable on 27.205mHz. He said I was giving him a
S10 over 9. The same evening I again had a qso with a operator in Hawaii with the same setup.
He said I was 5by7. So if propagation conditions are right anything is possible.
I just built a 11m j-pole/slim jim and only thing I have to do is put them up my my test pole and check there standing wave ratio which I hope is under 1.5.

 

[Captain Kilowatt]

Years ago I had a QSO with Florida using an indoor dipole in my BASEMENT. Doesn't mean the antenna was any good. It just meant I got lucky. Just like the time I worked 3BC9 on Rodrigues Island in the Indian Ocean via longpath one morning on 20m. 100 watts into a Hamstick while driving to work. Longpath was 15,000 miles. It is virtually impossible to judge an antenna by how it performs on DX and especially when based on only a few contacts.

 

[Boat Anchor 63]

Years ago I had a QSO with Florida using an indoor dipole in my BASEMENT. Doesn't mean the antenna was any good. It just meant I got lucky. Just like the time I worked 3BC9 on Rodrigues Island in the Indian Ocean via longpath one morning on 20m. 100 watts into a Hamstick while driving to work. Longpath was 15,000 miles. It is virtually impossible to judge an antenna by how it performs on DX and especially when based on only a few contacts.

Captain Kilowatt,
That's correct all we can do is be great full.
I love building antenna's and having the ability to switch between them for the best conditions is what it's all about. Right now I am going to focus on my 11m j-pole/slim jim. There are so many different formulas on building them its mind boggling but I think I might have stumbled upon one that works for my location. Will post my findings soon.
Every one have a happy 4th of July 2021.