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Jo-Gunn 5 or 6 Star
- Thread starter Green Tiger
- Start date
Save your time and money with the Jo-Gunn and just buy or build a Maco dual polarity beam. Regardless of what the cost of the Jo-Gunn might have you think about its performance, they have no advantage at all in terms of performance. Nothing but a gimmick that allowed them to use 25% less tubing while charging 50% more money.
JO-GUNN.
If you over look all the advertising bull SH*T they have, the false claims they make of gain, etc,etc, Enough said about the lies and crap they try to sell.
The yagi is built like a brick sh*house. Solid, Thick walled construction.
I also like how they use 25% less metal eliminating the bottom elements.
Now you do not need a 20' piece of mast pipe to stick up out of the tower, 5' works great. No bottom element to clear.
If you live in a very, very windy or a QTH that has a lot of snow and ice then sure spend the money buy your JO-GUNN.
You could home brew a better yagi with better performance.
As far as original question? I have not seen a site that gives the instruction manual for jo gunns. It is not rocket science to build a yagi, just use the old Avanti moonraker four dimensions, or moonraker 6 dimensions and add 5% in length to the reflector so you can use regular elements and not the quad type wire reflector.
Good luck and have fun.
If you over look all the advertising bull SH*T they have, the false claims they make of gain, etc,etc, Enough said about the lies and crap they try to sell.
The yagi is built like a brick sh*house. Solid, Thick walled construction.
I also like how they use 25% less metal eliminating the bottom elements.
Now you do not need a 20' piece of mast pipe to stick up out of the tower, 5' works great. No bottom element to clear.
If you live in a very, very windy or a QTH that has a lot of snow and ice then sure spend the money buy your JO-GUNN.
You could home brew a better yagi with better performance.
As far as original question? I have not seen a site that gives the instruction manual for jo gunns. It is not rocket science to build a yagi, just use the old Avanti moonraker four dimensions, or moonraker 6 dimensions and add 5% in length to the reflector so you can use regular elements and not the quad type wire reflector.
Good luck and have fun.
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I think my biggest complaint about this style antenna is that even though it has two feedlines, it has no horizontal polarization and only half a vertical antenna. By placing the elements on a 45 degree angle and eliminating the bottom vertical element, the antenna has given you 3 db less gain in either polarization to any other vertical or horizontal polarized signal. Then if you phase the two coaxes together to try and cover two opposing polarities or run circular polarization, there goes another 3 db.
Another huge issue is there is almost no rejection to local vertical signals when working the horizontal side. When the elements are orientated so they are turned 90 degrees apart, you get about 20 db of isolation between the two. When the elements are on a 45, you get very little isolation and a 3 db drop to both vertical and horizontal signals. Not what I want to spent my money on. Why pay more for less? The only thing it has going for it is mechanical construction. In my eyes that just means you'll be stuck with the piece of junk for a long time.
Another huge issue is there is almost no rejection to local vertical signals when working the horizontal side. When the elements are orientated so they are turned 90 degrees apart, you get about 20 db of isolation between the two. When the elements are on a 45, you get very little isolation and a 3 db drop to both vertical and horizontal signals. Not what I want to spent my money on. Why pay more for less? The only thing it has going for it is mechanical construction. In my eyes that just means you'll be stuck with the piece of junk for a long time.
as said before if you live where you have really strong winds and harsh weather patterns get the Jo-gunn but go with the conventional series the tradiotional Yagi designs. they still offer a dual polarity type antenna in the yagi pattern. boom lengths are to short for the gain they advertise but they do work decent.
hello greentiger . dont listen to this nonsence . there is nothing wrong with a Jo Gun Beam at all !!!!!!!! there is awsome technology in that Beam !!!!!! you put a jo gun beam up and it will not fall down . you put a maco beam up , lol lol lol and bye bye bye bye in the wind it will fly like a kite when you get a 75 mph wind storm . the gain on a jo gun beam is amazing and they out perform alot of antenna's out there .
HMMM, with a statement like that makes me curious as to how many times you missed physics 101 class?
A vendor can claim anything, back it up with the math if they want to prove it, numbers do not lie.
Shockwave,
I built a home brew four element jo-gunn copy, on a 17' boom so I can not honestly say it is jo gunn but it is the one vertical and two horizontal bent elements so in theory basically the same type but different spacing and boom length.
I did notice only about 15db of difference between vertical and horizontal pols, but there is a difference.
The F/B was pretty good but I will give that to the boom length and spacing of elements.
It was an experiment, it works, not great, but it does work.
I would not spend any money to buy a jo gunn.
I built a home brew four element jo-gunn copy, on a 17' boom so I can not honestly say it is jo gunn but it is the one vertical and two horizontal bent elements so in theory basically the same type but different spacing and boom length.
I did notice only about 15db of difference between vertical and horizontal pols, but there is a difference.
The F/B was pretty good but I will give that to the boom length and spacing of elements.
It was an experiment, it works, not great, but it does work.
I would not spend any money to buy a jo gunn.
Wavrider, thanks for sharing your experiment. The front to back ratio is as I expected with this design. Not impacted because that is a function of element length, spacing, and boom length. They got that part right. The problem is it falls short of every other less expensive antenna when it comes to forward gain and separation. Your separation was better than expected but still 5 db less than any other dual feed antenna.
High Voltage, If you're going to imply you have a deep enough understanding of this design that GreenTiger can ignore all the good advice he's been given here, please enlighten us with more than vague opinion. Reasons hold more water than opinion. For example, when you remove 50% of the vertical element it's not possible to have any other result than a loss in gain. When you put your horizontal elements 45 degrees away from horizontal, you're at a disadvantage to any linear polarized horizontal signal. One can debate the degree of loss but not the fact there has been loss.
I installed a M-104 with a fairly heavy "T" match network loading down both sides of the driven element. We just had several hours of gusts to 90 MPH on the coast of Connecticut with hurricane Sandy. The 5/8 wave S-2016 folded over a 10 foot section of heavy wall fence pipe like it was nothing. That antenna survived but it's now horizontal. The modified M-104 on the tower never gave any sign of being over stressed even at the height of the storm.
High Voltage, If you're going to imply you have a deep enough understanding of this design that GreenTiger can ignore all the good advice he's been given here, please enlighten us with more than vague opinion. Reasons hold more water than opinion. For example, when you remove 50% of the vertical element it's not possible to have any other result than a loss in gain. When you put your horizontal elements 45 degrees away from horizontal, you're at a disadvantage to any linear polarized horizontal signal. One can debate the degree of loss but not the fact there has been loss.
I installed a M-104 with a fairly heavy "T" match network loading down both sides of the driven element. We just had several hours of gusts to 90 MPH on the coast of Connecticut with hurricane Sandy. The 5/8 wave S-2016 folded over a 10 foot section of heavy wall fence pipe like it was nothing. That antenna survived but it's now horizontal. The modified M-104 on the tower never gave any sign of being over stressed even at the height of the storm.
HV, do you have the dimensions for a JG or a manual with dimensions. I would like to model a 3 or 4 element model.
I would be interested in seeing the results of some modeling on this too. I suspect it will show no advantage in gain when compared to any other Yagi on the same boom. The problem will be in identifying the disadvantage related to various degrees of cross polarization. Bending the elements on a 45 degree angle will have little impact on the actual gain. The 3db loss is not related to antenna gain but to the fact none of the horizontal elements are horizontal and only half of the vertical element is vertical.
Anyone who has experimented with rolling the boom of a Yagi during signal testing can confirm as soon as you reach the point where you are 45 degrees away from matching the polarization of the opposite station, you lose 3db to them. Continue to cross polarize further and the loss in gain goes up exponentially until you are 90 degrees out of polarization with a peak loss of 20db.
My point here is EZNEC will have to identify the gain in a given plane, either horizontal or vertical to spot this loss since it's not related to the elements. It's mostly their orientation responsible for the loss in gain. Although, two stations both working this antenna would not see a signal loss due to cross polarization. Also the effect is less noticeable in DX because once the signal reflects off the ionosphere, polarization will shift anyhow. Still, why pay more for less just because the manufacturer tells a bigger lie?
Anyone who has experimented with rolling the boom of a Yagi during signal testing can confirm as soon as you reach the point where you are 45 degrees away from matching the polarization of the opposite station, you lose 3db to them. Continue to cross polarize further and the loss in gain goes up exponentially until you are 90 degrees out of polarization with a peak loss of 20db.
My point here is EZNEC will have to identify the gain in a given plane, either horizontal or vertical to spot this loss since it's not related to the elements. It's mostly their orientation responsible for the loss in gain. Although, two stations both working this antenna would not see a signal loss due to cross polarization. Also the effect is less noticeable in DX because once the signal reflects off the ionosphere, polarization will shift anyhow. Still, why pay more for less just because the manufacturer tells a bigger lie?
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