Sidebar Sidebar
  • You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

Son of a Gunn

eddie,
im going by the physical size of it for a 10mtr antenna, i would say the bottom of the radiator is where the coax braid bolts but that may not be where jogun measure it from,
oddly jogunn do not give other lengths for the 26-29.5mhz they say it covers, the instructions say adjust the tapping point then fine tune with the capacitor,
i found while playing with sigma style antennas and gamma fed scaffold poles that the gamma can make a vswr meter happy over a fairly wide range of monopole lengths.
 
Antenna Debates can often become heated, that is to be expected.
Nothing wrong with a good debate.
I have cleaned the thread a bit, and ask respectably that we move along and stay on topic....If someone has a disagreement, by all means you are welcome to present each side with out adding any lamp oil to the thread.

Carry on Gentleman.

73
Jeff
 
bob85 said:
robb,
the son of a gunn is a 3/4wave groundplane, low impedance at the base, the gamma strap is tapped up the vertical to find 50ohms then the cap is adjusted to cancel the reactance,
a 5/8wave has relatively high end impedance, adjusting the gamma capacitor can only tune out reactance, it can't change the real part of the resistance.
Click to expand...

Well Bob, you knew that I was going to model the JGSOG as you suggested, at 26' from somewhere logical I guess. But who knows? I just made the radiator part 26' feet like you suggested. I did the same setup with a 5/8 wave radiator at 22.5' feet...so we can compare.

We've argued this point about a 3/4 wave ground plane before, and we base our idea on the conclusion the S4 is not a ground plane. So we tend to feel comfortable with the idea as to why this 3/4 wave S4 works well...in spite of the rule...that a 3/4 wave ground plane is considered worthless.

Have you changed you mind on this, considering your claim that the JG is a 3/4 ground plane?

I've hear plenty of complaints that the JG is hard to tune, and MC saying it is constructed using wood screws, but I've never heard anyone say it was a 3/4 wave, and that it didn't work well.

I named my files for this project FreeCell..etc., because in my checking things out I did a WWRF search, and found and old thread where we discussed the JG, among other things. After reading, I planned to address the conclusions that FC made back then...before I could use Eznec.

Here are two models with the same exact basic design. The only difference is the length of the radiator, wire #9. One is my impression for your idea that the JG is a 3/4 wave at 26', and the other is 5/8 wave at 22.5' feet. Both antennas are mounted at 36' with a mast attached. The JO stands to be corrected if better dimensions turn up.

View attachment Bob's idea JGSOG is a .75 wave..pdf
 
Eddie, In that post M/C also stated that it was a 26` antenna, and this is from the Joe Gunn Web site:

JGAR - SON OF A GUNN (VERTICAL) ANTENNA
( Jo Gunn Enterprises, LLC )
Price: $419.00

(FREQUENCY RANGE: 26.000 - 29.500)

GAIN: 7.75 DB
MULTIPLICATION FACTOR: 19X
POWER RATING: 2000CW. 4000 PEP
WEIGHT: 14 lbs.
LENGTH: 26 feet
MATERIALS: 6063T-6 Aircraft Aluminum Tubing
REQUIRES 1 COAXIAL CABLE FOR HOOK-UP


Note the 7.75 DB gain figure........just about inline with the 4.75 DB gain of the Hillbilly antenna that is only 11 feet tall.
Now I have no idea if that measurement is total length....Bottom of radials to tip of antenna, or bottom of mounting bracket...or??

These figures can be seen Here:

www.jogunn.com - JGAR - SON OF A GUNN (VERTICAL) ANTENNA

www.jogunn.com - JGAR - HILLBILLY (HORIZONTAL - VERTICAL) ANTENNA

73
Jeff
 
eddie,
mc posted pictures of the son of a gun stripped down, the box section did not look very long so the radiator is electrically closer to 3/4wave on 10mtrs than it is 5/8wave even if they are measuring the 26ft from the bottom of the box section,
mc said the jogunn was a little shorter than the sigma4 and could be a true 3/4wave, i trust him to know when a groudplane is longer than a 5/8wave even though he lacked the strength to pull his tape measure out past 1/2wave,

i would expect the jogunn to make high angle lobes compared to a 5/8wave if used as supplied on 10mtrs.


i remember reading something on the www that said you can shorten the radiator from resonance needing less cap in the gamma but going too short caused high circulating currents in the gamma section, i don't recall exactly what the article said..
 
bob85 said:
eddie,
mc posted pictures of the son of a gun stripped down, the box section did not look very long so the radiator is electrically closer to 3/4wave on 10mtrs than it is 5/8wave even if they are measuring the 26ft from the bottom of the box section, mc said the jogunn was a little shorter than the sigma4 and could be a true 3/4wave, i trust him to know when a groudplane is longer than a 5/8wave even though he lacked the strength to pull his tape measure out past 1/2wave,

i would expect the jogunn to make high angle lobes compared to a 5/8wave if used as supplied on 10mtrs.

i remember reading something on the www that said you can shorten the radiator from resonance needing less cap in the gamma but going too short caused high circulating currents in the gamma section, i don't recall exactly what the article said..
Click to expand...

Bob, my buddy close to my house has one, but doesn't recall the length. Unless they are modified to be adjustable all the way up, only the tip is adjustable for length. The antenna is held together by screws or bolts, and the length is fixed for that portion.

Believe me I didn't spend any time modeling the JG. With less that good numbers, what's the point. That is why I made it like I did, just to show what everybody that I've ever heard talk on the subject, saying a 3/4 wavelength radiator with a ground plane radiates like a long wire, and all the signal goes almost straight up. It's either true or it's not. The model surely shows it is true, that a 5/8 wave will work well to a point, but a 3/4 wave ain't so good.

I'm probably wrong, because I never knew it was that long, and if it is, them my modeling ain't worth a hoot, or the claims over the years about 3/4 radiators is all hog wash. You tell me that you can and have tuned scaffolding poles of different lengths over a moderate range using a gamma. Did they work as you would expect, showing a maximum low angle, or could you tell? Maybe the old 3/4 rule is just more CBBS, because I can tell by my neighbor's JG it works very well. He is the one I told you about that threw away two Vector 4000, because he prefers the JG.

There are several around me and I'll ask around and see if there still up. The word is the JGSOG works very well, so I just assumed that it was a long 5/8 wave, but I didn't know it was 26' feet.

Did MC, show you the secret mystery construction inside of the base he talked about? I don't recall seeing any pictures either. Do you know where they are?

Thanks Jeff, I saw that claim by MC when I searched the topic and found the old thread. I guess that is where Bob got his idea about it being a 3/4 wave.

I also just posted another thread on the subject with a view from what my Eznec shows. That is why I named the models Freecell...etc, based on the thread.

Maybe I should have entitled it Master Chief instead.
 
i can't find anything more than what's on jogunn's site about tuning, no mention of altering the length at all for different frequencies,
what is good for 26mhz is good for 29.5mhz with a tweak of the gamma according to the instructions,
i have see one guy claim his gunn is 28ft,
the way i see it is its very likely 24ft+ of radiator which is a long 5/8wave @29mhz,
the only way to know the length for sure is measure one that has not been messed with, then maybe model it on 29.5 and 26mhz,

gamma fed scaffold poles about 3/4wave work but not nearly as good as a similar length sigma4 in the same mounting position,

everything i have read says that going longer than .64-5/8wave causes high angle lobes to form at the expense of low angle radiation, your 26ft model looks to be inline with what i have read,

i don't think there were any secrets in the base, if you read his later description its tripple walled tube, everything grounded like a sigma4 with the radials folded down,

we don't know how your buddy has his gunn set up, also take into account you don't see much difference between any two antennas in your area like some of us do,

jogunn antennas look pretty well made, 6063-t6, not the best tube ever used in cb antennas as they claim, not even the second best but it looks and feels heavy duty compared to the vector 4000 tubing,
several locals have bought vectors then bailed out when they assembled them and realized what 30ft of flacid aluminum looks & feels like.
 
Last edited:
my antron still out talks it,,I got the swrs down to 1.6 I could give a Great testamonial For solarcon...THANKS AGAIN....LEE
Click to expand...

Lee, when you say that the Antron out talks the Jo Gunn, can you tell us what the details are?
Is it local contacts?
Also what is your operating conditions...what I am asking is, how high do you have it mounted, and what kind of terrain do you have around you.
A .75 antenna, as Eddie`s modeling show`s has a high TOA I can see how the Antron may show a better signal to other stations close in to you as the lobe with the highest gain is overshooting them.


73
Jeff
 
Robb said:
www.jogunn.com - JGAR - SON OF A GUNN (VERTICAL) ANTENNA

WOW!
This silly thing sells for $419 list price! For that much money, one can buy a lot of antenna. Not sure this antenna qualifies for that - IMO. Never hear any glowing reviews of it anywhere. In fact, no reviews that I can find at all for that matter.

3.2 points given out of a possible 5 points on eHam doesn't exactly indicate a 'glowing report' - IMO . . .
http://www.eham.net/reviews/detail/6840
Click to expand...

Yep Robb, the JG is lots of money and it always has been. This is why I suspect that much of the words we hear regarding JG ownership from CB'rs has been CBBS...guys wanting one and talking it up with a lots of Wolf talk. I think most of the JG crowd are the power hungry types, so no tellin' what your likely to hear from them.

On the low power side of the ledger, I remember long ago, Wilbur my neighbor with the JGSOG, telling me that my Starduster signal was way down compared to others in this immediate area. I also recall being able to hear stuff sometimes that these guys said they couldn't hear. So, I said it must be the SD'r, but I wasn't sure.

Later on I took the antenna down, and found out I had water in my old second hand Mini8 coax, and it had been there a long time. Long enough to turn the shield black and green in spots along its 100' length. So, sometimes we might not know what's really going on with our antenna systems.
 
bob85 said:
i can't find anything more than what's on jogunn's site about tuning, no mention of altering the length at all for different frequencies, what is good for 26mhz is good for 29.5mhz with a tweak of the gamma according to the instructions,
Click to expand...

I was wrong Bob, the tip is NOT adjustable. Looking at the antenna image in the manual, it shows a screw is securing the tip element also. So, it looks like the whole antenna is fixed, and your right the frequency is adjustable via the gamma dog bone first at 43" from the top on the base element, then some fine tune adjustment can be made with the gamma stinger, but a caution says, "...do not reverse this process."

Boy, I understand now why guys have trouble with this antenna. They are using a pig tail stub connection, and that makes checking the SWR at the feed point impossible without a jumper or feed line, both of which can cause transformation if the load is not already near perfect at the desired frequency of operations. This says nothing about raising the antenna and seeing the match change due to height. This one might take a highwire act to tune.

You are right Bob, the JGSOG is intended to tune within the range given, 26.000 - 29.500 mhz, using the gamma adjustments only. So, in order to determine the length for this antenna for modeling purposes, one would have to get the specific length from JG and how it was measured. Or use a perfectly stock antenna from JG, assembled and measured between two specific points. We know for sure one point is the tip.

bob85 said:
i have see one guy claim his gunn is 28ft, the way i see it is its very likely 24ft+ of radiator which is a long 5/8wave @29mhz, the only way to know the length for sure is measure one that has not been messed with, then maybe model it on 29.5 and 26mhz,
Click to expand...

You're right again, we need to know the antenna is unmodified, and where the bottom is measured from, just like you state.

bob85 said:
gamma fed scaffold poles about 3/4wave work but not nearly as good as a similar length sigma4 in the same mounting position,

everything i have read says that going longer than .64-5/8wave causes high angle lobes to form at the expense of low angle radiation, your 26ft model looks to be inline with what i have read,
Click to expand...

So, this may mean the old 3/4 wave idea is still valid, right?

bob85 said:
i don't think there were any secrets in the base, if you read his later description its tripple walled tube, everything grounded like a sigma4 with the radials folded down,
Click to expand...

I didn't think so either.

bob85 said:
we don't know how your buddy has his gunn set up, also take into account you don't see much difference between any two antennas in your area like some of us do,
Click to expand...

I agree, but if you're right and this antenna is that much longer than a 5/8 wave of about 22.5' feet, then what about the 3/4 wave rule? My model doesn't seem to suggest that this particular radial design fixes the 3/4 issue like happens with the Sigma4. Maybe I'll have to fix the radials on my JG to fully horizontal, and see what the difference is.

bob85 said:
jogunn antennas look pretty well made, 6063-t6, not the best tube ever used in cb antennas as they claim, not even the second best but it looks and feels heavy duty compared to the vector 4000 tubing, several locals have bought vectors then bailed out when they assembled them and realized what 30ft of flacid aluminum looks & feels like.
Click to expand...

My buddies SOG was mounted on a 25' foot tower and went through hurricane Ike, when it came thru the Houston area in 2008. It was bent a little, but still working. I took all of my stuff down.
 
eddie,
i don't think there is much wrong with your 3/4wave rule idea, its what smart folk tell us happens when you extend a single element over 5/8wave,

i doubt raising the radials to 90 degrees will fix it but if you fold them up to say 30 degrees from vertical you may see an improvement.
 
  • Like
Reactions: 2 people
I agree with Duster AVOID this antenna,And in response to the other comment yes Power hungery does describe operators in this area including me,I just want to be loud local so i should reverse the angle of the ground plane elements to have a low angle of radiation for local contacts?? Once again thanks 4 all the help...
 

dxChat
Help Users
  • No one is chatting at the moment.


      Top Bottom
      Back