I'm glad it was helpful. I have no idea how many have built a copy of this antenna but there have been quite a few that commented they have. It should serve you well as my first one (ll of them actually) is still in service and has seen some fairly rough use.
I'm going to build one of these. However, of all the DIY videos I have watched nobody talks about the minimum and/or maximum distance the curved sides of the rods can be from one another. This is baffling! If you place the two mounting points for the rods too close together isn't it possible you won't be able to adjust the SWR? The two ends will simply collide with each other. So how far apart should the mounting holes be from one another? Thank you! K9JPT
When I designed this antenna I used a "T" with 1" diameter on the "through" side and 3/4" diameter on the single leg (the one that points towards the junction box. This gave the best distance from bolt to bolt to allow for sliding the elements in and out for SWR adjustment without being too far apart. Just be sure not to put the bolts through the 1" "T" too close to the end (hence I reinforce them with either a plug or a short piece of pipe inside the ends of the "T" before drilling. In use, I've never had to do any adjusting. The elements are always pulled all the way out against the bolts and always give useable SWR across the band. If yo are trying to tweak in for absolute best SWR on a specific frequency, adjustment might influence things but it's generally not necessary. Hope that helps.
It works like a dream. I have gone 102 miles into a repeater with 50 watts from an altitude of just 12 feet above the ground. I've run fox hunts with 2 watts on a 12-15 foot mast. I've run long nets from the coast while it was set up on the back bumper of my 5th wheel RV.
Why not just repeat this design on the other end co-phasing the two for additional gain, plus if protecting the radiators from the elements why not just use smaller pipe and seal them inside, thus allowing the use of copper which radiates much better than any kind of steel? Good design, an I may build one except co-phasing for gain!
I think there may be some confusion. The elements don't go into the back part of the boom to protect them from the elements but rather to protect them from damage when transporting. The idea being that you could break down the antenna and not end up with bent elements. In practice, I've found that just folding them back along the offset from the mast protects them sufficiently. I have considered the potential for a phased array as well as just putting a reflector (2 element beam) but this antenna has cone 102 miles into a repeater at just 12 feet of height with 50 watts. While a beam design would reduce the necessary power for that operation, it's overkill for my purposes and would remove the omni directional properties.
The final result of the antenna without the choke is that it works quite well and I've built a number of them as have other HAMS with nothing but good results.
@@kg7tuo999 So I am a little confused. There is a short side and a long side on each element. I am only seeing one length given. Is it the shot or long side and what is the length of the second side. Sorry if this does not make sense.
I built a 6 meter from PVC pipe (the boom), snap on T's, and bungee corded aluminum tent poles. I designed it on NEC and built it as a 4 element Yagi that folds up and fits in the bed of my truck. It works on 440, 2m, and 6m. The proof of concept is built and has been used in the field. I'll next build one without the snap T's (used to be able to adjust elements but none was needed) and a bit more attention to the fold up process to make it even better in the field. Not sure if that will come before or after I try to a 2 element 20m from PVC and tent poles (with a non tent pole center portion of the elements)
Watched all 4. Enjoyed, thx
I built this antenna. Works great and portable! Thanks for the videos!
I'm glad it was helpful. I have no idea how many have built a copy of this antenna but there have been quite a few that commented they have.
It should serve you well as my first one (ll of them actually) is still in service and has seen some fairly rough use.
Wonderfull videos, thanks for this.....wonder if It's still up and working :)
OUTSTANDING work,well done.
Ohhh Rahhh, Jarhead. Semper Fi.
I'm going to build one of these. However, of all the DIY videos I have watched nobody talks about the minimum and/or maximum distance the curved sides of the rods can be from one another. This is baffling! If you place the two mounting points for the rods too close together isn't it possible you won't be able to adjust the SWR? The two ends will simply collide with each other. So how far apart should the mounting holes be from one another? Thank you! K9JPT
When I designed this antenna I used a "T" with 1" diameter on the "through" side and 3/4" diameter on the single leg (the one that points towards the junction box. This gave the best distance from bolt to bolt to allow for sliding the elements in and out for SWR adjustment without being too far apart. Just be sure not to put the bolts through the 1" "T" too close to the end (hence I reinforce them with either a plug or a short piece of pipe inside the ends of the "T" before drilling.
In use, I've never had to do any adjusting. The elements are always pulled all the way out against the bolts and always give useable SWR across the band. If yo are trying to tweak in for absolute best SWR on a specific frequency, adjustment might influence things but it's generally not necessary.
Hope that helps.
The lengths, measured from the outside of the bottom bend, are:
6 1/4" for the 70cm side
18 5/8" for the 2m side
saludos aunque un poco lento el vídeo me gusto, y aprendí algo nuevo TKS 73
ok so does it work ?
It works like a dream. I have gone 102 miles into a repeater with 50 watts from an altitude of just 12 feet above the ground. I've run fox hunts with 2 watts on a 12-15 foot mast.
I've run long nets from the coast while it was set up on the back bumper of my 5th wheel RV.
Which with the measurements in cm please?
I don't have those handy. Any online conversion calculator can give you the converted measurements.
Why not just repeat this design on the other end co-phasing the two for additional gain, plus if protecting the radiators from the elements why not just use smaller pipe and seal them inside, thus allowing the use of copper which radiates much better than any kind of steel? Good design, an I may build one except co-phasing for gain!
I think there may be some confusion. The elements don't go into the back part of the boom to protect them from the elements but rather to protect them from damage when transporting. The idea being that you could break down the antenna and not end up with bent elements. In practice, I've found that just folding them back along the offset from the mast protects them sufficiently.
I have considered the potential for a phased array as well as just putting a reflector (2 element beam) but this antenna has cone 102 miles into a repeater at just 12 feet of height with 50 watts. While a beam design would reduce the necessary power for that operation, it's overkill for my purposes and would remove the omni directional properties.
@@kg7tuo999 I was thinking more in terms of the antenna being mounted a home install, instead of portable. Still a good build and good project.
Yes
What was the final result of the antenna?
The final result of the antenna without the choke is that it works quite well and I've built a number of them as have other HAMS with nothing but good results.
Now I am con fused,,,the copper J pole is a dead short of the leads,, yours is open......
This is basically a dipole antenna oriented vertically for FM operation on 2m/440. The J Pole uses different principles than a dipole.
So what are the actual lengths you cut the elements to?
The lengths are in the description for the vid.
@@kg7tuo999 So I am a little confused. There is a short side and a long side on each element. I am only seeing one length given. Is it the shot or long side and what is the length of the second side. Sorry if this does not make sense.
@@bulldude56 The lengths, measured from the outside of the bottom bend, are:
6 1/4" for the 70cm side
18 5/8" for the 2m side
Instead of a counter weight a 6 meter would be nice.
I built a 6 meter from PVC pipe (the boom), snap on T's, and bungee corded aluminum tent poles. I designed it on NEC and built it as a 4 element Yagi that folds up and fits in the bed of my truck. It works on 440, 2m, and 6m. The proof of concept is built and has been used in the field. I'll next build one without the snap T's (used to be able to adjust elements but none was needed) and a bit more attention to the fold up process to make it even better in the field.
Not sure if that will come before or after I try to a 2 element 20m from PVC and tent poles (with a non tent pole center portion of the elements)