The point where the tuning stub attaches to the main element is the j-pole antenna’s ground point. That is why you can make it any length. Its a good idea to provide a ground here. This too will help with lightning protection. (provided your tower is properly grounded!)
Only use rosin-core solder. Don’t use “plumbing solder”, acid-core solder, or plumbing paste. The acid in these materials breaks down the solder joint when electric current passes through it.
The photo to the right is one of my j-pole antennas that I use. This one is not the 2 meter version described here, but rather the 70 cm version of the J-Pole antenna.
So there you have it. I have built several j-pole antennas, and they work great! This one has been up for about 7 years. You can see how the pipe turns black from the weather. This is normal, and doesn’t hurt the performance of the antenna in any way.
This article was originally posted on www.mikestechblog.com Any reproduction on any other site is prohibited and a violation of copyright laws.
Jay Leatham says
Mike does the feedline for the pvc pipe antenna inside the pipe or outside?
WB8ERJ says
Hello,
It really doesn’t matter if the feedline is inside the pipe or outside. Since its easier to put it on the outside, that is how I build my J-pole antennas.
Jay Leatham says
Mike, I want to make a old tv antenna into a 2 meter yagi . can it be done.
WB8ERJ says
Yes it can be done. I have done it a couple of times. However there is one caveat, which is mainly a mechanical issue. Since most TV antennas are what is known as a Log-Periodic Dipole Array (LPDA) that the elements are in a Vee configuration, that would make re-building the TV antenna into a 2 meter Yagi more difficult. Sometimes you can find a LDPA whose elements are perpendicular to the antennas main boom section, those are the ones that can be rebuilt. With those its a simple matter of drilling out the rivets and placing the elements at the proper spacing. Then cut them to the proper length for 2 meters.
Old TV antennas are a good source of aluminum for making various ham radio antennas.
Good luck!
— Mike