I’ve constructed a 144/440 Dual band Open Stub J-Pole Antenna.
I saw the plans for this on the internet (link to plans) by Allen Lowe (N0IMW). Since I had a Metal Fabrication backround I thought this would be an easy build.
I also created a PDF and JPEG Version which you can download if you like.
I did some minor changes from the above. Instead of using nuts I used pressed “PEM” nut on the underside and used thread protecting vinyl caps on the tips
Here are some SWR Shots. I don’t have state of the art equipment so this will do for now
It was a really fun and quick build. Plus it works okay. It’s no Diamond X510. What else do you expect for around $20 in parts? I love it.
If for whatever reason you can not build this. It is manufactured by the designer of this antenna and has them for sale on his website for a reasonable price. So check out ARROWANTENNAS.COM for the OSJ and other quality crafted antennas.
EDIT (5/2/11): I’ve Also built a “Adjustable” version of the Open Stub ( OSJ ) J-Pole as seen HERE.
EDIT (10/20/2011): Someone let me use a MFJ Antenna analyzer so here is a reading from the VHF side of the Antenna.
@ 145.98Mhz I got a reading of 1.0SWR with a 51ohm impedance. The antenna was resting on a wooden chair so I am not sure what the value would be when fully installed but I don’t think it would change that much since it doesn’t need grounding.
Here is another reading on the VHF side of the antenna