As I mentioned a while back, last year I built a 2m 1/4 wave ground plane antenna to use with my handheld transceiver. I wanted a better antenna than the rubber ducky that came with my radio, and I also wanted to build an antenna. I think I posted about it on the old version of my blog, but the post didn’t get brought over.
I used plans from here. The center part is a SO-239 connector I bought at Radio Shack, and the radiating element and radials are made out of uncoated brazing rods that I procured at a farm supply store. The vertical (radiating) element is 19.3 inches long, or a quarter wavelength electrically for the 2m band (144-148 MHz). The radials are slightly longer.
It works quite well. When I tune my radio to the local National Weather Service station I get a few S units of improvement over the rubber ducky antenna. Each S-unit is 6dB, so that’s quite an improvement. Using this antenna I can get into the local repeater when I didn’t have a prayer with the rubber ducky. Of course, now I use my Diamond antenna mounted on the house.
I intended to borrow an antenna analyzer from a local ham to see how close to 50 ohms I had managed to get. I never did, but I’ll be sure to do it when I borrow the analyzer for another project. Given the way it performs, it has to be relatively close.
A few more pictures here.
Just wasting some in between class time on Digg and I found your article . Not typically what I like to learn about, but it was absolutely worth my time. Thanks.
Hello,
I’m interested to building this little 2 m 1/4 ground plane antenna. I have just a couple of questions.
Can I use plastic coated coat hanger wire or should I strip it back?
Also the vertical element. It seems that It would be rather tricky to solder it to the top of the So239 as there’s not alot to attach onto. What should I use for the vertical? , brass, copper? Would an ordinary soldering iron do the job?
regards,
David VK2FEAA
it works quite well with alinco dr-135.
David,
I apologize for not replying sooner.
If you used a plastic-coated coat hanger you’d need to strip back enough of the plastic to get a good connection between the SO-239 connector and the coat hanger.
Don’t worry about the particular metal too much. Just as long as you can get a good solder joint.
You’ll need a relatively beefy soldering iron due to the thermal mass of the vertical. This is one case where a soldering gun might come in handy. Be careful not to melt the dielectric in the SO-239 connector. I managed to do that once before getting it right.
Let me know if you have any more questions.