Operating notes: vacation, building a copper-pipe J-pole

Last weekend, I went “up north,” as we say here in Michigan. What that means is that we drive up to northern lower Michigan and spend a couple of days on a lake. Normally, I’d take my KX-1, throw an antenna  up in the trees, and operate QRP.

This year, however, I opted not to take my stuff. Instead, I chose to work on my upcoming book, The No-Nonsense Guide to Amateur Radio. I made some good progress on the book, which will be a combination of Ham Radio for Dummies, AC6V’s DXing 101, and the ARRL Operating Manual, with my twist on things.

A Petoskey stone, the state stone of Michigan, is a fossil colonial coral. These  corals lived in warm shallow seas that covered Michigan  during Devonian time, some 350 million years ago.

A Petoskey stone, the state stone of Michigan, is a fossil colonial coral. These corals lived in warm shallow seas that covered Michigan during Devonian time, some 350 million years ago.

When I wasn’t working on the book, I was in no particular order:

  • looking for Petoskey stones, the state stone of Michigan, on the beaches of Grand Traverse Bay,
  • organizing the more than 300 books I had on my Kindle,
  • playing different board games and card games with my sisters and their kids,
  • cooking and eating and eating and eating.

I had a blast, except on Saturday. Saturday was cold and blustery, and the high winds at night forced the people running the Elk Rapids Harbor Days festival to cancel the fireworks show. I was also looking forward to a BBQ chicken dinner by the Elk Rapids Rotary Club, but by the time I got there at 5:30 pm, they’d run out of chicken. I had to settle for a Lions Club bratwurst instead.

Building a copper-pipe J-pole
A couple weeks ago, I was talking to one of my recent students, Prem, KD8SRV, and we got to talking about how to increase the range of his HT. I don’t remember exactly the entire course of the discussion, but he decided to build a copper-pipe J-pole. He purchased all of the materials for the antenna and came over to my house yesterday to build it.

We used the instructions on the website of the Colorado Douglas and Elbert County ARES group.

Cutting the pipe proved to be the first challenge. Prem had previously tried to cut the pipe with a Dremel tool, but as you can imagine, the cut was uneven and not all that easy to make. I have a pipe cutter, which made a better cut, but it wasn’t a very expensive tool, and it proved to not be very sharp, but with a little elbow grease, Prem was able to make all the necessary cuts.

Next, was soldering the pipes together. Prem had purchase a propane torch, flux, and solder. This was his first attempt at soldering copper pipe, and let’s just say that the first solder joint was perhaps a little marginal. He improved as he went along though.

Finally, we had to decided how to attach the coax to the pipes. The plans showed drilling a hole in the stub and mounting a BNC connector there. I didn’t like that arrangement, so I attached some wires to an SO-239, and we soldered those to the pipes with my 100W soldering iron.

That worked OK, but we still need to find a better solution. One that holds the SO-239 more securely. I just Googled a bit and found a better mounting scheme on the “Zombie Squad” website of all places. If you’re reading this, Prem, take a look at how they did it.

After connecting the wires, we propped up the antenna in my basement and connected the antenna to my 2m rig. The SWR was just under 2.0:1 on 144.63 MHZ and about 1.5:1 on 146.36 MHz. That’s not too bad, and should be better once the antenna is outside and in the clear.

This was an interesting project. I’ve made many 450-ohm ladder line J-poles, but this was my first copper-pipe antenna. It takes practice to solder the pipes correctly, especially with  lead-free solder.

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Comments

  1. Here is how I mount the feed point for my J pole: http://imgur.com/a/gTYwo Looks to be about the same as the forum you link to. Solder the ground straight to the 3/4 wavelength section and then a piece of 16awg as a jumper to the other side.

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