Tech Minds: Building a Low Cost VHF/UHF Antenna from Copper Tape
In his latest YouTube video Matt from Tech Minds shows how to build extremely low cost antennas out of copper tape. Rolls of copper tape are commonly found very cheaply in garden stores as slug barrier tape as garden slugs will not travel over copper.
After using a dipole calculator Matt solders coax to two strips of copper tape, resulting in a rudimentary dipole (without balun or choke). His first test with a UHF sized dipole showed poor SWR and yielded poor results on an actual radio/SDR. But his second test with a VHF sized dipole actually yielded decent results.
Step to make an antenna using copper wire. Step 1: Estimate how old your antenna will be. Step 2: Cut the coaxial cable at one end. Step 3 – Strip half the length of the antenna from the end of the coax cable.Step 4 – Cut the copper tubing to half the total length of the antenna. Step 5 – Connect the coaxial cable to the copper pipe. Step 6: Solder the protective layer of the coaxial cable to the tube. Step 7 – Connect the coaxial cable to your audio receiver.Step 8 – Set up the copper antenna.
As a DIY enthusiast, you surely want to make many things inexpensively with the technical items that exist in your home. As you may not know, making a radio antenna is one of those fun and inexpensive DIY projects.
I did something like this back in the late 90’s when I had a job high up in an office tower. I was next to an exterior window with a good view of the local city. I didn’t use a dipole, but a J-pole because it’s much easier to match to a 50 ohm line–you can move the match point up and down the copper tape until you get a low SWR.
The challenge I had was that the antenna was lossy and didn’t match up with the calculations–even when I included the dielectric value of the glass. Turns out it was likely due to the metal deposited on the glass to tint it. That acted as a resistive layer and ate a little of the power. It was still quite a few db better than the little rubber-duckey antenna on the HT I was using.
I used little copper grounding clamps from the hardware store to connect the co-ax to the copper foil until I found a good match and then I very carefully soldered them together and covered the junction with a big chunk of clear tape to hold everything in place and act as a strain relief. It worked great for the few years I worked there.
I’ve found that using a network analyzer tends to help for these kinds of things. I was making an antenna out of speaker wire, and the velocity factor was way off from the calculations I’d been using.
I didn’t have one, and it would have looked really odd to drag one into a business setting and stand by the window fiddling with it. I was flying under the radar as it was, so to speak.
Definitely thinking out of the box, what a great idea, thanks.
Agreed. This is a neat idea. I imagine you could create a helical directional antenna with circular polarization pretty easily with this tape, wrapped around a properly cut and formed cardboard tube. Or if the diameters are convenient, maybe even some PVC pipe.