DIY HDTV TV Antenna (Bowtie)

Build your own HDTV TV Antenna to cut the cord from your cable provider and save $1000 a year. This DIY antenna is very easy to build with just a few basic tools and a few supplies available from the hardware store.

After being disappointed with the current channel offerings and ever increasing price of our local cable provider, we recently decided to disconnect our cable TV service and go for over the air broadcasts as well as the many online services available now. I built this DB4 antenna, also called a bowtie antenna, to increase the rang of signals I could pick up over the basic rabbit ears antenna.

This is the first of two antenna designs I’ve built. Subscribe or come back soon to see the second version of the DIY HDTV TV antenna.

Parts Needed:

13 feet of 12 gauge Electrical wire

10x Wood Screws (I actually used 6 x 1/2” metal screws)

10x #10 Washers

Matching transformer (balun)

1×3 or similar size board around 22 inches long

Start by cutting the 1×3 to length and marking the spots for the holes. Make the first set about 2 inches from the top and then measure 5 1/4 inches to the next set and and continue down making each set of holes 5 1/4 inches apart. The holes for each set will be centered on the board and 1 inch apart.

Drill out the spots you marked for the screws with a 1/16 drill bit. This may be unnecessary, but I like to do it to keep the wood from splitting.

Cut 8 pieces of wire about 15 inches long. They only need to be 7 inches after folding in half, but I like to add a little extra and cut them to length later. I bought electrical wire off the spool by the foot. You can also get romex type 12-2 or 12-3 house wire with three or four wires in a sheath (hot, neutral, ground). Romex is a couple cents cheaper per foot, but requires more work to split the sheath and separate the wires.

I couldn’t find any bare wire, so I needed to strip the insulation off the areas where the connections needed to be made. I used a wire stripper to score both ends of the area to be stripped then used a utility knife to split the insulation and peel it off.

Bend the wires into “V” shapes then cut two more pieces of wire about 17 inches long to connect the bowties. Strip the ends and three spots on those wires to make contact with the center nodes and the center tap. (only the two nodes are shown stripped in the picture below)

Next put everything together with the screws and washers. Make sure everything is snug and all the bare areas of wire are touching. Measure from the screw to the tips of each “V” and cut them off at 7 inches. Then spread the tips apart 3 inches.

This is the only kind of balun (matching transformer) I could find at the hardware store when I was getting the other supplies. It isn’t exactly what I was looking for, but it will work with a little modification. This matches the high impedance of the antenna to the lower impedance of the receiver.

This is what it looks like on the inside.

I cut a hole in the side of the balun then cut the end off a piece of coax cable I had and soldered it to the contacts of the coax connection.

So it looks like this.

I cut, stripped, and bent two short pieces of wire to attach the balun to the back of the antenna.

I screwed the connections for the balun to the front and wrapped the wires around to the back so I could attach it to the back.

Here I screwed the cover for the balun to the back of the antenna to hold it in place, then attached it and secured the wires with the pigtail hanging down.

And here’s the end product. I used some scrap wood to build a base for it. What you do here would depend on where you plan on mounting it. I just wanted to set it on a shelf for testing, so a simple base worked for me. I will eventually mount it permanently in the attic for better reception.

Results:

Here are the results I achieved after switching from a normal set of rabbit ears to the bowtie antenna.

I’m using an HDHomeRun connected to my windows media center as the TV tuner. Below is the software that came with it showing the signal strength.

As you can see, the signal strength went down, but the signal quality went up, which I think is the more important number.

Update:

While, the reception was better, it wasn’t what I was expecting, especially since I live just a few miles away from several TV stations. I finally found a different kind of balun (matching transformer) at Radio Shack and decided to give it a try.

Results Round #2:

As you can see here, switching to the better balun made a significant improvement. The signal strength is still lower than the original rabbit ears antenna, but the signal quality is noticeably higher.

Update #2:

I’m still not happy with the results, and after doing some research, I think the issue is signal reflection. Basically, since I’m so close to the source and the signal is so strong, I’m getting reflections of the same signal from different directions at slightly different times. These out of sync signals are interfering with each other and causing the signal to drop out often.

To solve this all I need to do is to add a reflector to block the signals coming from behind the antenna. I didn’t discover this until after I had built a different design. To see my new design based on the Gray-Hoverman Antenna and the reflector I added to it, stay tuned to this blog by subscribing to the RSS feed or the email newsletter at the top of this page and you will be informed as soon as I have posted it.

Let me know if you have tried this design and what your results were in the comments below.

Azega