Hardy Menagh   6/9/16

After making a HDTV Antenna, using directions from the Web, I decided I could make a better-constructed version that could be left outside without rusting and failing, if needed.

We live in a fringe area where, in the analog days, there was no over-the-air TV reception, even with a good antenna. When I learned of a low-power digital TV transmitter on a nearby mountain peak, I decided to construct an antenna to see if I could get the signal.

A Web search, provided several different designs for do-it-yourself antennas. I selected one that listed dimensions that were closest to the commercially available HDTV antennas, which cost upwards of US$100.

This design used coat hanger construction with screws and washers forming the mechanical connections. I didn't have wire hangers (Joan Crawford would be proud) but I did have 1/16" music wire, so I used that.

The antenna worked, sort of, but I was getting pixelation and drop-outs. The commercial rooftop units utilize two of these types of antennas in parallel so I decided to construct two more identical units, using copper wire and reliable solder joints.

This is not meant to be a step-by-step instruction manual. Look at the other instructions on the Web to get an idea of the layout of these antennas. If you have the skills necessary to drill accurate holes, glue dowels and make good solder joints, you won't need instructions. Just take a look at what I did and do the same but if a better way occurs to you, do it!

I can tell you that this design produced better results than the screw-together one with the same dimensions. When paired with another identical one, the signal is strong and glitch free. Too bad there's nothing on...

Tools:

• Typically, you'll need a saw which can be either hand or power, a hammer, a drill, fine nosed pliers, wire cutter, soldering iron, screwdriver, fine sandpaper to clean the joints before soldering, a marking knife or awl and tinsnips to cut aluminum flashing.

Materials:

This is what I used. Most of it was dictated by what I could scrounge. The only purchased item was the Matching Transformer.

• A 31" length of clear Fir 2" x 4". Pine will work too but if there are knots, make sure they don't coincide with the areas where the staples need to go. If the wood is fairly hard, it may be necessary to pre-drill the staple holes with a slightly smaller drill size.
• 8 short 1/8" dia dowels. Might not be absolutely necessary but serves well as a third hand for precise alignment.
• Waterproof glue. I used Titebond II. Only necessary if using dowels.
• For the wire, I stripped the insulation from some used 12 AWG solid copper electrical wire. I also used this to form the staples. Copper wire is easy to bend which can be both an advantage and disadvantage.
• Electrical solder.
• Aluminum flashing for the reflector. You might be able to scrounge some scrap at a construction site or local dump/recycle station. You might also be able to use wire lath, an old aluminum window screen or even hardware cloth.
• A 75 - 300 Ohm Matching Transformer.
• Two plated wood screws to attach the transformer.
• Coaxial cable with connectors installed. Length to be determined by your specific needs.
• If you make two antennas, you'll also need a signal splitter and two shorter lengths of coaxial cable to connect them.
• Galvanized roofing nails to attach the reflector to the board.

Construction:

I used the measurements from the first antenna I built with directions from the Web.

The elements are 8" long, made by bending 16" sections of wire. They are spaced 1 - 1/4" apart horizontally and the pairs are spaced 8" vertically from the attachment points. The open ends of each "V" are 5" across.

I used a marking knife to scribe all measured lines on the board. This avoided any electrically conductive "graphite traces" that might come from pencilled lines or metallic components in pen ink.

I used short sections of dowel glued into the board to align the elements and attached the elements to the board with copper staples. All of the joints are soldered. Two copper washers are soldered to the connecting wires to allow the matching transformer to be attached with screws. You can also solder the transformer leads directly to the connecting wires. Make sure to insulate the connecting wires in both places where they cross.

If you are mounting two antennas in a frame of some kind and they'll both be aimed in the same direction, you'll only need one Matching Transformer. Just wire the two together as shown and attach the transformer in the center of the connecting wires. This allows a single run of cable and eliminates the splitter. The mount for the transformer in this case is a piece of softish plastic cut from an old office chair arm. It holds the screws securely and is non-conductive. The insulation is left on the connecting wires everywhere but at the solder joints.

For exterior use, you'll want to paint the wood board with non-conductive paint or exterior varnish before assembly. If mounting out in the open or on a roof, the flashing reflector will be problematic, as it will catch wind which may have destructive consequences. The commercial units use a series of horizontal aluminum tubes for a reflector. This allows the wind to pass through the antenna with minimal resistance.

The last thing to do is find the right location for your antenna. A foot or two of distance or a couple of degrees turn can make a big difference. Mine seem to work just as well in the house as outside. Your experience may differ.

Enjoy your free programming!

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