A Free Antenna to Watch Free HDTV
Here's an easy-to-make High-Definition TV antenna that you can construct from cardboard!
Thanks to new high-definition TV broadcasting, there is no need to pay for cable TV or satellite TV to receive high quality local TV and major network broadcasts. Instead, in most cities, all you need is a good indoor aerial.
But what's the point of saving all that money if you have to buy an expensive (up to $70) digital TV antenna? Here's the answer - make one yourself!
I can hear your doubts - cardboard!? Aluminum foil?? Can this possibly work to pick up a good HD television signal?
Yes, it can be. The important part of any antenna is the actual design, not the materials. Aluminum foil looks as good as any other electrical conductor to the TV waveform.
These designs are the result of much calculating, experimenting and refining. The cardboard and foil materials makes them unique, even artistic. But no design compromises were made.
Our designs outperform most indoor antennas - even expensive ones.
This page is our Log-Periodic design. The advantage of this project is that it is very easy to construct. For an even more powerful version, you can also check out our Dual-Bowtie HDTV antenna lens here on Hubpages.
IMPORTANT: Here's the first thing to do. Click on the PDF link at the link below. It contains patterns you will need to print and cut from the paper.
- Click this link for the Log Periodic cardboard antenna patterns.
The colored link above should open the file in Adobe Acrobat or a similar PDF file reader.
Construction Hints and Modifications
Cardboard is the suggestion, but a material like Foamcor is also well suited. You could also use a substance like thin plastic or wood. Don't use thick wood or plastic, however, as these materials could actually begin to impede the TV signal. The lighter the material, the better. You can also dress up your cardboard with ink, markers, or colored paper.
For the aluminum foil, get the heavy-duty kind, it will be easier to work with.
Remember, the foil pattern is what does the work of receiving the TV broadcast - so pay attention to the measurements and the layout of the foil portions. Every other part of the aerial can be decorated or altered to meet your artistic expectations. Don't add anything else metallic, or reduce or change any of the foil patterns and spacings, and the antenna should still work.
For outdoor use, you obviously wouldn't want to use cardboard and foil. Instead, build the patterns from sturdy but porous materials like metallic window screen or expanded metal.
You'll notice that our material list contains a balun (see photos.) This is mainly included as an adapter that will make it easy to connect your TV receiver to the finished project. You'll see from our construction advice and from our links to buy baluns and wiring that there are different types of baluns and wiring. Use whichever approach suits you best.
Or, an alternative to a balun would be to cut the end connector off of a 75-ohm cable, strip the wires, and connect them directly to our antenna. Technically this could be an "impedance mismatch" but it's not likely to make a large difference in performance.
Wiring and baluns (also called TV matching transformers) are often available at dollar stores (where they will be cheapest) or at places like Radio Shack, hardware stores, building materials stores, or online at Amazon, eBay, and many other locations. We also will show you some links to purchase these materials further down the page.
How to Put it to Use
HD broadcasts are mainly in the UHF TV band, so our Log Periodic indoor aerial has been optimized for these channels.
You should find that this is a good general-purpose UHF-band antenna that is well suited for urban areas with strong TV signals. It is less directional than our other HDTV design, so it shouldn't need to be as accurately-aimed or carefully positioned. Simpler construction also means that you can use thinner cardboard, if you desire.
If you need maximum power, our other antenna, the Dual Bowtie design , is for you. This design can handily outperform other indoor models on the market selling for as much as $70. Construction is more complicated, but you still only need to cut out a half-dozen cardboard pieces.
Experiment with positioning your finished project before deciding on a final placement. If there are many walls between you and the TV signal, or aluminum siding on your house, it may be very difficult to hang on to a strong and consistent TV picture.
In these cases, see if there's a nearby window to aim your construction through. It could also be placed up on a higher floor, or in the attic of your house, and a long cable run down to your set.
Step-By-Step: Build your Log-Periodic HDTV Antenna
A very easy project. Just six steps. Here's all you need:
-Four squares of cardboard: Two 11x8 and two 8x8
-Aluminum foil, heavy duty
-Cable, either 75-ohm coaxial, or 300-ohm twin-lead
-A balun (see the construction hints section above)
Tools you will need
-Scissors and a sharp knife or box-cutter
-A ruler (or measuring tape)
-Paper glue, like Elmers or Gorilla
-A stapler - you could also use nuts & bolts (directions below will clarify.)
Locate the pattern for the Log-Periodic antenna you printed out earlier (see link at the top of this page.)
Using your scissors or penknife, carefully cut the pattern from the paper along the lines.
-Trace the pattern twice onto a piece of aluminum foil using a felt-tip pen. It is a good idea to tape it down while you do this, but attach just a tiny corner of tape to the foil, otherwise you'll have trouble loosening it.
-Carefully cut out your patterns (you'll need two, exactly alike) from the foil.
-Measure to find the exact center across the long edge of one of your 11x8 pieces of cardboard, and repeat at the other long edge.
-Draw a line there connecting those points where the 'trunk' of the foil 'tree' will go. Glue the patterns to the two 8x11 squares of cardboard. Try running a line of glue up the center line you just drew, and lay the foil there. Then run glue under each 'branch', and press down. Position carefully (with the 'trunk' of the 'tree' centered on your line), and press on the foil to smooth. Both squares should look the same, with the foil placed exactly the same way.
-Connect your cable and balun wiring to the small ends of the foil patterns.
-If connecting 300-ohm flat twin-lead, separate the wires and strip about 3/4" of the insulation off, then staple the exposed part of the wires to the shorter end of the patterns, one wire to each of the cardboard squares. Your square-type push-on balun is then screwed to the opposite end of this wire.
-If connecting a tubular 75-ohm balun directly to the antenna, either staple its wires or alternatively, drill or punch a small hole and install a small screw, washers and bolt to the small tab at the short end of each foil pattern. This will be used to attach the wires after assembly. (The drawback of screws is that they can never be tightened down very hard onto cardboard.)
-Arrange the two squares of cardboard with foil patterns into a wedge shape, and glue the 8x8 cardboard squares onto the sides to hold the wedge in shape. Look at the picture to clarify. The two faces are NOT mirror images after the cardboard sheets are mounted - the two longest branches of the two foil "trees" should be pointing in opposite directions.
-The short ends of the patterns (the wired ends) are at the narrow end of the wedge. The wedge should form about a 45 to 55 degree angle (the exact angle is not critical.) The foil patterns can face inward (at each other) or outward (away from each other.) Don't mix! At the narrow end of the wedge, the two pieces of cardboard should wind up about 1/2 inch apart. If your foil patterns are arranged facing outward, the sheets can be even closer at the narrow end. It may be useful to tape the pieces together first, and then apply glue when you've got it right.
-If you haven't connected your balun or wiring yet, do so now. It's done!
Connect your cardboard Log-Periodic antenna to your TV set and try it out. Experiment with the placement, rotation and height until you find a good orientation it can live in. Generally, the small end of the wedge should be pointed toward the TV station you want to receive.
Congratulations! You have just built one of the easiest and most effective indoor HDTV aerials available anywhere!
Want to make another, even more powerful version? Look at our Dual Bowtie HDTV antenna lens, also here on Squidoo.
Parts you may need
You'll need a couple of inexpensive parts for this project, which you can shop for where you live, or buy here from Amazon.
You need to find a "balun" and a cable which connects to your new cardboard aerial.
There's a square push-on type balun, which is used with the flat 300-ohm type antenna wiring. Or there's a tubular-shaped type balun, which is used with round 75-ohm cable.
So, you can do it the "flat" wire or "round" wire way. Either method should work fine.
If making long runs of cable, or splitting the signal to multiple TV sets, you could also add a TV signal amplifier.