This antenna design grew out of my attempts to build an indoor HDTV antenna using fractal patterns after I had watched a TV show and had read a magazine article on the use of fractal patterns in cell phone antennas, My goal was to design an antenna that not only worked well, but one that was easy to build and could be built from easiliy obtainable materials.
The result is an antenna that is somewhat omnidirectional, and performs well receiving digital TV signals at my home from the low end of the VHF high-band (i.e Channel 7 at 174 MHZ) to the high end of the 600 MHz UHF band. (There are no channels in the 700 MHz band in my area, but Channel 51 at 692 MHz is one of the strongest signals here.)
This antenna can be used at a maximum line-of-site distance from the broadcast tower of about 50 miles for high power stations, and somewhat less for low power stations. I'm sorry that I can't be more definite about these distances, but a lot depends upon the type of construction used in the building and the location of the antenna within the building (e.g. downstairs living room vs. second story bedroom or attic).
So, with all that in mind, let's get started.
Step 1: Gather Needed Materials
The materials you will need are:
- A 150mm X 400 mm ( 6 inch X 15 3/4 inch) piece of poster board. This is the stuff from which cake boxes and the gift boxes for shirts and blouses are made. A 24 inch X 28 inch sheet of it can be bought at hobby stores and other places for less than a dollar.
- The pattern for the antenna. Download the PDF file at the bottom of this page.
- Some cellophane tape.
- Map pin or other sharp pointy object for punching holes in poster board.
- 3.2 meters (~10.5 feet) of small diameter (24 - 20 AWG) copper or aluminum wire. This can be salavaged from an old discarded electric motor or purchased from a hobby or hardware store.
- Crimp connectors and crimping tool or a soldering iron and solder for connecting lead-in wire to antenna.
- A length (let your situation be your guide as to the length) of 300 Ohm twin lead antenna lead-in wire and a 300 Ohm to 75 Ohm matching transformer. The matching transformer can be purchased from Radio Shack, Wal-Mart, Target, on-line, or at any number of hardware stores. Best prices are found on-line, you just have to wait a few days for delivery.
- A length of 75 Ohm coax and a in-line 300 Ohm to 75 Ohm matching transformer can be used instead of the 300 Ohm twin lead antenna wire listed above as Item 8. It's getting harder to find the good old fashion 300 Ohm twin lead antenna wire, and all the TVs manufactured in recent times have antenna connections for 75 Ohm coaxial cable.
- A craft knife or other knife with a small sharp blade for cutting Slots A & B in antenna form.