Project Page: Fractal HDTV Antenna

Trouble Tuning In

Finding my myself in need of an antenna to bring in HDTV signals, I turned to the internet and found plans for a fractal antenna and decided to try my hand at making one.  I did not know if it would work but it seemed easy enough to whip up a prototype.

The type of antenna that I made consist of four fractals arranged on a base with a 75 Ohm matching  transformer hooked up to wires that connect each pair.  The base of my prototype is a piece of plywood purchased at a craft store.

Fractals should be made from thicker wire but 22 AWG hookup wire is what I had and that’s what I used.  Six sheet metal screws held everything together.  The good news was it worked pretty well.  The bad news was it worked well enough that I put off making the next version for too long.

Although it worked, the prototype suffered from not being mounted to anything.  If we had to reposition it to pull in a channel it needed to be put down just so.  This led to many crashes to the floor, causing the fractals to get misshapen and swiveled out of position.

For the next version I decided to stick with plywood for the base.  This time I used my Dremel  to cut enough for base from a larger piece that I had on hand.  Since I wanted really sturdy fractals I cut up some wire hangers from our closet.  Cutting coat hanger wire with a Dremel cutting wheel make an amazing show of sparks.  I made a jig from scrap wood and carpet tacks to help bend the wire.

Bare plywood was fine for the prototype, I decided to coat the new one with polyurethane to spiff it up a bit.  Fancy brass fittings replaced the plain old machine screws.  The big question still was how to mount the antenna.  Our TV is next to a bookcase, the Antenna would have to mount on the bookcase.

Inspiration struck when I spied “self portrait” sticks at the dollar store.  These sticks are suitable for several reasons.  They are telescoping for good height and allow the antenna to pan and tilt.  The end of a selfie stick is meant to hold a phone.  Attaching a phone case, also purchased at the dollar store, to the antenna base with some plastic spacers meant a perfect fit.

The 75 Ohm matching transformer hangs on the back of the antenna with the connectors passed through a hole to connect to the fractals.  The mount on the selfie stick holds it in place.  The stick is attached to the bookcase with Bongo Ties.

I am very satisfied with the result.  The new version is really easy to pivot if necessary and the added height seems to help pull in signals.  I think that thinner wire might have been better to use because it is difficult getting the correct angle bends with coat hanger wire, even with a jig.  It would be easy to swap in new, more precise, fractals if I ever see a reason to.