Sunday, November 27, 2011

Deoxyribonucleic…Fractal Antenna?

As you may guess, from the photos below, this post is brought to you by the letter ‘B’, and not your regular sponsor, ‘M’ [Bryan, not Melissa]. I have been hard at work over the last few weeks designing and building a new television antenna and, as any good engineer will agree, a normal antenna just won’t cut it – too boring. Here’s how my latest creation evolved…

Earlier this year I happened to be watching NOVA on PBS and saw an episode titled Hunting the Hidden Dimension (if you like NOVA and haven’t see this episode you’ve really missed out) which was all about fractals. The show got to talking about the wonders of fractal antennas and how they have changed the wireless world – nearly all modern cell phones use fractal antennas (that’s why you don’t have to pull the antenna up anymore to receive a call [As Peter does in the opening scenes of the movie Hook]).

Naturally, during lunch the next day, I decided to do a little searching online about fractals. As it turns out, geeks all over have built their own TV antennas using fractal patterns. I decided to do the same. I followed the same basic fractal pattern most of them used, but designed the rest myself. The result?

I present, exhibit A:


I expect my Mom will want to frame a picture of this and mount it on her mantel as Bryan’s first fractal antenna. This antenna performs reasonably well, better than the rabbit ears it replaced, but still doesn’t quite live up to what I had envisioned – we still periodically lose the signal as we did with the old antenna, though less frequently. As a result this antenna was relegated to the small TV. Back to the drawing board.

Then, a few months ago I remembered something one of my best friends, Matt Pierce (the greatest home teaching companion I’ll likely ever have), told me during one of our home teaching trips. He had talked about – now, try to picture this from the perspective of a teenage boy – the homemade TV antennas (didn’t know people did this) he made from cardboard and aluminum foil. In my mind’s eye I saw a monstrosity of crinkled foil and left over pizza boxes taped to the back of a TV. And who knows, perhaps Dominoes is still delivering great reception at the Pierce home to this day.

So, after my first disappointing attempt I launched a new, more ambitious, effort to prevent the untimely loss-of-signal at critical moments in the latest episode of Terra Nova (I like this show, though Melissa’s not much of a fan). Inspired by my home teaching companion of years ago, I decided to forgo bent copper wire and use aluminum foil. I don’t know how Matt made his antennas, but I concocted a plan which involved visio-designed fractal patterns, I went with five different fractals instead of just one, etched into foil which I mounted on a plastic substrate and covered in a protective layer of contact paper. My first antenna constrained the elements to just 2-dimensions, a mistake I wasn’t going to repeat (though probably not the real, or only, reason my signal strength was disappointing). The result is pictured below:


The world’s first, perhaps last, double-helix multi-fractal TV antenna! If you can’t see the double helix structure, just look closer : )  You’re probably wondering about the performance? We now get 6 more channels than before! (Although, we’re going to delete all but 3 as they are just analog duplicates of digital stations we already get.)


I decided to go all out on this antenna and purchased all the proper hardware. To help keep the antenna attractive looking (though the antenna sits where it’ll seldom be seen) I threaded the wires up through the superstructure and then out the base; the electrical connection is made via zinc screws, nuts and washers. Pictured below: each of the five fractals I used in the antenna design and an alternate view of the completed antenna.  Enjoy!