DIY UHF antenna

June 27th, 2009

 I’ve just bought a TV few days ago and don’t want to pay cable/satellite companies hefty monthly subscription.  So the first step is to start with some easy sources, like local TV stations.  I had an antenna from BestBuy before, and the reception was completely unacceptable.  Doing a little Googling showed me that poor peons like me shall cook own antenna.

The US is already transferred to digital TV in June, so I need only build a UHF antenna.  There are many different types of antenna on the web, for example, the bow-tie on YouTube, or the Gray Hoverman (a.k.a super antenna).  I’ve also found another design from forums in Taiwan (four diamonds, demonstrated in the following).  Since the UHF frequency of Taiwan (600MHz) is the same in the US, I decided to give this four diamonds a try because it’s easier to DIY than bow-ties and Gray Hoverman.

Materials needed:

RCA Matching transformer: the link goes to Amazon, but I bought it at Home Depot like 4 bucks after tax

7 feet of 12 Gauge copper wire (Home Depot sold it 26 cents per feet)

The structure of this antenna is shown here

Use the copper wire to build four equal size squares of 12.6cm long in edge (4.96 inches, it’s much easier to steal my kid’s ruler which had both inches and cm on it).  I drew the shape on a cardboard first, and then started the wire routing.  The wire I use is insulated.  If your’s is not, make sure you insulate the cross-over of the diamonds except where you connect to the transformer.  Once the diamonds were laid flat on the card board, we could connect the transformer onto it.  I use electrical tapes because it’s, you know, easy.

Here’s the finished picture, crystal clear HD image from NBC.  My place is in Torrance and I’ve got 30+ stations with this DIY antenna.  REALLY HAPPY.

I’m not an antenna engineer, thus unfortunately I don’t know exactly why this thing works and how good it is.  Here are the things I know of from its designer:

1. This antenna is directional, you need to find the best spot in your place to get good signal
2. The four diamonds MUST be posed vertical (up to down).  Horizontal (left to right) won’t work.
3. You can add reflection board (sheet of aluminum, 8cm apart parallel to the antenna) to enhance its signal.  I didn’t do so because I’ve already got strong enough signal.

This thing can definitely be beautified and that will be my next project.  Meanwhile I’m going to enjoy some TV first.

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