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Free your TV—make a digital antenna for under $10

February 12, 2017

diy-ota-digital-antenna

On Friday (February 10), a septuagenarian do-it-yourselfer and I were talking about the over-the-air digital TV signals available in the Vancouver area; something relatively few Vancouverites seem to be aware of. At one point I was given an offhanded description of the dandy DIY antenna that this fellow uses to pull in something like six TV stations for free.

My elder friend is the sort who built himself crystal radio sets as a child and he grew up to be a very capable tinkerer. For many years he refurbished discarded computers just to give them to the less fortunate (that is, people lacking his repair skills).

I very much respect his do-it-yourself mindset and I pumped him for enough information so that I could provide both the clear diagram which heads this post together with the additional details needed to build his homemade HD TV antenna—all of which follows below.

Something the cable companies don’t want you to know?

Many people are unaware that the air over North America is still full of free TV signals. There are, in fact, 18 over-the-air (OTA) digital TV channels in the Vancouver, B.C. area alone, including CBC English and French, CTV, CHEK and Global.

Back on August 31, 2011, when the Canadian government’s Radio and Television Commission (CRTC) decree an end to analogue TV transmissions, all this meant actually was that OTA TV transmissions switched from analogue to digital.

I have never had the occasion to see digital OTA TV reception but I understand that it comes in crystal clear and generally yields a wonderful high definition picture—if, that is, one has a digital-capable TV needed to pick up the signals.

If your television set has a built-in digital tuner (which it almost certainly does, unless it was made much before 2006) you can see what channels you can pick up out of thin air by simply toggling your on-screen reception settings from “Cable” to “Antenna”—or perhaps to “Air” (consult your manual for specifics). For best results though, you may need to hook up an actual antenna to the “Antenna” port on the back of your digital-capable TV set.

You can buy an antenna for anywhere from $50 to several hundred dollars.

There is a lot of information on the Internet about buying and configuring an antenna to receive OTA HD TV. Much of the information, like DisableMyCable, or this page about choosing an antenna for Vancouver, is provided by companies which sell the antennas for digital-capable TVs as well as digital converter boxes needed to make older TV sets digital-capable (so you can buy antennas for them).

The Internet can also show you many ways to make your own cheap and cheerful antennas—such as this folded dipole antenna, this mesh and steel wire number, or this cardboard-tinfoil wonder.

The specific virtues of my friend’s OTA HD TV antenna are its simplicity and the fact that it requires no soldering and needn’t cost anyone more that $10. Otherwise it is quite similar to any number of other DIY antenna designs found online. In particular, I found a “Vancouver special” shoebox and mesh arrangement which, as one particular image shows, boils down to the exact same design that I’m detailing in this post.

Making the antenna

To make the antenna shown in the diagram heading this post you will need the following items:

  • A digital-capable TV set with an antenna port that accepts a standard coaxial F connector (check before preceding).
  • A steel wire coat hanger.
  • A boxcutter knife and whatever works to remove any coating from the hanger.
  • Something to help you measure, mark, bend and cut the coat hanger.
  • Sufficient coaxial cable to reach from your digital-capable TV to a window or balcony.
  • A two-position, screw-type terminal block for wiring two connections without soldering.
  • A slot-head screwdriver.

Terminal blocks are an inexpensive hobbyist tool to allow electrical wires to be joined without soldering. These blocks come in various lengths of side-by-side holes (or terminals), through which pairs of wires can easily and securely be joined by screw turns—and just as easily un-joined.

Plastic-bodied terminal block strips are sold at various lengths and can be cut up (like unsliced loaves of bread) to provide the necessary “slices” of terminal connections for a particular project. My friend’s antenna only needs two wiring connections so, for purposes of illustration, I have chosen a two-position ceramic terminal block costing $1.20 at Lee’s Electronics, which is located in Vancouver, at 4131 Fraser Street.

The terminal block is not essential—there are other ways to fashion the necessary connections, such as soldering. But the terminal block takes care of everything in one stroke, including the necessity of rigidly fixing the relative positions of the two antenna pieces.

Apparently, any steel wire coat hanger will do but it is imperative that the steel wire be made completely free of any outer plastic or enamel coating.

The bare steel wire coat hanger needs to be cut up and bent to yield two neat L-shaped pieces, with the long sides of each measuring exactly 6 inches (15.24 centimetres). The short sides can be whatever.

As for the necessity of the six inches, here’s half of an explanation: the length of the conductive elements (the long sides of our steel coat hanger pieces) needs to be about one half of the signal wavelength to be captured.

Insert the short sides of the coat hanger pieces into the holes on one side of the terminal block (as shown in the diagram) and tighten down the locking screws, making sure to keep both pieces of wire perfectly parallel to a flat surface.

Choose a coaxial cable with a standard F connector (if you’re in North America) on one end and which is maybe a metre in length longer than is comfortably needed to reach from the antenna port on your TV to one or more of your windows and/or to your balcony.

The price of coaxial cable increases according to the amount and conductivity of the metals it contains. In addition to plain old copper coaxial, I have seen some that has a shield weave of silver-coated copper, which is more conductive than copper alone and some with a weave of aluminum, which is about 40 percent less conductive than copper.

I would assume that more conductivity is better for an antenna but I read that the bog standard coaxial cable sold with most commercial antennas (RG-58) has an aluminum shield weave. RG-6, seems to be the most common coaxial cable sold in Vancouver retail stores and is supposed to be quite good for antennas.

Use a boxcutter to strip one end of the coaxial cable—leaving an end with an F connecter to screw on to your TV’s antenna port. Strip the end, as per the above diagram, to reveal enough length of both the shield weave and the core wire so that you can twist the loose weave of the shield together into a “wire” and insert both the shield and the core into the holes on one side of the terminal; securing them in place by tightening the locking screws. It does not matter which hole which wire goes into, relative to the antenna pieces.

Attach the F connector of the coaxial cable to the antenna port on your TV and position the antenna end of the cable so it is pointing outside. My friend sits his on a piece of wood on top of a bar stool on his balcony. He says that he get the best results by pointing his antenna southwesterly.

Unlike analogue OTA signals, which can be almost received, digital OTA reception is apparently all or nothing. You will almost certainly need to move your antenna around to suit your location but it is important that it always sits or stands in a horizontal position.

Finally, you need to change the reception setting on your television from “Cable” to “Antenna”, or to “Air”, or whatever nomenclature your set uses (consult your manual if in doubt).

Beyond that, I think you can start channel surfing to see how many OTA signals your TV is now picking up. My friend says that he gets about six channels.

Six is admittedly a far cry from the 18 that are supposedly available in the Vancouver area. But frankly, you will feel a wonderful sense of accomplishment if the $2-$10 piece of low-tech that you cobbled together even picks up one channel!

And remember—not that I’m suggesting this will happen—if anything blows up, that is just a normal part of the learning process. Click the image to enlarge it.

From → Fairview, Televison

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