Owens Corning
Extend Your Television System with an Antenna
It's not unusual to find a TV set tucked in a corner or sitting on a shelf in more than one room of the average American household. You can get improved reception and eliminate those pesky rabbit ear antennae by hooking 2 TV sets to your outdoor antenna. This sounds more complicated than it is. The project involves installing a hybrid splitter, which allows you to run 2 sets off of a single outdoor antenna. Your local hardware store has everything you need.

Depending on the age of your present antenna system, the lead in wire running from the antenna to your TV could be either a flat 300 ohm twin lead wire or a round 75 ohm coax cable. Either system works well if it is in good condition. In fact, there is actually less signal loss per foot with the older 300 ohm twin lead wire. The biggest problem with the twin lead wire is that it is not shielded and can pick up noise, which you see as interference on the TV screen from nearby house wiring. This can be pipes or other metal objects it might run parallel to. For this reason, coax cable is preferred for running around the house to different TV sets. Most of the modern splitters, filters, and amplifiers are also designed to work with this type of cable.

It is easy to make the switch from a flat wire system to coax. There are several different types of transformers that allow you to connect 75 ohm coax cable to a 300 ohm flat lead line. The best place to do this is at the antenna, but if you don't relish roof work you can install the transformer anywhere in the line. Purchase an outdoor transformer if connections will be made outside. From this point on you can use coax cable.

For this project we explain how to make up the cables and where to install the splitter. The logistics route depends on many variables, mainly where the sets are located in your house. You'll have to do some scouting around or under your house to decide the best route to get the cable from set to set. One of the easiest routes we know is running the antenna down into the basement or crawl space first, and from there split the cable to hook up to several rooms.

TV antenna and cable TV installers think nothing of running the coax cable around the outside of a house. They take the direct approach and punch through the wall wherever an outlet is needed. This might provide the easiest access, but it's not exactly the most attractive one to have the outside of your house look like it's wrapped in wire. We think it's worth the effort to try to run the cable inside the house.

Spend some time walking around your house and looking at the wires already there. It's not a bad idea to make a mental note of which wires (telephone, utility lines) run where.

Look at the antenna and follow the wires to see where they go. If you have twin lead wires coming down from the antenna, install an indoor/outdoor 300 ohm to 75 ohm matching transformer on the end of the twin lead. From then on use 75 ohm coaxial cable.

Coaxial cable comes with a male F-screw fitting at each end. As soon as you cut the cable to the length needed, you have to install a fitting on the other end to connect the cable to the splitter or TV set. Installing a F-type connector is easy; it just takes a little patience. You'll find a wiring diagram similar to our illustration printed on the connector package.

Before you begin preparing the end of the cable to receive the F-connector, slip the ferrule (small ring) on the cable and slide it down the wire so it's out of the way. After the connector is in place, crimp this ferrule over the fitting to lock it in place.

Next, strip 1/2-in. of the outer insulation off the end of the cable. Unravel the braided wire or foil surrounding the center conductor and bend it back over the outer insulation. Trim 3/8-in. of the insulation surrounding the center conductor off to bare the wire. Slip the fitting over the center conductor and push it as far as it goes. Check that the outer braided wire is still folded back over the outer insulation so you can work the body of the fitting under the braid. Keep twisting the fitting to help it slide under the braid until the braided wire is in contact with the front of the fitting. Trim away the excess wire but be careful not to cut through the outer insulation. Then slip the ferrule over the fitting and crimp it tight with a cable crimping tool. This sounds involved, but it really takes just a couple of minutes once you get the hang of it.

You don't need much help installing the splitter. It's as simple as attaching the lead in cable for the antenna to the terminal marked IN on the splitter. Connect the other cables that will lead to the TV sets to the terminals marked OUT.

At the back of each television set, you should connect the end of the coaxial cable to the IN terminal of transformer/splitter. Attach a short piece of flat 300 ohm wire to the screw terminals marked VHF on the splitter, then attach the other end to the VHF antenna terminals on your set. Do the same on the UHF side of the splitter and the set is ready to use.

You'll need a crimping tool and the following items:

1 indoor/outdoor matching transformer 300/75 ohm

1 50-ft of RG59U coaxial cable

1 box of male F-screw type coax fittings

1 75 ohm input/2 75 ohm outputs - hybrid splitter

2 transformer/signal splitter - 75 ohm input/300 ohm outputs

Best Tips

1. A hybrid splitter installed in the lead in wire from a roof-mounted antenna allows 2 TV sets to share the antenna.

2. To prepare coaxial cable to receive an F-type fitting, remove 1/2-in. of outer insulation, then fold back the braided outer conductor. Remove 3/8-in. of the inner insulation to bare the inner conductor.

3. Slide the ferrule onto the cable, then push the fitting body on the end of the cable. Twist the fitting to work it under the outer braided conductor.

4. Slide the ferrule up snug against the fitting and crimp it tight by placing the ferrule in the crimping tool and squeezing down hard on the handles.

written by the editors of HouseNet
Copyright HouseNet, Inc.

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