Wire Conversion - Structured Home Wiring

Combining Composite/S-Video to Coaxial Cable using a RF Modulator:

RF Modulators can convert Composite or S-Video inputs into Coaxial output. Most RF Modulators will only output the video on Channel 3 or 4, but some actually let you pick any channel up to 125. Both Composite and S-Video cables are limited in how long the cables can be. Coaxial cable doesn't have this problem and it is much cheaper.
If your television only has one Coaxial input and it is already in use, then you can use an A/B switch to switch between 2 different Coaxial inputs. Another alternative is to combine both Coaxial wires. See Combining Analog TV Signals over Coaxial Cable for more information. below for more information.

Splitting Composite Signals:

Splitting Coaxial wire is as simple as using a Y RCA splitter. To split a audio/video signal, you will need 3 splitters: one for the video (yellow), one for the right audio (red), and one for the left audio (white). There is some signal loss when splitting composite wire or when running composite wires a long distance.

Splitting Coaxial Signals for Cable/Antenna:

Splitting Coaxial wire is also simple. You can find splitters that will split into 2, 4 or more lines. Using a splitter will degrade the signal strength, and sometimes a cable booster/amplifier will be required. To make things easy, there are all-in-one booster/splitter units.

Splitting Coaxial Signals for Satellite:

Splitting cable for satellite is much more complicated. A multiplexer is required to split a satellite signal. A single satellite dish may produce 2, 3, 4 or more coaxial outputs, each one carrying a different signal. You may even have multiple satellite dishes to get all the channels you want. Simply splitting one of these wires for 2 different televisions will not work. A multiplexer will take all of the satellite wires and produce additional outputs. The capabilities of a multiplexer are written as 2x4 (converts 2 wires into 4) or 5x8 (converts 5 into 8). When purchasing a multiplexer, make sure it will work with your service (DirecTV / DishNetwork), and realize that some of the inputs may be dedicated for a local channel antenna or for international satellites and might not suit your needs.

Combining Analog TV Signals over Coaxial Cable:

Under special circumstances, coaxial cables can be combined. Say you have a Coax feed from a RF Modulator with a signal only on Channel 3. You also have an antenna/cable feed and there is no station on channel 3. Then, you can theoretically combine the 2 coaxial feeds into 1 by using a Coaxial splitter backwards. If you are going to attempt to do this, you should get a RF Modulator that lets you pick any channel. Just because there is no station on a given channel doesn't mean that there isn't any noise on that channel. You may also need to get a filter to clean/remove the noise from the antenna/cable feed to be able to properly combine the Coaxial feeds. The filter will cost more, but combining the feeds is better than having to manually use the A/B Switch to change between inputs. Note: Satellite signals can never be combined with anything.

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