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Home Pre-Wiring, (CATV/Video)
An overview for CATV/Video home pre-wiring.
By Doug Moses, Jr. - October 21, 1996

Step #1 (Choose the grade of cable)

Coax cable is the standard medium used in the home for the transmittion of CATV/Video signals. This type of cable is usually 75 Ohm. There are many different grades of 75 Ohm Coax cable on the market today. The most popular grades are RG58, RG59, and RG6. When it comes to pre-wiring your home for the future you should select the best grade of Coax cable you can buy today. The standard used today for home automation and future CATV/Video needs is "Quad-Shielded RG6". This type of Coax cable is superior to the older RG58 and RG59 Coax cable standards used years ago. It is thicker in appearance and will produce a better quality picture in most cases.

Step #2 (Choose the type of connectors)

A connector is the item you use to attach the coax cable to your CATV/Video equipment. You will need to choose the type of connector appropriate for your equipment and grade of coax cable. The most common connector is the F Connector. Other popular types of connectors are BNC, TNC, and RCA. For standard TV and VCR connections you will need to use the F Connector. The two most common types of F Connectors are: screw-on type and crimp type.

Step #3 (Map out the cable runs)

When installing coax cable you should map out each run in detail before you begin pulling wires. The standard configuration for CATV/Video is to install two cables to the same outlet. One cable will carry the "Input" signal to the room and the other cable will carry the "Output" signal back to a central point. This type of configuration can handle almost any type of CATV/Video distribution.

Step #4 (Calculate dB loss)

In all CATV/Video setups there is a video signal source, (Antenna/VCR/etc.) and a video signal destination (TV/VCR/etc.). The longer the distance from the video signal source to the video signal destination the more video signal loss. A video signal's strength is measured it an amount known as dB. This amount can be calculated. You should attempt to compensate for the overall dB loss of signal in your installation. You should also use a tilt compensator for every 250 feet of single run RG6 coax cable. The following is a chart that details common dB loss.

                              dB
                           LOSS CHART
**************************************************************
*                   * Antenna thru UHF * CATV thru hyperband *
*       Part        *  @ 806 MHz       *    @468 MHz         *
*------------------------------------------------------------*
*      Cable RG6    *   5.9 dB/100ft   *   4.3 dB/100ft      *
*  Splitter  1x2    *   4.5 dB         *   4.0 dB            *
*            1x4    *   9.0 dB         *   7.5 dB            *
* Tilt Compensator  *   1.5 dB         *   4.5 dB            *
**************************************************************

                     Calculating dB Loss
                ******************************
                *    Cable dB Loss           *
                *  + Splitter dB Loss        *
                *  + Tilt Compenstor dB Loss *
                *  + Any Other dB Loss       *
                * -------------------------- *
                *    Total dB Loss           *
                ******************************

Step #5 (Design a CATV/Video distribution panel)

You should install all cable runs to a centrally located point. This method of wiring is know as the "Star" method. It helps in the isolation of wiring problems. It also allows you to build a single video distribution pannel for your CATV/Video system. Building a video distribution pannel usually begins by calculating the dB loss for each run and compensating the loss with video signal amplifiers. Next, you will add signal splitters and signal splitter/combiners for proper routing of the video signal to each location. The video signal strength should be equalized throughout the entire coax cable runs. Pre-built CATV/Video distribution panels can also be purchased rather than custom built. This is the preferred method for most installations.

Step #6 (Install gang boxes and drill holes)

Pre-wiring a home is the step in new home construction between the dry-wall phase and the electrical installation phase. If it is at all possible you should wait until after the electrician has completed their pre-wire installation before beginning your install. This way you will know exactly where all electrical wires are run. The first step in the actual pre-wire step is to install the gang boxes and drill holes for the cable runs. Make sure to install the gang boxes at the same height of electrical outlets and on opposite studs. You should drill holes no larger than 1 inch in diameter in the center of the studs. Larger holes will weaken the stud and expose the cable to dry-wall nails.

Step #7 (Install the cable)

Installing coax cable can be done in many ways. Here are just a few tips to consider when installing the runs of coax cable:

1. Make sure you do not install the coax cable directly on or near AC wiring. AC wiring can produce signal interference and noise. When you are forced to cross AC wiring, do so at 90 degree angles to the AC wiring.

2. Do not force the coax cable through the holes in the studs. Excessive wear could break the center wire in the cable.

3. Do not lay the coax cable in the valley of two studs. Minor settling of a home could cause the cable to break years down the road.

4. Try to attach your coax cable to the rafters of an attic rather than have it lie on the attic floor. Cables will become buried by insulation and can be hard to locate later.

5. Clearly mark each end of the coax cable. You can do this with colored cloth tape or labels.

Step #8 (Install the Face Plates and final touches)

This step should be accomplished after the dry-wall is up and the walls are painted. This phase requires attaching the connectors to the coax cable and installing the Face Plates. You may also have to touch-up the area around the Face Plates with cauk or spackle.

Step #9 (Testing the install)

Testing the install can be done in several ways. There are many different meters that can be used to measure signal strength. If you do not have any special meters you can always test the system with a TV and a VCR.

The Final word

This has been a quick overview of CATV/Video pre-wiring for the home. There are many other sources of information on this type of wiring. You can find these sources on the Web by using your favorite search engine and entering some key words. Some of these key words are: Home Automation, Coax Cable, RG6, RG58, RG59, Coax Terminator, Splitter, Splitter/Combiner, dB Loss, Tilt Compensator, Tap, etc...

You can also contact me (Doug Moses) via E-Mail at: dmoses@juno.com
or visit my home page: at Doug Moses' Home Page

The best company I have found in my area to install this type of coax cable has been AUTOMATED LIFESTYLE. This company installs Home Automation systems in the Dallas/Fort Worth Area. They are also a distributor for several other systems and equipment. You may contact them via E-Mail at:

AUTOMATED LIFESTYLE: mavrick6@ix.netcom.com