How to fix video problems

Few things can be as frustrating as imaging problems. You have your system ready to go, flip the switch and WHAM! One or more channels look terrible. The good news is that most video problems can be traced to a few causes. Most of the problems are understood as follows:

Snow

Horizontal bars rolling across the image

Vertical bars rolling across the image.

Ghosting

Herringbone pattern (diagonal lines across image)

Bottom channels look good, top channels don’t.

These six are the main symptoms you will encounter when viewing video problems. Fortunately, most are fairly easy to fix.

Snow-

The snow is caused by inadequate signal strength on the tuner. It is usually caused by:

1 Split the signal too many times.

2 A weak signal from the antenna or cable company

3 A very long cable run

If the signal is zero on all your TVs, especially if you have more than 4 TVs, you probably need an RF amplifier. Check the force at the mark (service entrance). If it’s okay there, add an amp before the splitter. Be sure to use a quality drive with good bandwidth (at least up to 1000 MHz). If you have a digital cable or cable modem, get an amplifier with a two-way return path to allow communication with the cable company. If the picture looks wrong on the mark, contact the cable company.

If it’s bad on only one TV, you may have a bad cable between the splitter and the TV, or a very long cable run. You can amplify just that run.

Horizontal Rolling Bars –

Horizontal rolling bars are caused by DC power input into the cable system. To fix this, disconnect the TV from all other system components. If the bars disappear, add the other components again until the bars return. When you find the offending component, use a DC blocker to remove the DC power path to the system.

Vertical Sway Bars –

Vertical rolling bars are caused by AC power entering the cable line. The best solution for this is to use a ground switch. A ground switch removes the electrical connection between the TV and the cable system. A ground switch is also the main solution for a hum in the speakers of your audio system.

Ghosting-

Ghosting is caused by the tuner receiving identical signals at slightly different times. This may be because your TV is receiving a local station that is broadcast over the air and on the cable system at the same time. Be sure to use good quality RG-6 coaxial cable and good compression fittings. Replace any low-quality cable splitters or combiners with high-quality units. Make sure they are tight as well. This will also cure another cause of ghosting, signal reflection within a poor cable.

Ghost images can also be caused by multipath interference in an antenna system. This is especially true in an urban environment with lots of hills and tall buildings. To combat this, use a highly directional antenna aimed directly at the desired station.

herringbone pattern –

A herringbone pattern is caused by radio frequency interference from other stations transmitting on the same or adjacent channels, strong radio signals, computers, etc. Another common cause is being equidistant from two transmitters operating on the same channel.

In short, this can be caused by almost any type of RF radiation at the correct frequency. The heavy shielding found in high-quality cables helps combat this. If you experience this interference while modulating an A/V source on a certain channel, try switching to a different channel.

Poor upper channel reception –

Poor upper channel reception is due to poor signal on the upper channels. Use an amplifier with a tilt compensator that allows adjustment of the upper channels in relation to the lower channels. This will avoid overloading the lower channels and provide sufficient gain for the upper channels. Also, verify that all components in the RF system are rated at least 1 GHz and that RG-6 or RG-6 quad shield cable is being used at all times.