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

Snow

Horizontal bars rolling across the image

Vertical bars rolling across the image.

Ghosting

Herringbone pattern (diagonal lines across the image)

The bottom channels look fine, the top channels don’t.

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

Snow-

The snow is caused by inadequate signal strength at 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 of 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 ok there, add an amplifier before the splitter. Make sure you use a quality drive with good bandwidth (at least up to 1000 MHz). If you have digital cable or a cable modem, get an amplifier with a two-way return path to allow communication with the cable company. If the image looks bad on the brand, 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 entering the cable system. To fix this, disconnect the TV from all other system components. If the bars disappear, re-add the other components until the bars return. When you find the offending component, use a DC jammer 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 your audio system speakers.

Ghosting-

Ghosting is caused by the tuner receiving identical signals at slightly different times. It may be because your TV is receiving a local station that is broadcasting over the air and on the cable system at the same time. Be sure to use a 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 too. 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 setting with many 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 get this interference while modulating an A/V source on a certain channel, try changing to a different channel.

Bad upper channel reception –

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