Get Some Video Answers
Use this form to contact us for answers about home theater, distributed video, room
acoustics, or anything else you may need information on.
Use this form to contact us for answers about home theater, distributed video, room
acoustics, or anything else you may need information on.
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How to Troubleshoot Video Problems in Your Home Theater or Multi-
Room Video System
Few things can be as frustrating as picture problems. You get your
system all ready to go, flip the switch, and WHAM! One or more
channels look terrible. The good news is that the majority of video
problems can be traced to just a few causes. Most problems are
comprised of the following:
Snow
Horizontal bars rolling though the picture
Vertical bars rolling through the picture
Ghosting
Herringbone pattern (diagonal lines through picture)
Lower channels look fine, upper channels are not
These six are the main symptoms you’ll find when seeing video
problems. Thankfully, most are fairly easy to fix.
Snow -
Snow is caused by inadequate signal strength at the tuner. It’s usually
caused by:
1 Splitting 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 snowy at all your TVs, especially if you have more than
4 TVs, you probably need an RF amplifier. Check the strength at the
demark (service entrance). If it looks good there, add an RF amplifier
before the splitter. Make sure to use a quality unit with good
bandwidth (out to at least 1000MHz). If you have digital cable or a
cable modem, get an amplifier with a bidirectional return path to allow
for communication back to the cable company. If the picture looks bad
at the demark, contact the cable company.
If it is bad at only one TV, you may have a bad cable between the
splitter and the TV or a very long run of cable. You can amplify just
that run.
Horizontal Rolling Bars –
Horizontal rolling bars are caused by DC power getting into the cable
system. To fix it, disconnect the TV from all other components in the
system. If the bars disappear, add the other components back in until
the bars return. When you find the offending component, use a DC
blocker to eliminate the DC power path to the system.
Vertical Rolling Bars –
Vertical rolling bars are caused by AC power getting on the cable line.
The best fix for this is to use a ground breaker. A ground breaker
eliminates the electrical connection between the TV and the cable
system. A ground breaker is also the main fix for a hum on your audio
system’s speakers.
Ghosting –
Ghosting is caused by the tuner receiving identical signals at slightly
different times. It can be caused by your TV receiving a local station
broadcasting over the air and via the cable system at the same time.
Make sure you are using good quality RG-6 coax cable and good
compression fittings. Replace any low quality cable splitters or
combiners with high quality units. Make sure they are tight also. This
will also cure another cause of ghosting, signal reflection inside a
poor cable.
Ghosting can also be caused by multi-path interference on an
antenna system. This is especially true in an urban environment with
lots of hills and tall buildings. To combat this, use a very 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 channel or adjacent channels,
powerful radio signals, computers, etc. Another common cause is
being equidistant from multiple transmitters operating on the same
channel.
In short, this can be caused by just about any sort of RF radiation at
the correct frequency. Really great shielding found on high quality
cables helps to combat this. If you are getting 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 caused by poor signal strength 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 overdriving the lower channels while
providing the upper channels with enough gain. Also, check to see if
all components in the RF system, such as splitters and taps, are rated
to at least 1GHz. It's also important that good quality RG-6 or RG-6
Quad shield cable is being used throughout the system for any RF
application.
If these don't help eliminate your video problems, shoot us an email.
Always remember, loose fittings make for bad video.
Room Video System
Few things can be as frustrating as picture problems. You get your
system all ready to go, flip the switch, and WHAM! One or more
channels look terrible. The good news is that the majority of video
problems can be traced to just a few causes. Most problems are
comprised of the following:
Snow
Horizontal bars rolling though the picture
Vertical bars rolling through the picture
Ghosting
Herringbone pattern (diagonal lines through picture)
Lower channels look fine, upper channels are not
These six are the main symptoms you’ll find when seeing video
problems. Thankfully, most are fairly easy to fix.
Snow -
Snow is caused by inadequate signal strength at the tuner. It’s usually
caused by:
1 Splitting 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 snowy at all your TVs, especially if you have more than
4 TVs, you probably need an RF amplifier. Check the strength at the
demark (service entrance). If it looks good there, add an RF amplifier
before the splitter. Make sure to use a quality unit with good
bandwidth (out to at least 1000MHz). If you have digital cable or a
cable modem, get an amplifier with a bidirectional return path to allow
for communication back to the cable company. If the picture looks bad
at the demark, contact the cable company.
If it is bad at only one TV, you may have a bad cable between the
splitter and the TV or a very long run of cable. You can amplify just
that run.
Horizontal Rolling Bars –
Horizontal rolling bars are caused by DC power getting into the cable
system. To fix it, disconnect the TV from all other components in the
system. If the bars disappear, add the other components back in until
the bars return. When you find the offending component, use a DC
blocker to eliminate the DC power path to the system.
Vertical Rolling Bars –
Vertical rolling bars are caused by AC power getting on the cable line.
The best fix for this is to use a ground breaker. A ground breaker
eliminates the electrical connection between the TV and the cable
system. A ground breaker is also the main fix for a hum on your audio
system’s speakers.
Ghosting –
Ghosting is caused by the tuner receiving identical signals at slightly
different times. It can be caused by your TV receiving a local station
broadcasting over the air and via the cable system at the same time.
Make sure you are using good quality RG-6 coax cable and good
compression fittings. Replace any low quality cable splitters or
combiners with high quality units. Make sure they are tight also. This
will also cure another cause of ghosting, signal reflection inside a
poor cable.
Ghosting can also be caused by multi-path interference on an
antenna system. This is especially true in an urban environment with
lots of hills and tall buildings. To combat this, use a very 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 channel or adjacent channels,
powerful radio signals, computers, etc. Another common cause is
being equidistant from multiple transmitters operating on the same
channel.
In short, this can be caused by just about any sort of RF radiation at
the correct frequency. Really great shielding found on high quality
cables helps to combat this. If you are getting 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 caused by poor signal strength 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 overdriving the lower channels while
providing the upper channels with enough gain. Also, check to see if
all components in the RF system, such as splitters and taps, are rated
to at least 1GHz. It's also important that good quality RG-6 or RG-6
Quad shield cable is being used throughout the system for any RF
application.
If these don't help eliminate your video problems, shoot us an email.
Always remember, loose fittings make for bad video.
1TouchMovie.com
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