Installation Instructions
Unpack the DCB101 from the box. Place the adapter in a suitable location close to the
source unit. The user will need to supply a patch cable from the source to the DC isolator.
Plug a cable from the DCB101 to the distribution amplifier. This will remove the DC offset
from the source Video and Audio channels. If the DC offset was the cause of the hum bar
issue, this should eliminate the problem. The unit may be secured to a wall with user
supplied screws.
Installation is complete.
HD
Distribution
Amplifier
HD Monitor
or Projector
DCB101 Typical Wiring Application
HD SOURCE
HD Monitor
or Projector
HD Monitor
or Projector
HD Monitor
or Projector
Breaking the DC path between the Video
Source and the Distribution Amplifier can
sometimes eliminate annoying hum bars.
Video Hum Bars
Causes:
So you just finished installing a new video distribution system and everything looks great.
Wait a minute, what is that green (or blue, or grey, etc.) bar that is slowly floating up through
the picture. If this sounds familiar, you are experiencing a video hum bar.
There are a couple of different causes for hum bars. If the source electrical power is too low,
the video devices may have a problem regulating their power supplies. This issue can be
compounded by sources that output DC offsets that place additional loads on the video
distribution system. A second source of the problem is differential ground voltage potentials,
which cause AC power to flow through the video cable grounds. This is commonly referred
to as “Ground Loop”.
The hum in the system might also be induced into the video cabling by being routed too
closely to an AC power cable.
Remedies:
1. The signal and AC power cables should never be bundled together.
2. Have a qualified electrician find and repair any defective AC outlets that may be causing
AC Ground Loop currents.
3. Use a distribution amplifier with isolated input grounds in order to break the Ground Loop.
4. If the video source has DC voltage on the video output, inserting a DC voltage blocker in
line can eliminate problems in the distribution network.
Specifications:
Connectors: 5 RCA in, 5 RCA out
Channels: 3 Video
2 Audio
Video Bandwidth: >300 MHz
Audio Bandwidth: 20 Hz to >1 MHz
Dimensions: 1.25” x 3.9” x 1.5”(2.3 including mounting tab)
Mounting Holes: 1.8” spacing, 0.15” diameter
NOTE: The three video channels may be used for three individual composite video signals if
desired.
