When two or more devices are connected to a common ground through different paths, ground path noise or a ground loop can occur. This is actually quite common in home theater systems, even those that are well designed. The result of a ground loop is audio hum and/or horizontal bars in the TV picture. Disconnecting coaxial connections between components eliminates the hum or interference. If "beefing up" conventional ground connections and establishing solid ground points in your cable system does not resolve these problems, then a CableTVamps Ground Isolator is the most reliable way to fix it.
A Comcast technician was able to fix some video banding with a new outdoor ground on their CATV lines. However, while it did make all of the banding go away, there was still some 60Hz ground loop buzz. I gave up on browbeating the tech into tracking it down.
After a bunch of research, the Jensen VRD-1FF seems to be the top-of-the-line solution for CATV isolating transformers. On the low-end, there are various RadioShack transformer models without CATV coaxial connectors that you could rig or two antenna 75-to-300 ohm baluns which could be used back to back (if they have isolated shielding--most cheap ones don't). That puts the Viewsonics model in the middle.
This model worked great for me to remove any trace of 60Hz hum without messing up on-demand or any channels on my digital Comcast.
You may want to be careful not to damage the isolator by making sure the center pin/wire on your coaxial F-connector doesn't extend too far out of the cable.
It completely eliminated the 60Hz line hum from my audio system that began the instant I plugged the TV's HDMI into the DVD player. I'm completely satisfied. I didn't experience any signal strength drop. If you do, you can always get a line amplifier but wait to see if the isolator causes a drop first. Don't forget to order a 75 Ohm coaxial cable male-to-male connector if you want this to be an "in line" unit as it's female on both ends. I do wish it wasn't made in China, as it is, but that's another issue entirely.
No comments:
Post a Comment