View Full Version : Video Hum

Dave Carlson
10-06-2005, 04:49 PM
I am a new engineer at a small local cable access station. We have video hum, and a stationary transparent bar in our signal. I have eliminated most of the hum (v-roll). It was inductive. I still have the stationary horizontal bar in the video, on both channels, both in house and on air. I think it may be related to the fact that the video components are split on at least two of the three legs of the 3-phase power, and that the grounds in the building are notoriously bad.
Any ideas?



10-06-2005, 09:26 PM
I'd get ground fault checking powerstrips to see, or maybe run them through a power filtering UPS unit. Also check for any running motors (aka Fans) near cables. I was video capturing and had a fan sitting on my cable line and it caused waves in the video. Also make sure speakers are sheilded and not next to video sources, can cause anomilies too.

10-07-2005, 06:59 AM
Also, if you have a cable TV feed connected to any of your equipment, you should try a ground blocker. It's amazing how the ground potential from the Cable RF system can bleed into your entire video system.


Try #63400

Dave Carlson
10-07-2005, 11:17 AM