Possible Power quality problems with cable company signal 1

[MrJam]

Recently A cable company ask use to do some power monitoring at a few of there subscribers houses. Apparently, their having trouble with the television picture tiling, or pixelating in these houses. They have tried everything they can think of. The company thought that it might be a power quality problem. I thought maybe ferrite cores on the coaxial cable might help. We are setting up a Hioki 3196 on the power lines coming into one of the houses to give us some insight into the problem. Does anyone have any possible solutions

 

[peebee]

A missing or bad ground can DEFINITELY cause problems. The grounded coax shield is the reference for the signal. If the power system ground is at a different potential, that will result in noise on the signal.

On audio equipment connected to the cable box, that noisy ground can manifest as a 60Hz hum. But even if it's not audible, it can still cause problems with the video reception too.

One quick test for grounding problems -- if you take one of those 2-prong receptacle adapters and use it to lift the ground on all of the AV equipment and all the problems dissapear, then it's almost definitely a grounding problem. Yes, that's a code violation and a safety hazard, so don't leave it that way.

Frankly, I'm shocked that the cable company wouldn't have checked that before hiring someone to check the power quality.

 

[mc5w]

What also gets me is that when a residential service has its neutral go open circuit, the neutral current does not burn up the cable TV line. The shield is about equivalent to #14 copper wire. The last time a customer had this happen was in a neighborhood that uses wells for water supply and there are no gas lines.

Using automotive jumper cables to hook up the copper water line that came in from the well to the electrical service ground improved voltage regulation until I got back from the electrical supply house with a temporary neutral for Ohio Edison to hook up and some stuff to permanently bond the well pipe and casing to the electrical service.

Oh yeah, when I one time put in a new well pump for a female friend I found out ( before reapplying water pressure ) tha her ex-husband had installed some CPVC water pipe WITHOUT solvent cement. If I had not accidentally knocked a pipe joint loose I would have had a slapstick comedy as the new submersible pump would have provide more water pressure than the old jet pump.

And, a few weeks ago I found out that the reason why a gas furnace never really worked right was because there was a piece of foam rubber pipe insulation INSIDE the gas line!

Mike Cole

 

[itsmoked]

It is amazing more disasters don't occur with the abject stupidity that abounds.

A local car dealership (Hummers) was being remodeled. The plumbers disconnected a gas line; 1-1/2". Gas was coming out so they fixed this by stuffing in a rag. A few hours later.. The building shattered. I think there was even a fatality. I drove by a week later the walls that were still present were severely bulged glass surrounded the place. Stupid-incarnate.

So a missing cable ground? Sure.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[waross]

Code requires the sheild to be grounded.
Code DOES NOT require the sheild to be grounded at both ends.
Grounding a shield at both ends often introduces other issues. Sometimes these issues are serious.
Respectfully.

 

[dinkelja]

I ground cable tv connections only at the demarc point, to the the building electrical panel ground (residential water pipe usually). Beware, I have been "shocked" before by cable connections to old tube tv's due to a lack of polarity on the plug, and a part of the chasis becoming hot.
Investigate what type of wiring runs throughout the building / houses: RG59, RG6, RG6 Quad Shield? I notice problems with digital cable and the lossy RG59. Finally, always use high quality, 1000 MHz DC PASSING splitters. Have you tried the comm. engineering forum?
Good Day.