voltage on co-axial cable

[bmuse61]

I had a service call where the customer was complaining of having a bad picture on the lower end channels on all three televisions he had. Upon investigation found that when the cables where removed from the splitter there was 49 volts to ground from the braid as well as the center core. The voltage would go up or down as I plugged in the television, vcr, cable box. When the equipment was unplugged from the receptacle voltage dissapeared. There was never any voltage on the home run cable, just on the cables feeding out of the splitter. Both receptacles are on the same circuit and have been checked for proper grounding in the box and the conductors in the breaker panel were tight. I grounded the splitter but this did not change anything. Can anybody shed some light on how voltage is being induced into the co-ax? Thanks

 

[hbiss]

Re: voltage on co-axial cable

Your voltage readings are erroneous because of the high impedance meter you are using. Many TVs will have leakage which is of no consequence. The proper way to measure for abnormal leakage is to place something like 1k across your test leads. If you measure a voltage then, then you have a problem with the set. I absolutely doubt though that this is the cause of the problem you mention.

As for the "bad picture", well THATS certainly descriptive! I have no idea what it looks like, if this is an antenna, an antenna with an amplifier, CATV, sat receivers... you get the idea. Give me some more info and maybe I can help.

-Hal

Ahh, I just reread your question and see that you do mention a cable box so I guess that this is CATV. What I would do is connect a TV to a point closest to where the service enters and see what it looks like. I'll bet the problem is with the cable company. As a matter of fact, why don't you let the cable company handle this?

-Hal

[ May 22, 2004, 01:03 AM: Message edited by: hbiss ]