General Hardware and Software

[jbotka]

I have had this problem with Comcast for at least 4 years. Here is a brief description. I have a huge amount of noise on my comcast line coming in the house. So bad that I cannot use my stereo. It is a low hum and at times I can pick up AM 1000 through my speakers. When I disconnect the comcast cable from the house the problem is gone. I have had dozens of techs out to my house over the years to try and fix it. They have replaced every wire, splice and cable box in the house with no results. I have been told by some techs that the problem is the noise on the line coming in my house. But they cannot or will not fix it. I am an electrical engineer and have a solid understanding of electronics and cannot get in touch with anyone who has the skills to solve the problem. I have paid them a good amount of money for the service over the the years and I believe they have a very good product when it works. I would love to change service but that would require tons of work on my end to switch over and comcast has the fastest internet speeds. I need that since I work from home. I am not looking for any monetary compensation I just want the problem fixed. It is very obvious that it is with the comcast line coming into my house. I have been told that by the technicians. I have been told that they were going to escalate my problem but nothing has happened to date. The numbers they gave me to call and follow up have been disconnectecd. Their normal 800 number just gets me in the same loop. I call. They send out a tech. It is determined the problem is on the line coming into the house. They tell me they are going to work on it. They leave. Nothing more happens.They document nothing in their computers for future calls. It all starts over again. Going on 4-5 years of this now.
Not sure what else to do.
Can you please help me?
Thank you very much.

[JamesR]

If you are a Double Eagle let suggest an old book titled "Grounds, Grounds and More Grounds". Think about a Single Point ground. Three wire to Two wire adapters are evil! Go through and hook up all the ground lugs. A floating ground functions as an antenna. :-) If you're picking up a radio station, then your coax sheilds are not getting down to Earth Ground. Good Luck with it.. please post back with your reslution

[EG]

Agree on a single point/floating ground problem but I did not want to advise an "electrical engineer" of this. The coax grounding block/demarc/entry point should be *bonded* with the electric meter grounding. Perhaps there is a problem with the grounding of the home's electrical system ?

[jbotka]

Will look into that and post with my results in a few days. I mainly work on high voltage electrical systems where noise is less of a problem. Usually we are the guys causing the problems for the low voltage systems.

The house is 6 years old and the wiring is good. Installed a deeper higher quality ground rod on the house and that made no difference. So that was eliminated as a problem. From what I can tell so far is when the comcast line is connected it is amplifying existing noise in the system.

We did find some metal shavings in one coax connector. Replaced wire. No difference.

So I have to do a component by component test to isolate a troublesome piece of gear. Could take a while but will post my results. It may help someone out there.

Thanks for the responses. Every bit of info and suggestions help.

J

[JamesR]

Thanks for wapping back around it will be interesting to see how this works out for you.

[shveazzy]

use a 1000 mhz filter on your cable line between the box and wall plate or could possibly be a grounding issue 

[jbotka]

Ok. Cannot isolate a noise issue in my equipment. Have removed all equipment one item at a time and the noise is still there. Swapped out wiring (power and signal). Used different outlets on the other 120 phase. Same thing.

So here is my fix for now. Installed a Jensen ISOMAX filter on the incoming cable line. Noise is gone.
But the signal strength is very low. (Low to begin with -8db to -11db -- they wont fix that either)

So now I installed an 8db amplifier (Channel Vision) on the line after the filter. Now I am at +6db to +8db. Everything is working for now.

Have spent about $140 on the filter and amplifier. Nice to know that Comcast line issues are not a priority.

On my own figuring it out. Hey the way to get a job done right is doing it yourself.

At least I think I have a handle on it now. Too bad their techs cant figure it out. Not one has been able to figure it out to date.

The original problem is still there (Noise and Low Signal Strength). Any ideas on how to get them to fix it?

Since they do not keep notes on service visits I start from square one everytime they show up.

Thanks for your advice and help everyone.

J

[JamesR]

Thanks for posting back with your reslution. What does your SNR and upstream Power look like?

[JamesR]

Thanks for posting back with your progress. Whatdoes your SNR and upstream power look like?

[EG]

That's not a fix, it's just a "band-aid"...

[Schwaben]

Hi J,

Did you ever get this fixed? I have the same problem. Brand new house, new wiring, terrible noise from speakers that disappears if I unplug the HDMI wire from the back of the Comcast box. Three different Comcast techs came out, each promising to bring a supervisor with him; they came, but no supervisor, and none could fix the problem. Finally, the last one gave me the email and phone number of his supervisor--Michael Eugea. I email and called him; he said he would come out on a Tuesday, then, after I stayed home from work waiting for me, he simply stood me up. Does not respond to emails or phone messages. 

Please let me know what you figured out--I am not an electrical engineer!

Thanks.