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Comcast - Motorlla SB5100

What did Comcast suggest? If you're renting the modem, couldn't you just exchange it for another one?

I'm not really sure about you signal levels but they don't look that good to me, although they are within range. Here is an FAQ about the different levels:

»Cable Modems and Wiring Issues »What kind of signal levels do I want on my cable modem?
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TH ~ NE ~ EPN ~ NC ~ TD

The only thing Comcast suggested was that they could send someone out to check the line. If that would require a fee then I don't want to pay for it as I have a feeling they will just blame the issue on your end and charge you for it.

Would you like this thread moved over to our Comcast Forum to see if you can get some help there? Let us know.

I guess it would help to move the topic to the Comcast forum.

I also removed my junk 3-way splitter and the downstream power level went from -10 to -3. The only other thing that changed was my Upstream power level. It went from 45 dBmV to 36 dBmV.

One other question I have is with the cable splitter. I've seen some Antronix splitters with the range from 5MHz - 1GHz with a number next to it of -5.5db. Does that mean the loss of the signal so if I were to replace my old splitter with a new one the number I have now was -3 would go to -8.8? I guess that would still be better then what I had but not by much.

I went outside to check the line and from my handoff, I have a pass through near my electrical meter and then the Antornix splitter in the back of the house. Is there any way I can ask Comcast to check the power level and see if it is within specs at the handoff without getting charged for it?

If your downstream power is currently -3 dBmv, upstream power is 36 dBmv and downstream signal/noise ratio is 35 dB, then your signals are fine, at least at the time you measured them. Impossible to tell from one post whether the levels are changing, of course. Try asking Comcast if they see the levels varying around the time that the modem is losing sync.

To answer your question, yes, the modem itself could be intermittent. If you're renting the modem, try exchanging it. If you own the modem, try renting one for a week or two, just to see if the problems clear up.

Problem cleared up after the issues they had over the weekend. I guess I noticed it was brewing as I'm usually connected with SSH sessions and would know this happens more than someone who was internet browsing.

Well I spoke too soon. I'm still getting the same issue. I checked my signal on my modem and the downstream power level was at -14 dBmv today. The -3 dBmv was with one of my splitters missing which I need and was there before having this issue. The reading with that splitter was showing -10 dBmv a few days ago. Now the same configuration is showing at -14 dBmv with no changes and this started yesterday. Does this look like there is a signal issue with my handoff from Comcast?

Ok I did a little bit more troubleshooting. I had my cable for the modem hooked up to the furthest output port on the splitter. When I moved it in to the middle it went up to -12 and then to -9 on the closest to the input. I'll see if that helps.

Guess you tried changing the cable from the splitter to the modem?

Yep tried that too but there was no change. I'm still getting the drops. I have no idea how I'm going to debug this issue since it is sporadic. I'm going to disconnect my router and work through the day tomorrow and see if I get the same disconnects. If I do then I have a problem either with my cable modem or my handoff. Do the cable modems usually flake like this when they are failing? I would think that the modem either works or it doesn't.

Ok more troubleshooting...I hooked one of my computers directly to the cable modem and still had a drop for about 45 seconds to a minute. The issue is either my modem or something on Comcast's end. Will Comcast charge me to have the line tested out? My downstream power level is at -10 with a noise of 35.

I do not think that they charge you if in fact they find the problem is on their end!

reply to npolite
the easest test for you is to replace the cable modem. If it is your modem you could try renting one for a month ($3-5) or could call for a tech visit, and they have tools to determine the signal at the drop. if the signal at the drop is good, and the house wiring is good they will likely offer you a rental modem, instead of charging you.

reply to npolite
I may be out of line here, but is it really worth all of the hassle you are going through to save a POSSIBLE trouble call fee? In my area, a data trouble call costs a flat $39. The phone company charges $110 for the first hour and $50 for every half hour after plus materials for home wiring issues.

I mean, you say you have had the same setup for 10 years with no problems. Things can go wrong after 10 years and the techs are the ones who have the correct equipment to divide and conquer efficiently.

By the time you are done replacing cables and splitters, assuming you do it correctly with the correct materials, you are going to have invested money and time equal to or greater than what they would charge for a service call. And most areas offer some sort of wire guard plan for a fee that is significantly lower than any other medium (sat or telco). After it is all said and done, you'll likely end up calling them anyway. And if they find the problem outside, you have done all of this for nothing.

Again, this post is not to be argumentative, but this is another way to look at it. If I were in your situation, I would leave it to the professionals. But that's me.