| [Connectivity] Comcast connection dropping/speed issues! 1) Location: Battle Creek, MI 49017
2) Problem description: The other day, my Comcast 12 Mb/s cable internet service began intermittently losing connection, even though all of the lights on the modem go on when it is reset, and even before it is reset. It will sometimes take only a few minutes before it starts working again, sometimes an hour or two. It will only show up as having a local connection, but no internet.
Ever since the first time this happened, we have been getting speeds of about 900 kbits, instead of the normal 20,000 kbits or higher that we were getting before. The strange thing is, the slow speed is very, very consistent. It is never more than 100 kbits different than the average (950 kbits), no matter what time of day it is.
3) It seems to occur at random, at least as far as I can tell. It has stopped working from 12 pm-4 pm, 8 pm-10 pm, and 3 am-4am, so I don't really see any pattern.
4) The modem is a Motorola Surfboard SB5101. Software Version: SB5101N-2.7.2.0-GA-00-NOSH
Hardware Version: 1
MIB Version: II
GUI Version: 1.0
5) We have 2 computers hooked up to a Netgear wireless router, which is connected to the modem. My laptop connects wirelessly, and the desktop is hooked in through an ethernet cable. The exact same problems occur on both computers, even if one is off and the other is on, and vice-versa. Connecting directly to the modem makes absolutely no difference at all, it has the same exact issues, and the same exact speed. So, I don't think the router could be an issue.
6) I occasionally scan my computer with AVG 8.0, as does my roommate. Neither of us have firewalls or anything else like that. Since this happens on both computers, and is so consistent, I don't believe this is an issue. |
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 tshirtPremium,MVM
join:2004-07-11
Snohomish, WA
kudos:3
 ·Comcast
1 edit | Hard to read the signals pic, but if that says
Power Level: 18.6 dBmv, your power is way too high and you'll need to call for a tech visit.
You do have enough leeway on the upstream power , that you might be able to pad it with a splitter or 2, but at some point when they adjust the line amp, you'll end up with the reverse problem.
Much better to let ComCast fix it themselves. |
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 dadkinsCan you do Blu?Premium,MVM
join:2003-09-26
Hercules, CA
kudos:18 | reply to Jsmith21
Yes, power level is bad |
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 EGThe wings of lovePremium
join:2006-11-18
Union, NJ
kudos:9 | Not at all disagreeing here that the Downstream Power level is way out of spec, but I just wanted to state that I have found the Motorola Surfboards to be some of the most forgiving of out of spec levels that I have ever seen.
At one time my SB5100 was seeing a Downstream Power Level of +22dB consistantly for over a year, and there was no evidence of any receiver front end R.F. saturation and never a hiccup ! Go figure. |
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 NyQuil Kid8f The Nyquil Kid
join:2001-01-06
Brick, NJ | reply to dadkins
Is there some online guide on being able to identify when power levels are good or bad?
Thanks in advance.
[8F] The NyQuil Kid |
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dadkinsCan you do Blu?Premium,MVM
join:2003-09-26
Hercules, CA
kudos:18 | said by NyQuil Kid:Is there some online guide on being able to identify when power levels are good or bad? Thanks in advance. [8F] The NyQuil Kid »Comcast High Speed Internet FAQ »What should my Signal Levels be?
Ballpark references
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Think outside the Fox... Opera |
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dadkinsCan you do Blu?Premium,MVM
join:2003-09-26
Hercules, CA
kudos:18 | reply to EG
Seen them way wack before myself, but if they are getting to the ~20 range, fluctuation or line noise could start causing issues.
SB5100s are very forgiving.
OP's does not look like a SB5100. 
--
Think outside the Fox... Opera |
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| reply to Jsmith21
OP here, we added a cable splitter to the cable going to the modem, and the levels have dropped a bit, yet, still the exact same speed and problems as before. Almost always 940-960 kb/s on speed tests, very rarely is it any higher or lower. The new signal levels are Frequency 543000000 Hz
Signal To Noise Ratio 38.6 dB
Power Level 15.9 dBmV |
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walk
join:2009-03-06
Petaluma, CA | 15.9 is still WAYYYYY too high.
Add another splitter (or 3) if you want immediate results.
THEN ALSO call Comcast and have a tech come out and adjust the levels.
It should NEVER be any higher than +8.
Ideally more like +0. |
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NyQuil Kid8f The Nyquil Kid
join:2001-01-06
Brick, NJ | reply to dadkins
Thank you - will check it out.
[8F] The NyQuil Kid |
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ats
join:2008-11-14
Vallejo, CA
kudos:1 | reply to Jsmith21
levels:
red -bad
yellow - marginal
green - good |
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EGThe wings of lovePremium
join:2006-11-18
Union, NJ
kudos:9
1 edit | reply to dadkins
Re: [Connectivity] Comcast connection dropping/speed issues! said by dadkins:Seen them way wack before myself, but if they are getting to the ~20 range, fluctuation or line noise could start causing issues. I would think that downstream "line noise"/ingress would be an more of an issue with weak rather than strong downstream power levels ?
I would be more concerned with the saturation of the front end of a modem's receiver which will result is distortions.SB5100s are very forgiving. OP's does not look like a SB5100. Yes, but I have found that other Surfboards that share similar chipsets have similar benefits. |
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