 DrDrewSo that others may surf.
join:2009-01-28
SoCal
kudos:9
4 edits | reply to pbarrow
Re: [HSI] Charter Subs said by pbarrow:I Most of the Phone tech support people don't know jack about Upstream SNR or even how to check it. You need to insist that they put your modem on a Watch for several days and check the CMTS history for your Upstream SNR. The min is 22db and if it drops to 22db and below you will have speed and performance issues and at worst dropped connections. The screenshots he had posted previously showed an upstream SNR of 29-32 dB. The reading were taken every 2 hours for several days.
Of course that doesn't show upstream BER, which directly impacts the likelyhood of T3s.
Things like CPD kill upstream SNR, while something like impulse noise will impact BER with little effect on upstream SNR. Either one will cause problems for upstream modem traffic.
Meanwhile something like upstream signal reflections, hum modulation, or ground loops on his home wiring can cause upstream signal problems and T3s for him and no one else. It wouldn't even register on the CMTS since those are aggregate upstream readings from all the modems on the port.
But you're right most phone tects and service techs sent to your home know nothing about those things and rarely have the tools to find them. |
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 koma3504AdvocatePremium
join:2004-06-22
North Richland Hills, TX | Meanwhile something like upstream signal reflections, hum modulation, or ground loops on his home wiring can cause upstream signal problems and T3s for him and no one else. It wouldn't even register on the CMTS since those are aggregate upstream readings from all the modems on the port.
Could you explian this a a little more??
So that I might check for such.
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† Koma †
If YOu Don't Think It's Possable!! It's Acually A Reality!!The best way to predict the future is to invent it. Alan Kay!!
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 j_r0kk
join:2009-03-31
Manhattan, KS
kudos:2 | pbarrow,
don't be too quick to jump the gun on an upstream SNR issue. You're shooting darts in the dark without seeing any actual numbers. I'm not disagreeing, but you shouldn't throw stuff out there like that without factual information.
koma3504,
If I were in N. Richland Hills I'd come over there and fix your problem for you. However, I'm not so I can't. With that being said, you will unfortunately need to call in. Ask to speak to a supervisor this time. There is obviously an issue that needs attention at your residence. There is nothing anybody on this forum will be able to do for you unless you just want them to throw out possibilities and waste everyone's time. This issue has got to be taken care of in your neighborhood. |
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DrDrewSo that others may surf.
join:2009-01-28
SoCal
kudos:9
1 edit | reply to koma3504
said by koma3504:Meanwhile something like upstream signal reflections, hum modulation, or ground loops on his home wiring can cause upstream signal problems and T3s for him and no one else. It wouldn't even register on the CMTS since those are aggregate upstream readings from all the modems on the port. Could you explian this a a little more?? So that I might check for such. These sorts of things are rather rare, but not unheard of.
To measure them, you need the right meter and experience. Otherwise many of these problems are just fixed through swapping suspect parts.
Damaged cable, bad cable termination, and bad passive equipment in the home and system can cause signal reflections.
Hum modulation is caused by splitters and taps passing power. Most cable installed equipment has power blocking capacitors to stop this to a certain degree. Power can be put on the cable through hot chassis conditions, defective equipment, and hot/neutral swaps on some equipment such as TVs, computers modems, and other devices hooked to the cable system.
Ground loops occur when there are multiple paths to ground. Limiting grounding to one path usually eliminates this.
Phone techs and most service techs won't have a clue on what these things are. Most tech meters won't even pick these things up either. |
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