pbarrow
Premium
join:2003-09-16
Montgomery, AL
| reply to DxViperMan
Re: [HSI] modem signal discrepancies
said by DxViperMan  :hmm, your signal levels changed that much in one night? as a tech, the 1sy thing i would check would be for 1 of 2 things. 1. did you make ANY changes to any cable wiring in the house or outside in the box, like maybe adding a splitter? changing the way it was setup the day before? 2. I would look outside in the box or around the house to see if your neighbor came over in the middle of the night and put a splitter on your line to get cable at his house by stealing it from you. cable signals don't just change without a reason. there are no moving parts so something had to change to make levels change much more than a few db. it is possible that is could be a mainline issue, but unlikely or everyone in your area would have the same issue and with those levels on the downstream, some modems would never get a connection at all or at best, intermittent There are ongoing problems for months in my area.
I had a Corporate Escaltion in May due to imtermittent noise problems that was fixed for a while.
Then again the 1st of 2 weeks ago and again yesterday concerning the latest 2.
The current problem is still not fixed.
Here are 2 emails fromt he local Plant Manager.
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Sept 5, 2007
Hello Mr. Barrow,
We found some trouble in the plant in your neighborhood. There was some ingress getting into the node and we cleared it at about 5pm last evening. This would cause problems with SNR. We have been keeping an eye on it and it has remained clean so far. We are going to sweep and balance the node later today, so you may experience a few very brief interruptions while that is being done, otherwise everything should be working normally at this point.
Ed Keeley
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Sept 14, 2007
We can see on the spectrum analyzer that there is some impulse noise on the line. We have dispatched a plant tech to chase it down.
ed |
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DxViperMan
Computer nut
Premium
join:2003-08-08
Klamath Falls, OR
| reply to pbarrow
hmm, your signal levels changed that much in one night? as a tech, the 1sy thing i would check would be for 1 of 2 things.
1. did you make ANY changes to any cable wiring in the house or outside in the box, like maybe adding a splitter? changing the way it was setup the day before?
2. I would look outside in the box or around the house to see if your neighbor came over in the middle of the night and put a splitter on your line to get cable at his house by stealing it from you.
cable signals don't just change without a reason. there are no moving parts so something had to change to make levels change much more than a few db. it is possible that is could be a mainline issue, but unlikely or everyone in your area would have the same issue and with those levels on the downstream, some modems would never get a connection at all or at best, intermittent |
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defiant
Garbage in, garbage out
MVM
join:2000-09-04
Monroe, MI
| reply to pbarrow
The diagnostic tools we use pull info directly from the modem and/or the CMTS; they can be depended on.
Just an FYI - you're close to, if not in direct violation of posting personal message content
»Site FAQ »Posting IM content is not allowed! |
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pbarrow
Premium
join:2003-09-16
Montgomery, AL
| Odd problem.
Bufftech has beem keeping me posted on my signal levels - especially Upstream SNR. Up until today the info he's been sending me has be accurate.
He left me a message today that my signals were
Modem Rx Power -13.3 dBmV (range-12-12) Modem Rx SNR 35.7 dB (>=33) Modem Tx
Power 54.3 dBmV (range35-50) CMTS Rx SNR 29.3 dB (>22)
The odd change occurred last night close to midnight.
(I don't know if it could be related but about approx 6:00pm
last night I got
SYNC: Hardware didn't detect SYNC msg for 600ms - Disable Upstream and trying to lock on DS
in my modem log. So something did happen last night)
But my modem page is saying they are:
Frequency 603000000 Hz
Signal to Noise Ratio 36 dB
QAM QAM256
Network Access Control Object ON
Power Level 6 dBmV
Upstream Value
Channel ID 3
Frequency 34608000 Hz
Ranging Service ID 250
Symbol Rate 2.560 Msym/s
Power Level 40 dBmV
So I called Tech support and asked the CSR what he was seeing and he was seeing the same levels as Bufftech was.
I told him want I was seeing and asked him why the discrepancy? He said their Tool might not be working correctly that sometimes it didn't and that my modem page should be correct.
To further test I disconnected my SB5120 and hooked up my old SB3100 - no internet access of course since it's not provisioned - but I was able to check the signal levels on it and they were about the same:
35 SNR 6db DS pwr and 39db US pwr
So I put my SB5120 back and still the same levels it showed before.
I guess another instance we can't always depend on Charter's own tools for diagnosis  |
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