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Optimus2357
Premium
join:2010-11-21
West Warwick, RI
kudos:3

[RI] Change in Modem signal.

First my equipment.

Modem:SB6180
SB6180-3.5.8.4-GA-00-507-NOSH

Setup: Apartment drop (PCTDRS11L) > 3 Way balanced Splitter (SV-3G) > 3' to MTA + 15' Modem + 20' to Cable box.

Going back a month or two, I have seen a steady decline in downstream power level, where it started at -1 to +1 bonding over 8 channels downstream, and 3 to 4 channels upstream (this seems to change). A Cox Technician came out a couple months ago and mentioned he suspected some moisture damage on my drop where it comes into my apartment, and over the bathroom vent fan/light. I personally found this somewhat hard to believe, since the drop looks pretty beefy and designed to be outside. So as I saw my downstream power drop over the last couple months, I thought it was related to that.

More recently, I started seeing my upstream levels become more erratic. Most importantly, on March 1st, I lost service all together. At 2AM or so, my cable, telephone and internet all went out for 30-45min. What is interesting, when it came back, my downstream level was back to -1 to +1 and my Downstream SNR was 40-41. This leads me to believe that what ever was causing the signal problem was related to the outage, and not moisture damage to my drop. I noticed the next morning my signal levels were back down to -5 to -8. My service is not effected as of now, but if this trend of decreasing signal level continues, I fear it will.

1 Locked QAM256 1 837000000 Hz -5.0 dBmV 39.9 dB 0 0
2 Locked QAM256 2 843000000 Hz -5.4 dBmV 39.8 dB 0 0
3 Locked QAM256 3 849000000 Hz -6.0 dBmV 38.9 dB 0 0
4 Locked QAM256 4 855000000 Hz -6.2 dBmV 39.0 dB 0 0
5 Locked QAM256 9 867000000 Hz -6.9 dBmV 38.7 dB 0 0
6 Locked QAM256 10 873000000 Hz -7.5 dBmV 38.6 dB 0 0
7 Locked QAM256 11 879000000 Hz -7.4 dBmV 38.2 dB 0 0
8 Locked QAM256 12 885000000 Hz -7.7 dBmV 38.2 dB 1 0

1 Locked ATDMA 3 5120 Ksym/sec 32000000 Hz 41.7 dBmV
2 Locked ATDMA 2 2560 Ksym/sec 37000000 Hz 41.7 dBmV
3 Locked ATDMA 4 5120 Ksym/sec 25400000 Hz 41.7 dBmV
4 Not Locked Unknown 4 0 Ksym/sec 0 Hz 0.0 dBmV

I welcome anyone's input, specially a Cox engineer. MAC address available via PM.


Optimus2357
Premium
join:2010-11-21
West Warwick, RI
kudos:3
Ok, maybe I was a bit too long winded. I will simplify it; signal level has been dropping for a while. Recently after outage it went up, then back down. What would cause that, and when should the signal levels become a concern? Help?


Ender3rd

join:2001-07-15
Connecticut
reply to Optimus2357

Mmmmm... tasty!
Erratic signal levels and declining SNR do suggest that something is not quite right between you and Cox. As you said, it could be moisture or damage to the drop. In my area, the squirrels love munching on RG-6 cable like it's candy. The attached picture is from the drop at my place that was recently replaced. Hope the new run is less tasty! I would keep an eye on the two error count columns, which look very clean in the columns you pasted. If you suddenly see your error counts climbing that's an indication that the connection is struggling. Make sure you take a few screenshots of the signal levels, SNR, and error counts when things are running well for a baseline. If things deteriorate, take a few more screenshots to show the service tech when he arrives. As a side note, I'd love to have the SNR you are seeing.
--
Politicians are the only people in the world who create problems and then campaign against them. (Charlie Reese)


Optimus2357
Premium
join:2010-11-21
West Warwick, RI
kudos:3
I think my question is why would signal levels go up after a outage? If the drop was damaged, and that was causing the problem, the signal levels wouldn't go UP after a area wide problem and then go back down again. Also, when I use the word "drop" I don't mean it is outside,this is a large modern apartment complex, they run the wiring in cages in the highways. I can fallow my line from my apartment all the way to the maintenance closet. And in thinking back, the possible moisture damage was to explain a issue with the 4th channel upstream having issues. I think they have since shut it down, so I doubt it had anything to do with me.

See, I don't mind paying a Electrician to wall fish a new drop into my apartment, I would just rather explore other possibilities first. Last, there is no symptom to track, my internet isn't slow or bad. I just don't see why my power level has decreased and is -8 of a 3 way splitter direct of the drop. Doesn't that seem low to anyone? It seems like there is something in that maintenance closet that needs to be adjusted if you ask me.


Optimus2357
Premium
join:2010-11-21
West Warwick, RI
kudos:3
reply to Optimus2357
Called and made a appointment to take signal readings at tap and to have a look in general. Could Cox tech reply with what I should reasonably expect coming in at D-mark? Is +4 asking too much? Not sure how the signal is divided at the maintenance closet.