I keep getting "No Ranging Response received - T3 time-out" errors on my Arris SB6190. I've placed a brand new SB6190, as well as an older Motorola SB6141, and all have had the same issue. (Both Arris SB6190's were brand new out of the box). I'm using commercial grade Ubiquiti networking equipment, and have eliminated them as the problem, as the problem happens when DCHP directly to the modem. This issue has been happening consistently since I first moved in to my home (Feb 2018).
My downstream signal levels are good. SNR downstream is also good.
Upstream has always been an issue. I was observing peaks where the CMTS would crank my modems upstream output level beyond 52 (thus out of spec) and the modem would timeout.
This prompted me to remove all splitters between my modem and the Comcast Tap. The RG-6 cable going to the tap is directly connected to the grounding block from Comcast -- so it's directly connected to the proverbial 'pipe'. The ends are terminated with the best compression fittings in the industry and brand new.
Whenever the line comes under load (E.g. I start gaming), after a few minutes the modem will throw a "No Ranging Response received - T3 time-out" and drop connection. Looking at my logs, I always observe one or more of the upstream power-levels spiked higher than normal, telling me the CMTS at the other side of the pipe cranked my levels for some reason (presumably bad SNR in the up-stream connection).
Below is my signal readout (down levels are high because I'm directly connected to the 'Pipe' as stated previously.)
Channel Lock Status Modulation Channel ID Frequency Power SNR Corrected Uncorrectables 1 Locked 256QAM 27 627.00 MHz 4.20 dBmV 40.37 dB 5 45 2 Locked 256QAM 34 441.00 MHz 6.40 dBmV 40.37 dB 0 0 3 Locked 256QAM 35 447.00 MHz 6.10 dBmV 40.37 dB 0 0 4 Locked 256QAM 36 453.00 MHz 6.40 dBmV 40.37 dB 0 0 5 Locked 256QAM 37 459.00 MHz 6.40 dBmV 40.37 dB 0 0 6 Locked 256QAM 1 465.00 MHz 6.30 dBmV 40.37 dB 0 0 7 Locked 256QAM 2 471.00 MHz 6.10 dBmV 40.37 dB 0 0 8 Locked 256QAM 3 477.00 MHz 6.20 dBmV 40.37 dB 0 0 9 Locked 256QAM 4 483.00 MHz 6.50 dBmV 40.37 dB 0 0 10 Locked 256QAM 5 489.00 MHz 6.50 dBmV 40.37 dB 0 0 11 Locked 256QAM 6 495.00 MHz 6.50 dBmV 40.37 dB 0 0 12 Locked 256QAM 7 507.00 MHz 6.30 dBmV 40.37 dB 7 0 13 Locked 256QAM 8 513.00 MHz 5.90 dBmV 40.37 dB 0 0 14 Locked 256QAM 9 519.00 MHz 5.90 dBmV 40.37 dB 16 0 15 Locked 256QAM 10 525.00 MHz 6.00 dBmV 40.37 dB 0 0 16 Locked 256QAM 11 531.00 MHz 5.70 dBmV 38.98 dB 0 0 17 Locked 256QAM 12 537.00 MHz 5.60 dBmV 38.98 dB 0 0 18 Locked 256QAM 13 543.00 MHz 5.60 dBmV 40.37 dB 3 0 19 Locked 256QAM 14 549.00 MHz 5.70 dBmV 38.98 dB 0 0 20 Locked 256QAM 15 555.00 MHz 5.90 dBmV 38.98 dB 0 0 21 Locked 256QAM 16 561.00 MHz 6.30 dBmV 38.98 dB 0 0 22 Locked 256QAM 17 567.00 MHz 6.50 dBmV 40.37 dB 5 0 23 Locked 256QAM 18 573.00 MHz 6.90 dBmV 40.37 dB 11 0 24 Locked 256QAM 19 579.00 MHz 7.10 dBmV 40.95 dB 10 0 25 Locked 256QAM 20 585.00 MHz 7.00 dBmV 39.90 dB 10 0 26 Locked 256QAM 21 591.00 MHz 6.70 dBmV 39.90 dB 0 0 27 Locked 256QAM 22 597.00 MHz 6.10 dBmV 39.90 dB 0 0 28 Locked 256QAM 23 603.00 MHz 5.30 dBmV 39.50 dB 0 0 29 Locked 256QAM 24 609.00 MHz 4.90 dBmV 39.50 dB 0 0 30 Locked 256QAM 25 615.00 MHz 4.60 dBmV 38.90 dB 7 0 31 Locked 256QAM 26 621.00 MHz 4.10 dBmV 39.20 dB 0 0 32 Locked 256QAM 28 633.00 MHz 4.20 dBmV 39.20 dB 0 0 Upstream Bonded Channels Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power 1 Locked ATDMA 4 5120 kSym/s 16.60 MHz 35.50 dBmV 2 Locked ATDMA 3 5120 kSym/s 23.00 MHz 35.00 dBmV 3 Locked ATDMA 2 5120 kSym/s 29.40 MHz 35.50 dBmV 4 Locked ATDMA 1 5120 kSym/s 35.80 MHz 35.25 dBmV
How do I get the upstream line-levels and SNR inspected at the plant? An in-home tech cannot do that.
Solved! Go to Solution.
Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home.
I totally understand.
I feel like cutting out the middle man would be less timeconsuming in this instance. I, unforutnately, don't have hours to commit to being available away from work for a Tech to make their visits, especially considering they're going to charge a fee for the visit just to escalate to an engineer at the plant anyways.
Here is an example of what I am talking about. A random spike on Upstream - almost outside of spec. Channel 3 spiked 12.75 dBmV.
Modem is connected directly to Comcast's ground block at the houses demarc.
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power 1 Locked ATDMA 4 5120 kSym/s 16.60 MHz 39.50 dBmV 2 Locked ATDMA 3 5120 kSym/s 23.00 MHz 39.75 dBmV 3 Locked ATDMA 2 5120 kSym/s 29.40 MHz 48.25 dBmV 4 Locked ATDMA 1 5120 kSym/s 35.80 MHz 38.75 dBmV
Comcast Tech visited today.
After standing in my office and watching the modem reset itself as I explained the issues I've been having and my observations, they were unable to find an issue within my home, as expected. They were reading +10dB on their pipe, but we were seeing +7 to +8dB on my modem's downstream, with an SNR of over 39dB. My upstream power levels typically sit between 33dB to 40dB from a weeks worth of observations. At times they peak in the mid to high 40's, which is concerning, but not out of spec. Because of the signal drop between the pipe and my modem, the tech wanted to assume it was the cable ran between the DMARC and my modem. After educating the tech on the signal loss that a MoCA filter can cause in the ingress, and his supervisor confirming this, they replaced my MoCA filter/grounding block at the DMARC of the house, and ran a new line... Just in case.
Apparently, according to the tech (after spending 10+ minutes on the phone with his supervisor who told this to him), there were 7 signal issues within my neighborhood for the 'Signal team/Noise Patrol'. The exact words used by the tech were "It's a plant issue - it's not your house". This morning alone, there were 5 tech visits to my neighborhood including mine.
The most concerning thing the tech shared: a home a few houses down has a SNR near 0, and it's been an ongoing issue for over a month. I saw this home with a brand-new shielded RG6 between the ground-box and their house that's been there for about this same duration, unburried, so I can corroberate that this is probably true. It was burried only a week or so ago. This is very, very troubling to me, especially considering this issue is still ongoing for this customer, and hasn't been corrected.
Am I to expect a multi-month issue to continue at my home, as well?
Fun fact - since the tech has left, the issue has persisted (you can see the logs below). I see random losses of connection, yet the modem never indicates (via status lights) that it's lost connection. Other times, it fully loses sync and resets entirely.
https://i.imgur.com/LF3Ex7T.png <--- LOGs
https://i.imgur.com/F5YNXWI.png <--- Signal
Since the tech left (only changes: new line between House and Comcast - new MoCA filter):
Even with the intermittent connection interruptions, my upload speeds typically sat between 10-11Mbps when using standard speed tests.
Now it's struggling to get over 2-3Mbps upload.
Something is immensly wrong.
I just want to say thank you for continuing to update this post. I am seeing almost the same exact thing at my house. Gonna see if I can find an unterminated end outside.