Lingering issues after line tech visits



I've had the line techs come out twice now to my home in Dallas to try and salvage the hot mess that is my connection... Originally I had 20/24 channels below -15dBmV, but they adjusted things and it's a little better now. A few lingering issues though:


1) Even after line maintenance, I have one channel that has a ton of uncorrectables, and I'm not sure why. This channel is also repeatedly losing lock. It's at 753MHz which is LTE spectrum if I remember correctly.

2) Tons of correctables, probably because the signal out here is bonkers.

3) TDMA channel is running at 38dBmV, not sure if it should be doing that? Seems a little low.

4) Lots of messages about T3 timeouts ever since I rebooted the modem this morning. I figure this may be related to item 3.


Can anyone provide some insight as to what I should do? If the line techs have been out here twice and signed off on the job, I'm kind of at a loss for how to make things better... If I need to keep complaining, I'd also rather complain effectively.


Thanks for taking a look.


Downstream Bonded Channels
ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
1LockedQAM25624813000000 Hz0.4 dBmV36.1 dB16362240
2LockedQAM2569723000000 Hz4.9 dBmV38.7 dB2828780
3LockedQAM25610729000000 Hz2.8 dBmV32.5 dB13900950
4LockedQAM25611735000000 Hz6.3 dBmV36.4 dB1672470
5LockedQAM25612741000000 Hz1.8 dBmV36.8 dB15612290
6LockedQAM25613747000000 Hz6.1 dBmV36.3 dB3877210
7LockedQAM25614753000000 Hz1.5 dBmV31.1 dB90951626360633
8LockedQAM25615759000000 Hz4.4 dBmV38.1 dB3495290
9LockedQAM25616765000000 Hz3.2 dBmV37.2 dB8484010
10LockedQAM25617771000000 Hz0.9 dBmV36.3 dB17263000
11LockedQAM25618777000000 Hz3.3 dBmV37.9 dB4853790
12LockedQAM25619783000000 Hz0.0 dBmV35.8 dB31346070
13LockedQAM25620789000000 Hz2.5 dBmV37.6 dB5253360
14LockedQAM25621795000000 Hz-1.6 dBmV34.8 dB66244650
15LockedQAM25622801000000 Hz2.2 dBmV37.5 dB5041200
16LockedQAM25623807000000 Hz-2.9 dBmV33.9 dB112238400
17LockedQAM25625819000000 Hz-3.8 dBmV33.9 dB15510
18LockedQAM25626825000000 Hz-4.4 dBmV33.0 dB23760
19LockedQAM25627831000000 Hz-2.5 dBmV34.5 dB10680
20LockedQAM25628837000000 Hz-5.3 dBmV33.0 dB33340
21LockedQAM25629843000000 Hz-1.9 dBmV35.6 dB3970
22LockedQAM25630849000000 Hz-6.8 dBmV31.6 dB68890
23LockedQAM25631855000000 Hz-3.2 dBmV34.8 dB3690
24LockedQAM25632861000000 Hz-7.3 dBmV30.5 dB89340
Upstream Bonded Channels
ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA25120 Ksym/sec24200000 Hz40.3 dBmV
2LockedTDMA12560 Ksym/sec19400000 Hz38.0 dBmV
3LockedATDMA35120 Ksym/sec30600000 Hz40.5 dBmV
4LockedATDMA45120 Ksym/sec37000000 Hz42.0 dBmV
5Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
6Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
7Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
8Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
2018-06-13, 21:08:58Warning (5)MDD message timeout;CM-MAC=10:da:43:50:84:39;CMTS-MAC=00:01:5c:a1:e4:61;CM-QOS=1.1;CM-VER=3.0;
2018-06-13, 20:29:37Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:da:43:50:84:39;CMTS-MAC=00:01:5c:a1:e4:61;CM-QOS=1.1;CM-VER=3.0;
2018-06-13, 20:28:50Warning (5)MDD message timeout;CM-MAC=10:da:43:50:84:39;CMTS-MAC=00:01:5c:a1:e4:61;CM-QOS=1.1;CM-VER=3.0;
2018-06-13, 18:48:47Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:da:43:50:84:39;CMTS-MAC=00:01:5c:a1:e4:61;CM-QOS=1.1;CM-VER=3.0;
2018-06-13, 18:48:45Warning (5)MDD message timeout;CM-MAC=10:da:43:50:84:39;CMTS-MAC=00:01:5c:a1:e4:61;CM-QOS=1.1;CM-VER=3.0;
2018-06-13, 17:02:37Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:da:43:50:84:39;CMTS-MAC=00:01:5c:a1:e4:61;CM-QOS=1.1;CM-VER=3.0;
2018-06-13, 16:59:01Warning (5)MDD message timeout;CM-MAC=10:da:43:50:84:39;CMTS-MAC=00:01:5c:a1:e4:61;CM-QOS=1.1;CM-VER=3.0;
2018-06-13, 15:14:00Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:da:43:50:84:39;CMTS-MAC=00:01:5c:a1:e4:61;CM-QOS=1.1;CM-VER=3.0;
2018-06-13, 15:07:44Warning (5)MDD message timeout;CM-MAC=10:da:43:50:84:39;CMTS-MAC=00:01:5c:a1:e4:61;CM-QOS=1.1;CM-VER=3.0;
2018-06-13, 10:48:53Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:da:43:50:84:39;CMTS-MAC=00:01:5c:a1:e4:61;CM-QOS=1.1;CM-VER=3.0;
2018-06-13, 10:48:21Warning (5)MDD message timeout;CM-MAC=10:da:43:50:84:39;CMTS-MAC=00:01:5c:a1:e4:61;CM-QOS=1.1;CM-VER=3.0;
2018-06-13, 09:57:16Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:da:43:50:84:39;CMTS-MAC=00:01:5c:a1:e4:61;CM-QOS=1.1;CM-VER=3.0;
2018-06-13, 09:57:11Warning (5)MDD message timeout;CM-MAC=10:da:43:50:84:39;CMTS-MAC=00:01:5c:a1:e4:61;CM-QOS=1.1;CM-VER=3.0;
2018-06-13, 06:46:43Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:da:43:50:84:39;CMTS-MAC=00:01:5c:a1:e4:61;CM-QOS=1.1;CM-VER=3.0;
2018-06-13, 06:45:08Warning (5)MDD message timeout;CM-MAC=10:da:43:50:84:39;CMTS-MAC=00:01:5c:a1:e4:61;CM-QOS=1.1;CM-VER=3.0;


EDIT-- Other useful info:

  • Dallas, TX 75243
  • Condo complex with 8 units, there's a mighty 10x splitter looking thing in the cable closet on the end of the building, and I'm told that signal from other buildings is impacting the signal at my building.
  • Only service used is Internet, 100mbps down, 10ish mbps up.
  • Netgear CM600 modem.
  • Seeing inconsistent latency for traffic passing through tge0-0-9.dllxtx5001h.texas.rr.com, nominal around 20ms with occasional spikes to >500ms. I am given to understand that there is some network congestion around here.

Please let me know if more information is required.


Re: Lingering issues after line tech visits

That cm600 may have a Puma chipset... forget exactly. But do recall reports of people not being too happy with it. The general recommendation was to go with the 500 or 700 from that line... stronger Broadcome chips if I remember right. Could be contributing to the lag spikes.

As for the signal wonkiness, not much you can do yours beyond inspecting/repair/replace/refit/rerunning your cabling kind of thing. In most scenarios, their responsibility generally kinda sorta ends at the point of demarcation, ie: the distribution amp--unless you have one of their modems and/or there is some sort of maintenance agreement in place that states otherwise.

Re: Lingering issues after line tech visits

Thanks RAIST5150, I appreciate the reply. For reference, I bought the CM600 specifically because it does not have a puma chipset. The 500 only supports 16x downstream channels, and the 700 uses a puma. Regarding lag spikes, a quick pingplotter exam showed that I rarely had any trouble up to the identified point in the network, which is well beyond my home connection; I don't think my modem is contributing to these lag spikes.


I'm hoping for some insight into why my signal behaves the way it does. I think it will be easier to make a case for correction to whoever is responsible for the lines if I understand the problem and can guide them to it immediately. I also fear that any issues I see may be negatively impacting other members of my community, and perhaps identification of my own issues can lead to improvements community-wide. I can worry about who's obliged to fix what once I understand the problem more.


Re: Lingering issues after line tech visits

It gets tricky in apartments and condos. They will pre-wire rooms with outlets... and may not terminate any of them. Basically, any outlet without a device on them potentially becomes a point of ingress from all kinds of devices. That could be in your unit or any of your neighbors, since you likely all share at least one big drop per building. And they rarely if ever will dig deeply through your living spaces looking for all of the odd little things that can trip things up, which can get quite frustrating... but they have some specific reasons for it that are pretty standard in the service industry. It is why their has to be someone on site for the visits actually... even if they aren't planning to do anything in the house... It is still private property, and both you and they need certain protections and assurances for the visit.

The coax cable can become compromised in weird ways. Too sharp of a bend (anything tighter than a bend around a 2 liter soda bottle may be pushing the limits), furniture and such crimping the cord... loose connections... rodents chewing on a line or foul weather stresses connectors/cables outside. Resistance must remain 75 ohms between center conductor and shielding across the entire run or you may get weird fluctuations/reflections in the signals.

All manner of weird things can cause a wide variance in signal strength from channel to channel. Ideally you want to see them fairly tight together without a whole lot of variance between each one as you step to each adjacent channel. And if they can't isolate the interference to occurring upstream from the drop, they will point to your local wiring/devices. And then you run into that weirdness factor with a dozen tenants sharing a drop across cables/devices they technically may not be responsible for maintaining.

Can be a real PITA sometimes... but it is just how they sorta have to operate in some markets. They go knocking around in the building and something goes wrong, it can open a big ol' can of worms.

Can be a tricky thing to track down on your own if you aren't familiar with these things. May be worth pulling in a tech savvy friend if you need help. Being able to verify there aren't issues internally on your premises goes a long way towards speeding the process... sometimes.

I am fortunate that I can easily do a fresh RG6 directly from the modem to their entry point in the utility closet. So whenever a tech points to my cable, it is an easy thing to test. I can just run a fresh line or replace the connectors if I need to. Last time we had this debate, we ruled out my specific CPE immediately and went to the outside... come to find out it was my neighbors tap that was bad. He went ahead and addressed the outside connection issue, but I had to go to Jo next door and make sure HER tv cables and all were tight and all that mess. Come to find out, their were three connected but unterminated jacks in her unit. Once we got her cleaned up, things improved dramatically for all of us in that building.

Re: Lingering issues after line tech visits

The wildly fluctuating power levels is a dead giveaway that you have some serious coax issues that is allowing ingress/egress that is the cause of 99% of your problems. Being an apartment/condo it could be a PITA for the tech to correctly diagnose and/or fix the issue. Sometimes apartment owners don't want to pay to have the wiring updated in the building as needed.