Not applicable

<5Mbps speeds, MDD message timeouts, T3 timeouts

For the past two weeks I've been having extremely slow download speeds  (sometimes 5mbps and below, even on 60/5). Log is full of MDD and T3 timeouts.

Here are my signal stats...

Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables

1LockedQAM2569705000000 Hz4.8 dBmV37.1 dB37021700
2LockedQAM2566687000000 Hz4.9 dBmV37.8 dB42506811
3LockedQAM2567693000000 Hz5.1 dBmV37.5 dB38147771
4LockedQAM2568699000000 Hz4.4 dBmV37.1 dB39327041
5LockedQAM25610711000000 Hz4.9 dBmV36.3 dB387733442
6LockedQAM25612723000000 Hz4.6 dBmV36.5 dB41790671
7Not Lockedunknown14735000000 Hz2.9 dBmV0.0 dB363230089666679
8LockedQAM25615741000000 Hz3.8 dBmV26.4 dB130666377223475

 

Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power

1LockedATDMA715120 Ksym/sec30600000 Hz46.3 dBmV
2LockedTDMA692560 Ksym/sec19400000 Hz49.3 dBmV
3LockedATDMA705120 Ksym/sec24200000 Hz48.8 dBmV
4LockedATDMA722560 Ksym/sec37000000 Hz45.5 dBmV

 


And the event log...

 Sat Apr 22 15:35:07 2017   Warning (5)  MDD message timeout;CM-MAC=18:d6:c7:9a:79:f0;CMTS-MAC=00:01:5c:9c:b2:4e;CM-QOS=1.1;CM-VER=3.0; 
 Sat Apr 22 14:10:05 2017   Critical (3)  Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=18:d6:c7:9a:79:f0;CMTS-MAC=00:01:5c:9c:b2:4e;... 
 Sat Apr 22 14:10:03 2017   Warning (5)  MDD message timeout;CM-MAC=18:d6:c7:9a:79:f0;CMTS-MAC=00:01:5c:9c:b2:4e;CM-QOS=1.1;CM-VER=3.0; 
 Sat Apr 22 14:09:41 2017   Critical (3)  Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=18:d6:c7:9a:79:f0;CMTS-MAC=00:01:5c:9c:b2:4e;... 
 Sat Apr 22 14:09:27 2017   Warning (5)  MDD message timeout;CM-MAC=18:d6:c7:9a:79:f0;CMTS-MAC=00:01:5c:9c:b2:4e;CM-QOS=1.1;CM-VER=3.0; 
 Sat Apr 22 13:50:40 2017   Critical (3)  Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=18:d6:c7:9a:79:f0;CMTS-MAC=00:01:5c:9c:b2:4e;... 
 Sat Apr 22 13:50:23 2017   Warning (5)  MDD message timeout;CM-MAC=18:d6:c7:9a:79:f0;CMTS-MAC=00:01:5c:9c:b2:4e;CM-QOS=1.1;CM-VER=3.0; 
 Sat Apr 22 13:37:53 2017   Critical (3)  Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=18:d6:c7:9a:79:f0;CMTS-MAC=00:01:5c:9c:b2:4e;... 
 Sat Apr 22 13:26:21 2017   Warning (5)  MDD message timeout;CM-MAC=18:d6:c7:9a:79:f0;CMTS-MAC=00:01:5c:9c:b2:4e;CM-QOS=1.1;CM-VER=3.0; 


It seems channels 13, 14, 15 and 16  (when/if my modem bonds to those channels) all get millions of uncorrectable codewords within hours of powering up.

The modem is a TP-Link TC-7610. It replaced an Arris SB6121  yesterday, which had the same problems with the same channels, so I bought the TP-Link to see if that would solve the issue. Obviously it didn't.

Tried contacting Spectrum twice and they keep insisting my signal levels are on spec. :/

6 REPLIES 6
Expert

Re: <5Mbps speeds, MDD message timeouts, T3 timeouts

You have corroded or loose connections or open splitter ports and getting severe ingress from 4G LTE phones, cell sites and land mobile radio.

Everything must be shiny and a tad more than finger tight including the backsides of wall plates, there can't be any surge strips or ups F feedthru's in the line either.

 

Not applicable

Re: <5Mbps speeds, MDD message timeouts, T3 timeouts

The modem is the only device connected to the cable line. I tried different cables and even replaced the wall connector. There is RG59 cable that runs from my wall to the condominum's tap (about 10 feet run or so).

I'm guessing it's the rat nest that is the building's tap. Open F connectors that aren't closed off, wires hanging out, splices everywhere.  I have little faith that the techs will do anything to fix it. More times than I can count since I've moved here I've seen TWC (and recently Spectrum) techs working on the thing and leaving it in the sorry state that it is. What would it take to address it? Once again trying to get phone tech to address my speed issues is like trying to squeeze blood out of a stone.

Perhaps tomorrow when it's light out I can get a picture of the tap and post it here.

Expert

Re: <5Mbps speeds, MDD message timeouts, T3 timeouts

735 and 741 are the cell site transmit freq's used by Tmobile and AT&T, the other half of the -30 mHz 705/711 mHz bands that the handsets transmit on. Is there a cell site on the building, or one of the thimble shapedantenna on a pole outside?

It's probably the in building wiring, rg59 (the old copper braid stuff) is really awfull as the braid oxidises and that is a non conductive noise generator

You need a seperate, new line out to the street where there should be a pole monted tap off block

 

Not applicable

Re: <5Mbps speeds, MDD message timeouts, T3 timeouts

It's a pedestal tap from an underground line. Here's a picture I took...

http://i.imgur.com/jrtjXdj.jpg

That "ingress" tag is interesting. I've seen that orange tag for years but until now I've never read what it actually said.  It's disconcerting that techs have been at this pedestal many, many times (once in the past week at least) and never disconnected that cable.

There are two cell towers about 1/4 mile from here. I'm subscribed to T-Mobile myself, and I tried powering off my phone to see what it would do to my modem signal but nothing changed.

Expert

Re: <5Mbps speeds, MDD message timeouts, T3 timeouts

The first thing that someone needs to do is take an Egress measurement, then replace ALL THE F CONNECTORS to see if that reduces the Egress and raises s/n on the 4G channels. They are too stupid, lazy or want callbacks to that site. That is alao at the end of a line, so the upstream pedestalls need to be checked as well, it may be corroded/ loose hardline fittings...

 If you know any ham radio operators, they should be able to easily check for egress points which are also where ingress is getting in.

 I see a lot of old style >4 year old F connectors.

 

Expert

Re: <5Mbps speeds, MDD message timeouts, T3 timeouts

Get a photo of your and other grounding blocks, bet they're even worst

BTW, the FCC will cite them for egress if it's over a certain level, it also interferes with 4G LTE and public safety 700-800 radio systems and perhaps a comm tech can get involved and file a complaint with the fcc.