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CM1150V - Partial Service on Downstream Bonded Chan and High Codeword Count on Downstream OFDM Chan

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CM1150V - Partial Service on Downstream Bonded Chan and High Codeword Count on Downstream OFDM Chan

So I recently purchased and activated a CM1150V for use with Xfinity gigabit internet service and am getting intermittent connectivity.  The downstream LED is constantly flashing.  The downstream bonded channel is reporting partial service and the downstream OFDM channel has high codeword counts.  I have posted the event log, EMTA event log, and cable connection status below. 

 

Comcast has already been out and reterminated my supply line at the tap as it was bent 90 degrees at the connector.  At my box they added a MOCA filter and replaced a splitter and it's input cable.  And I replaced the barrel connector and pigtail at the modem.  None of this seemed to help.  Most of my downstream power levels were around the top of the range at +7 dBmV so I have added a 6 dB attenuation to bring them in mid range and it has stabilized considerably.  This has raised my upstream power levels beyond the Netgear stated range, but it seems like my problem is still on the downstream.  

 

At this point I can only think to replace the modem but am looking for any suggestions.  Thanks!

TimePriorityDescription
Tue Jul 21 18:30:59 2020Notice (6)CM-STATUS message sent. Event Type Code: 5; Chan ID: 28 30; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=28:80:88:d3:8a:b8;CMTS-MAC=00:56:2b:76:d1:ce;CM-QOS=1.1;CM-VER=3.1;
Tue Jul 21 18:30:58 2020Notice (6)CM-STATUS message sent. Event Type Code: 20; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=28:80:88:d3:8a:b8;CMTS-MAC=00:56:2b:76:d1:ce;CM-QOS=1.1;CM-VER=3.1;
Tue Jul 21 18:30:58 2020Notice (6)CM-STATUS message sent. Event Type Code: 2; Chan ID: 29; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=28:80:88:d3:8a:b8;CMTS-MAC=00:56:2b:76:d1:ce;CM-QOS=1.1;CM-VER=3.1;
Tue Jul 21 18:30:55 2020Warning (5)MDD message timeout;CM-MAC=28:80:88:d3:8a:b8;CMTS-MAC=00:56:2b:76:d1:ce;CM-QOS=1.1;CM-VER=3.1;

 

TimeTextEndpointName
2020-07-21 18:04:38DHCP ERROR:OFFER;REQUESTING;Option 122.3 contains invalid FQDN0.0.0.0

 

Downstream Bonded Channels (Partial Service)
ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
1LockedQAM25637651000000 Hz-0.7 dBmV40.6 dB00
2LockedQAM2569471000000 Hz-1 dBmV40.7 dB00
3LockedQAM25610477000000 Hz0 dBmV41 dB00
4LockedQAM25611483000000 Hz-0.1 dBmV40.8 dB00
5LockedQAM25612489000000 Hz0 dBmV40.6 dB00
6LockedQAM25613495000000 Hz-0.5 dBmV40.3 dB40
7LockedQAM25614507000000 Hz-1.3 dBmV40.5 dB00
8LockedQAM25615513000000 Hz-1.9 dBmV39.3 dB00
9LockedQAM25616519000000 Hz-1.8 dBmV39.6 dB00
10LockedQAM25617525000000 Hz-1.8 dBmV35.4 dB00
11LockedQAM25618531000000 Hz-1.3 dBmV30.3 dB12130
12LockedQAM25619537000000 Hz-0.7 dBmV32.1 dB50
13LockedQAM25620543000000 Hz-0.7 dBmV33.8 dB00
14LockedQAM25621549000000 Hz-1.3 dBmV37.2 dB00
15LockedQAM25622555000000 Hz-1 dBmV34.4 dB00
16LockedQAM25623561000000 Hz-1.8 dBmV33 dB00
17LockedQAM25624567000000 Hz-1.4 dBmV28.9 dB9185451
18LockedQAM25625573000000 Hz-0.8 dBmV35.9 dB00
19LockedQAM25626579000000 Hz-1.1 dBmV38.6 dB00
20LockedQAM25627585000000 Hz-0.6 dBmV40.4 dB00
21Not LockedUnknown28591000000 Hz0.0 dBmV0.0 dB00
22Not LockedUnknown29597000000 Hz0.0 dBmV0.0 dB00
23LockedQAM25630603000000 Hz-0.8 dBmV26.9 dB27128017104
24LockedQAM25631609000000 Hz-0.8 dBmV36.2 dB00
25LockedQAM25632615000000 Hz-0.9 dBmV40.5 dB00
26LockedQAM25633621000000 Hz-0.6 dBmV40.3 dB00
27LockedQAM25634627000000 Hz-0.3 dBmV40.2 dB00
28LockedQAM25635639000000 Hz-0.9 dBmV40.5 dB00
29LockedQAM25636645000000 Hz-0.1 dBmV40.6 dB00
30LockedQAM25638657000000 Hz-0.7 dBmV40.6 dB00
31LockedQAM25639663000000 Hz-0.3 dBmV40.6 dB00
32LockedQAM25640669000000 Hz-0.8 dBmV40.5 dB00
 
Upstream Bonded Channels
ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA15120 Ksym/sec35800000 Hz54.5 dBmV
2LockedATDMA25120 Ksym/sec29400000 Hz55.5 dBmV
3LockedATDMA35120 Ksym/sec23000000 Hz58.8 dBmV
4LockedATDMA45120 Ksym/sec16600000 Hz54.5 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
 
Downstream OFDM Channels
ChannelLock
Status
Modulation /
Profile ID
Channel
ID
FrequencyPowerSNR /
MER
Active Subcarrier
Number Range
Unerrored
Codewords
Correctable
Codewords
Uncorrectable
Codewords
1Locked0 ,1159690000000 Hz-0.2 dBmV303.6 dB1246 ~ 28492005547106501995931
2Not Locked000 Hz0 dBmV0.0 dB0 ~ 4095000
 
Upstream OFDMA Channels
ChannelLock StatusModulation / Profile IDChannel IDFrequencyPower
1Not Locked000 Hz0 dBmV
2Not Locked000 Hz0 dBmV
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Diamond Problem Solver

Re: CM1150V - Partial Service on Downstream Bonded Chan and High Codeword Count on Downstream OFDM C

Get rid of the attenuators, downstream at 7db isn’t close to the top of the range, it’s hurting you more than helping. You also have several channels below the acceptable level of 35 and some channels with none at all

What’s a pigtail?

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Regular Visitor

Re: CM1150V - Partial Service on Downstream Bonded Chan and High Codeword Count on Downstream OFDM C

Yeah I was going off the downstream specs on Netgear's site which says -7 to +7.  I've pulled the attenuator and am now getting the below.  Still seeing the downstream OFDM channel unlock.  I was missing the same downstream bonded channels on my XB6 and don't recall it having downstream OFDM lock at all.  By pigtail I was referring to the cable from the wall port to the modem.  

 

Downstream Bonded Channels (Partial Service)
ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
1LockedQAM25637651000000 Hz5.7 dBmV40.6 dB00
2LockedQAM2569471000000 Hz6 dBmV36.4 dB00
3LockedQAM25610477000000 Hz6.5 dBmV41.1 dB00
4LockedQAM25611483000000 Hz5.9 dBmV40.9 dB00
5LockedQAM25612489000000 Hz5.9 dBmV40.7 dB00
6LockedQAM25613495000000 Hz5.7 dBmV40.5 dB00
7LockedQAM25614507000000 Hz5.9 dBmV40.8 dB00
8LockedQAM25615513000000 Hz5.2 dBmV39.3 dB00
9LockedQAM25616519000000 Hz4.9 dBmV39.6 dB00
10LockedQAM25617525000000 Hz4.4 dBmV36.7 dB00
11LockedQAM25618531000000 Hz4.6 dBmV31.4 dB130
12LockedQAM25619537000000 Hz5.3 dBmV31 dB00
13LockedQAM25620543000000 Hz5.9 dBmV33.3 dB00
14LockedQAM25621549000000 Hz5.9 dBmV37.1 dB00
15LockedQAM25622555000000 Hz6.1 dBmV34.6 dB00
16LockedQAM25623561000000 Hz4.9 dBmV32.6 dB00
17LockedQAM25624567000000 Hz4.9 dBmV29.9 dB122930
18LockedQAM25625573000000 Hz5.2 dBmV34.5 dB00
19LockedQAM25626579000000 Hz5 dBmV38.7 dB00
20LockedQAM25627585000000 Hz5.9 dBmV40.6 dB00
21Not LockedUnknown28591000000 Hz0.0 dBmV0.0 dB00
22Not LockedUnknown29597000000 Hz0.0 dBmV0.0 dB00
23LockedQAM25630603000000 Hz6 dBmV27.1 dB4891425079
24LockedQAM25631609000000 Hz5.6 dBmV34.5 dB00
25LockedQAM25632615000000 Hz5.2 dBmV40.5 dB00
26LockedQAM25633621000000 Hz5.5 dBmV40.3 dB00
27LockedQAM25634627000000 Hz6.2 dBmV40.1 dB00
28LockedQAM25635639000000 Hz6.2 dBmV40.7 dB00
29LockedQAM25636645000000 Hz6.8 dBmV40.8 dB00
30LockedQAM25638657000000 Hz5.4 dBmV40.6 dB00
31LockedQAM25639663000000 Hz5.7 dBmV40.6 dB00
32LockedQAM25640669000000 Hz5.6 dBmV40.6 dB00
 
Upstream Bonded Channels
ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA15120 Ksym/sec35800000 Hz49 dBmV
2LockedATDMA25120 Ksym/sec29400000 Hz49.5 dBmV
3LockedATDMA35120 Ksym/sec23000000 Hz52.5 dBmV
4LockedATDMA45120 Ksym/sec16600000 Hz48.5 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
 
Downstream OFDM Channels
ChannelLock
Status
Modulation /
Profile ID
Channel
ID
FrequencyPowerSNR /
MER
Active Subcarrier
Number Range
Unerrored
Codewords
Correctable
Codewords
Uncorrectable
Codewords
1Locked0159690000000 Hz6.3 dBmV303.6 dB1246 ~ 2849236613143236798
2Not Locked000 Hz0 dBmV0.0 dB0 ~ 4095000
 
Upstream OFDMA Channels
ChannelLock StatusModulation / Profile IDChannel IDFrequencyPower
1Not Locked000 Hz0 dBmV
2Not Locked000 Hz0 dBmV
Highlighted
Diamond Problem Solver

Re: CM1150V - Partial Service on Downstream Bonded Chan and High Codeword Count on Downstream OFDM C

Your downstream OFDM is locked(there’s only 1). Keep going backwards and test your levels at the ground block for comparison

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Re: CM1150V - Partial Service on Downstream Bonded Chan and High Codeword Count on Downstream OFDM C

Success!  So took your advice and brought the modem out to the ground block and couldn't even get a connection.  Got to thinking that my box is right up on my main electrical feed and the HVAC feed.  The Comcast guy who came out today did note that he was seeing excessive signal level fluctuation but said it shouldn't be hurting me.  Luckily I live in a townhome, so decided to sneak and tap my neighbor's box which is free and clear.  Rock solid now.  In fact, I know I clocked speeds up to 400 mbps when I first had the service installed.  Once the COVID-19 lockdown kicked in I decided to do a little speed test out of curiosity as I expected heavy loads in the neighborhood and couldn't get much above 30 mbps.  I chalked it up to stress on the network, but I did check my levels and noticed those missing downstream bonded channels unlocked.  Not knowing any better I just figured it was normal.  Looks like I'll be talking to Comcast in the morning about relocating my box.  Thanks for all your help!

 

For future concerned readers, make sure your bonded downstream channels have at least a 35 dB SNR as mentioned by @CCAndrew .  Also, not sure if this is just for the CM1150V but my downsream OFDM channel SNR was reading around 303.5 dB even with a wide range of power level which I thought was strange.  That must just be a glitch in reading an unstable signal I guess.  But good rule of thumb for installations, keep your RF and power cables separated!

 

Downstream Bonded Channels
ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
1LockedQAM25621549000000 Hz14 dBmV40.8 dB00
2LockedQAM2569471000000 Hz14.9 dBmV41.2 dB00
3LockedQAM25610477000000 Hz15.1 dBmV41.2 dB00
4LockedQAM25611483000000 Hz15 dBmV41.1 dB00
5LockedQAM25612489000000 Hz14.8 dBmV41 dB00
6LockedQAM25613495000000 Hz14.7 dBmV41 dB00
7LockedQAM25614507000000 Hz14.4 dBmV40.9 dB00
8LockedQAM25615513000000 Hz14.3 dBmV40.8 dB00
9LockedQAM25616519000000 Hz14 dBmV40.8 dB00
10LockedQAM25617525000000 Hz14.1 dBmV40.9 dB00
11LockedQAM25618531000000 Hz14 dBmV40.8 dB00
12LockedQAM25619537000000 Hz14.2 dBmV40.9 dB00
13LockedQAM25620543000000 Hz14.1 dBmV40.9 dB00
14LockedQAM25622555000000 Hz14.1 dBmV40.7 dB00
15LockedQAM25623561000000 Hz14 dBmV40.6 dB00
16LockedQAM25624567000000 Hz14 dBmV40.8 dB00
17LockedQAM25625573000000 Hz14.1 dBmV40.8 dB00
18LockedQAM25626579000000 Hz13.9 dBmV40.7 dB00
19LockedQAM25627585000000 Hz13.9 dBmV40.7 dB00
20LockedQAM25628591000000 Hz14.1 dBmV40.9 dB00
21LockedQAM25629597000000 Hz14.2 dBmV40.9 dB00
22LockedQAM25630603000000 Hz14.1 dBmV40.8 dB00
23LockedQAM25631609000000 Hz14 dBmV40.7 dB00
24LockedQAM25632615000000 Hz13.9 dBmV40.6 dB00
25LockedQAM25633621000000 Hz13.9 dBmV40.6 dB00
26LockedQAM25634627000000 Hz14 dBmV40.5 dB00
27LockedQAM25635639000000 Hz14.1 dBmV40.6 dB00
28LockedQAM25636645000000 Hz14.3 dBmV40.6 dB00
29LockedQAM25637651000000 Hz14.2 dBmV40.6 dB00
30LockedQAM25638657000000 Hz14.3 dBmV40.6 dB00
31LockedQAM25639663000000 Hz14.3 dBmV40.5 dB00
32LockedQAM25640669000000 Hz14.2 dBmV40.5 dB00
 
Upstream Bonded Channels
ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA15120 Ksym/sec35800000 Hz39.3 dBmV
2LockedATDMA25120 Ksym/sec29400000 Hz39.8 dBmV
3LockedATDMA35120 Ksym/sec23000000 Hz39.8 dBmV
4LockedATDMA45120 Ksym/sec16600000 Hz39.8 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
 
Downstream OFDM Channels
ChannelLock
Status
Modulation /
Profile ID
Channel
ID
FrequencyPowerSNR /
MER
Active Subcarrier
Number Range
Unerrored
Codewords
Correctable
Codewords
Uncorrectable
Codewords
1Locked0 ,1159690000000 Hz14.7 dBmV40.7 dB1246 ~ 28495004548129254170
2Not Locked000 Hz0 dBmV0.0 dB0 ~ 4095000
 
Upstream OFDMA Channels
ChannelLock StatusModulation / Profile IDChannel IDFrequencyPower
1Not Locked000 Hz0 dBmV
2Not Locked000 Hz0 dBmV
Highlighted
Expert

Re: CM1150V - Partial Service on Downstream Bonded Chan and High Codeword Count on Downstream OFDM C

FWIW, the downstream power is very high now. If everything is ok, don't sweat it. If you want to knock it down some you could use a forward path only attenuator;

 

https://www.amazon.com/line-Signal-Forward-Attenuator-FPA6-54/dp/B07882H96R

 

It does not affect the upstream power. Also, it is a known issue that some makes and models of modems measuring mechanisms do not read the OFDM channel's power, SNR, and the bit errors correctly. Good luck !

 

 



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