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Constant Disonnects

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Constant Disonnects

I have been experincing constant disconnects which seem to be getting more frequent and annoying. I am using a Netgear CM500 which is fairly new but experinced the same disconnects with my previous motorola surfboard modem. FInally had a tech come out today who said he dialed down the frequency level a little as it was high and should be fine. Disocnnects are still occuring several hours after and more frequent. A few weeks ago i disconnected the splitter and runnig the line straight to the modem but same issue. Also about a year ago i had comcast run a new line after they determined the line was not good.

 

I noticed in the modems error log the following throughout the day:

 

No Ranging Response received - T3 time-out

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received

Unicast Ranging Received Abort Response - Re-initializing

 

These are the frequency stats on the modem. I appreciate any advice.

 

Startup Procedure
ProcedureStatusComment
Acquire Downstream Channel579000000 HzLocked
Connectivity StateOKOperational
Boot StateOKOperational
SecurityEnabledBPI+
IP Provisioning ModeHonor MDDhonorMdd(4)
 
Downstream Bonded Channels
ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
1LockedQAM25625579000000 Hz11.7 dBmV37 dB75070
2LockedQAM25626585000000 Hz11.4 dBmV36.9 dB88350
3LockedQAM25627591000000 Hz11.4 dBmV36.8 dB99760
4LockedQAM25628597000000 Hz11.3 dBmV36.8 dB101240
5LockedQAM25629603000000 Hz11.2 dBmV36.7 dB117000
6LockedQAM25630609000000 Hz11.2 dBmV36.6 dB109950
7LockedQAM25631615000000 Hz10.9 dBmV36.5 dB141780
8LockedQAM25632621000000 Hz11 dBmV36.5 dB148870
9LockedQAM25633627000000 Hz10.9 dBmV36.4 dB151720
10LockedQAM25634633000000 Hz10.7 dBmV36.2 dB183900
11LockedQAM25635639000000 Hz10.7 dBmV36.2 dB195610
12LockedQAM25636645000000 Hz10.6 dBmV36.2 dB208710
13LockedQAM25637651000000 Hz10.7 dBmV36.2 dB197640
14LockedQAM25638657000000 Hz10.7 dBmV36.1 dB211120
15LockedQAM25639663000000 Hz10.7 dBmV36.1 dB225160
16LockedQAM25640669000000 Hz10.8 dBmV36.1 dB227780
 
Upstream Bonded Channels
ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA105120 Ksym/sec29200000 Hz50 dBmV
2LockedATDMA95120 Ksym/sec35600000 Hz50.5 dBmV
3LockedATDMA115120 Ksym/sec22800000 Hz50.5 dBmV
4LockedATDMA125120 Ksym/sec16400000 Hz49 dBmV
 
Extended Upstream Transmit Power
Enable Extended Upstream Transmit Power
 
Current System Time:Sat Oct 24 18:21:50 2020
System Up Time:00:31:23
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Expert

Re: Constant Disonnects

The upstream power is too high and it may be intermittently fluctuating even higher to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test.

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.


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Re: Constant Disonnects

The tech was just out here this morning and he said he actually lowered the levels beacause they were too high. Regarding the splitters, as i mentioned already i have removed already which does not seem to have made any difference.

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Expert

Re: Constant Disonnects

If the tech visit was before you posted that upstream power level, then it wasn't enough..... it wasn't even enough for the downstream. You were conned.


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Re: Constant Disonnects

i guess so. where do i want that range to be within to have more stability.

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Re: Constant Disonnects

40 to 45 dB is preferred. Here are the specs;

 

Specification      Min             Max

Downstream Power Level  
Cable Modems-10dBmV+10dBmV
Gateways and EMTAs-7dBmV+7dBmV
Downstream Signal to Noise Ratio35dB-
Upstream Power Level+35dBmV+50dBmV
Upstream Signal to Noise Ratio31dB-
Upstream Receive Power-2dBmV+2dBmV

 



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Re: Constant Disonnects

so the 40-45 db i imagine you are referring to the upstream? maybe the tech only adjusted the downstream as it seems closer to the 35 reccomended. are there any other values that look like they need to be adjusted?

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Re: Constant Disonnects


@riehs wrote:

so the 40-45 db i imagine you are referring to the upstream?

 

Yes.

 

maybe the tech only adjusted the downstream as it seems closer to the 35 reccomended.

 

That's not the power level for the downstream.. It's the SNR. They can't just adjust that. They need to do things to the line to get it as high as possible.

 

are there any other values that look like they need to be adjusted?

 

No.


 



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