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Calibrate Power Levels

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Regular Visitor

Calibrate Power Levels

I have a SB8200 with connection issues and random slow speeds.  I am trying to get my power levels calibrated as stated by the Arris customer support (Downstream between 15dBmV and -15dBmV but as close to 0 as possible / Upstream between 45dBmV and 51dBmV.   One channel is not locked and the other has correctable and uncorrectable errors (uncorrectable not showing because I rebooted the modem right before taking a screenshot).  The Event Log is geting errors randomly throughtout the day.  According to Arris support Comcast/Xfinity should be able to calibrate my signal levels remotely.  How do I get them to do this?  I had a tech come out.  He added a splitter but issues remain.  I have been on chat and the phone many times with tech support only to still have issues.

 

Downstream Bonded Channels
Channel IDLock StatusModulationFrequencyPowerSNR/MERCorrectedUncorrectables
9LockedQAM256507000000 Hz-7.4 dBmV39.8 dB00
1LockedQAM256453000000 Hz-7.9 dBmV39.6 dB00
2LockedQAM256459000000 Hz-7.8 dBmV39.6 dB00
3LockedQAM256465000000 Hz-8.0 dBmV39.4 dB00
4LockedQAM256471000000 Hz-7.7 dBmV39.6 dB00
5LockedQAM256477000000 Hz-7.5 dBmV39.7 dB00
6LockedQAM256483000000 Hz-7.5 dBmV39.6 dB00
7LockedQAM256489000000 Hz-7.2 dBmV39.8 dB00
8LockedQAM256495000000 Hz-7.3 dBmV39.7 dB00
10LockedQAM256513000000 Hz-7.6 dBmV39.6 dB00
11LockedQAM256519000000 Hz-7.9 dBmV39.5 dB00
12LockedQAM256525000000 Hz-8.3 dBmV39.3 dB00
13LockedQAM256531000000 Hz-8.4 dBmV39.2 dB00
14LockedQAM256537000000 Hz-8.8 dBmV39.1 dB00
15LockedQAM256543000000 Hz-8.4 dBmV39.1 dB00
16LockedQAM256549000000 Hz-8.9 dBmV38.9 dB00
17LockedQAM256555000000 Hz-8.4 dBmV39.1 dB00
18LockedQAM256561000000 Hz-8.5 dBmV39.2 dB00
19LockedQAM256567000000 Hz-8.2 dBmV39.2 dB00
20LockedQAM256573000000 Hz-8.0 dBmV39.5 dB00
21LockedQAM256579000000 Hz-7.8 dBmV39.5 dB00
22LockedQAM256585000000 Hz-7.4 dBmV39.6 dB00
23LockedQAM256591000000 Hz-7.3 dBmV39.8 dB00
37LockedOther690000000 Hz-8.6 dBmV35.8 dB3237188530
38Not LockedQAM2560 Hz0.0 dBmV40.4 dB00
39LockedQAM256423000000 Hz-6.7 dBmV40.2 dB00
40LockedQAM256429000000 Hz-7.1 dBmV40.1 dB00
41LockedQAM256435000000 Hz-6.9 dBmV39.7 dB00
42LockedQAM256447000000 Hz-7.6 dBmV40.3 dB00
43LockedQAM256399000000 Hz-6.7 dBmV40.3 dB00
44LockedQAM256405000000 Hz-6.6 dBmV40.3 dB00
45LockedQAM256411000000 Hz-6.7 dBmV40.3 dB00


 

 
Upstream Bonded Channels
ChannelChannel IDLock StatusUS Channel TypeFrequencyWidthPower
13LockedSC-QAM Upstream22800000 Hz6400000 Hz42.0 dBmV
21LockedSC-QAM Upstream35600000 Hz6400000 Hz43.0 dBmV
32LockedSC-QAM Upstream29200000 Hz6400000 Hz43.0 dBmV
44LockedSC-QAM Upstream16400000 Hz6400000 Hz41.0 dBmV
55LockedSC-QAM Upstream39600000 Hz1600000 Hz43.0 dBmV
Highlighted
Regular Visitor

Re: Calibrate Power Levels

To add to this.

 

I have confirmed it is not an issue within my home.  I checked the signal levels at the box on the side of the house with almost the excact same levels and problems.

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Diamond Problem Solver

Re: Calibrate Power Levels

There is no such thing as remote calibration, any adjustments are made on site by maintenance if deemed necessary.
A tech adding a splitter is taking you further from zero, it adds to the upstream but takes away from downstream
Comcast uses its own range of signal levels, it doesn’t matter what Arris said. Everything is in Comcast’s specs except for that one channel not locking in and bad SNR on another. You’ll probably need a second tech, if you have negative downstream levels entering the house and you are sure there are no other splitters.

I am a Retired Official Comcast Employee
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Regular Visitor

Re: Calibrate Power Levels

@CCAndrew

There are 2 splitters.  That is the only way I can keep my internet from crashing every few minutes.

 

Since the tech comes out power cycles the modem then runs a speed test with good results, how do I convince them there is still a problem?

 

Also, if Comcast has there own specs why are the levels in the troubleshooting video exactly where mine need to be (about -4 Downstream and 48 Upstream)?

 

https://www.youtube.com/watch?v=cGmKbNGzJKM

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Diamond Problem Solver

Re: Calibrate Power Levels

Whoever made the video, it just so happens that they’re personal levels. Not everyone is going to be exactly the same. There’s all kinds of ways to manipulate an upstream/downstream signal, you’re using a splitter. It’s a balance between the two. Like I said above, take their modem and try it, keep in contact with the local techs/supervisor.

If you’re missing a downstream channel and bad SNR on another, those aren’t good results. What are your levels at the ground block or before any splitters? It’s just part of troubleshooting. Also, what type of splitters, 2,3,4,8 way?

I am a Retired Official Comcast Employee
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Regular Visitor

Re: Calibrate Power Levels

It appears they flashed a new firmware or boot file. I noticed the software version is different and the connection so far is working.
@CCAndrew - Thank you for your time.