Calibrate Power Levels

Question

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 ID	Lock Status	Modulation	Frequency	Power	SNR/MER	Corrected	Uncorrectables
9	Locked	QAM256	507000000 Hz	-7.4 dBmV	39.8 dB	0	0
1	Locked	QAM256	453000000 Hz	-7.9 dBmV	39.6 dB	0	0
2	Locked	QAM256	459000000 Hz	-7.8 dBmV	39.6 dB	0	0
3	Locked	QAM256	465000000 Hz	-8.0 dBmV	39.4 dB	0	0
4	Locked	QAM256	471000000 Hz	-7.7 dBmV	39.6 dB	0	0
5	Locked	QAM256	477000000 Hz	-7.5 dBmV	39.7 dB	0	0
6	Locked	QAM256	483000000 Hz	-7.5 dBmV	39.6 dB	0	0
7	Locked	QAM256	489000000 Hz	-7.2 dBmV	39.8 dB	0	0
8	Locked	QAM256	495000000 Hz	-7.3 dBmV	39.7 dB	0	0
10	Locked	QAM256	513000000 Hz	-7.6 dBmV	39.6 dB	0	0
11	Locked	QAM256	519000000 Hz	-7.9 dBmV	39.5 dB	0	0
12	Locked	QAM256	525000000 Hz	-8.3 dBmV	39.3 dB	0	0
13	Locked	QAM256	531000000 Hz	-8.4 dBmV	39.2 dB	0	0
14	Locked	QAM256	537000000 Hz	-8.8 dBmV	39.1 dB	0	0
15	Locked	QAM256	543000000 Hz	-8.4 dBmV	39.1 dB	0	0
16	Locked	QAM256	549000000 Hz	-8.9 dBmV	38.9 dB	0	0
17	Locked	QAM256	555000000 Hz	-8.4 dBmV	39.1 dB	0	0
18	Locked	QAM256	561000000 Hz	-8.5 dBmV	39.2 dB	0	0
19	Locked	QAM256	567000000 Hz	-8.2 dBmV	39.2 dB	0	0
20	Locked	QAM256	573000000 Hz	-8.0 dBmV	39.5 dB	0	0
21	Locked	QAM256	579000000 Hz	-7.8 dBmV	39.5 dB	0	0
22	Locked	QAM256	585000000 Hz	-7.4 dBmV	39.6 dB	0	0
23	Locked	QAM256	591000000 Hz	-7.3 dBmV	39.8 dB	0	0
37	Locked	Other	690000000 Hz	-8.6 dBmV	35.8 dB	323718853	0
38	Not Locked	QAM256	0 Hz	0.0 dBmV	40.4 dB	0	0
39	Locked	QAM256	423000000 Hz	-6.7 dBmV	40.2 dB	0	0
40	Locked	QAM256	429000000 Hz	-7.1 dBmV	40.1 dB	0	0
41	Locked	QAM256	435000000 Hz	-6.9 dBmV	39.7 dB	0	0
42	Locked	QAM256	447000000 Hz	-7.6 dBmV	40.3 dB	0	0
43	Locked	QAM256	399000000 Hz	-6.7 dBmV	40.3 dB	0	0
44	Locked	QAM256	405000000 Hz	-6.6 dBmV	40.3 dB	0	0
45	Locked	QAM256	411000000 Hz	-6.7 dBmV	40.3 dB	0	0

Upstream Bonded Channels

Channel	Channel ID	Lock Status	US Channel Type	Frequency	Width	Power
1	3	Locked	SC-QAM Upstream	22800000 Hz	6400000 Hz	42.0 dBmV
2	1	Locked	SC-QAM Upstream	35600000 Hz	6400000 Hz	43.0 dBmV
3	2	Locked	SC-QAM Upstream	29200000 Hz	6400000 Hz	43.0 dBmV
4	4	Locked	SC-QAM Upstream	16400000 Hz	6400000 Hz	41.0 dBmV
5	5	Locked	SC-QAM Upstream	39600000 Hz	1600000 Hz	43.0 dBmV

DaElephant · Answer

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.

CCAndrew · Answer

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.

DaElephant · Answer

@CCAndrewThere 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

CCAndrew · Answer

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?

DaElephant · Answer

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.

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Calibrate Power Levels

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