hi could a tech check my power levels
Forum Discussion
10 Replies
You can do this ...
Downstream Power Levels of -7 to +7 dBmV are preferred, +10dBmV is the max acceptable, with a SNR of 33dB or higher across all DOCSIS 3.0 channels. Rising error counts across many channels is a current service noise fault.
Upstream Power Levels of 35 to 49 dBmV are preferred, with QAM 64 Modulation mode across all four to six DOCSIS 3.0 channels. Seeing QAM 32/16/QPSK is a current service noise fault. Seeing less than four DOCSIS 3.0 channels is usually a signal level fault.it wont let me post any graphics. html error.
Cable Modem Diagnostic Report
Date: 08-Nov-2025
Device MAC:
CMTS MAC:
DOCSIS Version: 3.1
QoS Version: 1.1------------------------------------------------------------
1. Summary of Findings
------------------------------------------------------------
Upstream Power: Levels within optimal range (≈43 dBmV for D3.0, 38 dBmV for D3.1) - Normal
Upstream Modulation: D3.0 channels operating at QAM 32 (expected QAM 64) - Moderate
OFDMA Channel (D3.1): Stable, full QAM 256 modulation, 0 timeouts - Normal
Timeouts (T1–T4): All zero across all channels - Normal
Log Activity: Continuous “US profile assignment change” messages on Channel ID 11 - Moderate
DHCP: One instance of “DHCP RENEW WARNING” - Low------------------------------------------------------------
2. Log Review
------------------------------------------------------------
Repeated pattern:
US profile assignment change. US Chan ID: 11; Previous Profile: 11 13; New Profile: 12 13;
and
US profile assignment change. US Chan ID: 11; Previous Profile: 12 13; New Profile: 11 13;Interpretation:
OFDMA upstream Channel 11 is switching between modulation profiles due to slight SNR variation.
Single DHCP warning observed (not critical).------------------------------------------------------------
3. Upstream Channel Statistics
------------------------------------------------------------
DOCSIS 3.0 Channels (ATDMA)
Power ≈43 dBmV, Modulation QAM 32, Timeouts 0 across all 5 channels.
QAM 32 suggests minor upstream noise or ingress.DOCSIS 3.1 Channel (OFDMA)
Channel ID 11, Power 38.2 dBmV, Modulation QAM 256, Timeouts 0.
Healthy and stable.------------------------------------------------------------
4. Technical Interpretation
------------------------------------------------------------
- Profile flapping = CMTS adjusting OFDMA modulation profiles due to variable upstream SNR.
- D3.0 QAM 32 = reduced modulation, mild SNR degradation.
- Power levels = consistent and healthy.
- No connectivity loss (0 T1–T4).------------------------------------------------------------
5. Recommended Actions
------------------------------------------------------------
1. Check all coax connectors and splitters for corrosion or looseness.
2. Ask ISP to check return-path MER/SNR for OFDMA Channel ID 11.
3. Monitor logs for 24–48 hours to see if profile flapping continues.
4. Remove unnecessary splitters to improve upstream power.
5. Reboot modem once to clear DHCP warning.------------------------------------------------------------
6. Overall Assessment
------------------------------------------------------------
Service Health: Stable
Primary Concern: Minor upstream SNR fluctuation (profile changes and QAM 32 fallback)
Next Step: Have ISP verify upstream MER and noise ingress on Channel 11.
------------------------------------------------------------
Good we can not read the tiny screen shot images !
Copy / Paste the text of the Upstream / Downstream tabs.
Also mention what problem you are encountering.I am confused.
The "Cable Modem Diagnostic Report" and the DOCSIS stats do not tally.Yes, report states QAM 32, but log shows QAM 64? Nothing amiss with those levels apart from the DS power is pushing the upper limits of +10.
thanks i was using chatgpt for some help.. does all look good>? i did a reset 3 days ago as i was getting some packet loss..
Setup a BQM to monitor your circuit. http://www.thinkbroadband.com/ping
Your power levels at present are within spec.
