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Tuesday, February 14th, 2023 3:41 AM

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Extremely Slow Download Speeds

Hello,

Starting around a month ago, my download speeds dropped from ~300 mbps to a ~5-10mbps. At the time, I was told that my modem was out of spec as I our speed was recently upgraded across the network, and so I upgraded to a DOCSIS 3.1 modem, ASUS SB8200. After upgrading, my speeds were even faster than before reaching above 300 mbps. However, in the past few days, the speed to returned to the lows of a consistent 5-15 mbps.

Based on my initial research, and based on what phone support told me, it looks like my downstream channels are awfully low power.

Any advice or insight is appreciated.

Here are the numbers from the modems status page:

Downstream Bonded Channels
Channel ID Lock Status Modulation Frequency Power SNR/MER Corrected Uncorrectables
20 Locked QAM256 543000000 Hz -22.7 dBmV 26.5 dB 2144539 57154
13 Locked QAM256 501000000 Hz -15.5 dBmV 33.1 dB 0 0
14 Locked QAM256 507000000 Hz -14.8 dBmV 33.3 dB 1 0
15 Locked QAM256 513000000 Hz -16.2 dBmV 30.6 dB 15 0
16 Locked QAM256 519000000 Hz -16.6 dBmV 32.6 dB 1 0
17 Locked QAM256 525000000 Hz -16.7 dBmV 32.9 dB 9 0
18 Locked QAM256 531000000 Hz -18.4 dBmV 30.3 dB 114 0
19 Locked QAM256 537000000 Hz -18.2 dBmV 27.7 dB 47747 5588
21 Locked QAM256 549000000 Hz -23.1 dBmV 0.0 dB 288757 0
22 Not Locked Unknown 555000000 Hz -24.0 dBmV 0.0 dB 305452 0
23 Locked QAM256 561000000 Hz -21.6 dBmV 28.4 dB 18755 0
24 Locked QAM256 567000000 Hz -21.4 dBmV 28.4 dB 19947 0
25 Not Locked Unknown 573000000 Hz -25.5 dBmV 0.0 dB 0 0
26 Not Locked Unknown 579000000 Hz -26.4 dBmV 0.0 dB 0 0
27 Not Locked Unknown 585000000 Hz -27.6 dBmV 0.0 dB 0 0
28 Not Locked Unknown 591000000 Hz -26.2 dBmV 0.0 dB 0 0
29 Locked QAM256 597000000 Hz -25.1 dBmV 0.0 dB 825 0
30 Locked QAM256 603000000 Hz -21.4 dBmV 28.4 dB 16292 0
31 Locked QAM256 609000000 Hz -22.9 dBmV 26.3 dB 5275039 1313613
32 Not Locked Unknown 615000000 Hz -28.1 dBmV 0.0 dB 0 0
33 Not Locked Unknown 621000000 Hz -34.2 dBmV 0.0 dB 0 0
34 Not Locked Unknown 627000000 Hz -34.5 dBmV 0.0 dB 0 0
35 Not Locked Unknown 633000000 Hz -34.9 dBmV 0.0 dB 0 0
36 Not Locked Unknown 639000000 Hz -28.5 dBmV 0.0 dB 0 0
37 Not Locked Unknown 645000000 Hz -26.8 dBmV 0.0 dB 0 0
38 Locked QAM256 651000000 Hz -25.4 dBmV 0.0 dB 4049 0
39 Not Locked Unknown 657000000 Hz -30.7 dBmV 0.0 dB 0 0
40 Not Locked Unknown 663000000 Hz -33.6 dBmV 0.0 dB 0 0
41 Not Locked Unknown 669000000 Hz -27.6 dBmV 0.0 dB 0 0
42 Not Locked Unknown 675000000 Hz -28.8 dBmV 0.0 dB 0 0
43 Not Locked Unknown 681000000 Hz -31.3 dBmV 0.0 dB 0 0
44 Not Locked Unknown 687000000 Hz -28.4 dBmV 0.0 dB 0 0
193 Locked Other 957000000 Hz -2.2 dBmV 0.0 dB 0 0


Upstream Bonded Channels
Channel Channel ID Lock Status US Channel Type Frequency Width Power
1 1 Locked SC-QAM Upstream 16400000 Hz 6400000 Hz 49.0 dBmV
2 2 Locked SC-QAM Upstream 22800000 Hz 6400000 Hz 50.0 dBmV
3 3 Locked SC-QAM Upstream 29200000 Hz 6400000 Hz 50.0 dBmV
4 4 Locked SC-QAM Upstream 35600000 Hz 6400000 Hz 50.0 dBmV


Accepted Solution

Expert

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110.1K Messages

2 years ago

Yep. The downstream power levels and the SNR's are too low /out of spec. And the upstream power is almost out of spec. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

In an 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 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, Target, etc. Splitters should be swapped with known to be good / new ones to test.

Also check the coax cable for any damage such as cuts, nicks, abrasions, kinks, sharp bends, etc.

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.


Good luck with it !

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