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Low Speeds, factory reset on all equipment, low SNR?

New Poster

Low Speeds, factory reset on all equipment, low SNR?

Hey all,

I've been having issues for about a week now with extremely slow speeds, I was already getting slow speeds at 30mb down when I am supposed to be receiving 80mb down; However, now I am receiving 2-5mb down with fluxuations up to 30 at random. I have done factory resets on all the equipment, I recently purchased a new router and modem, the modem being a CM500, which it looks like there have been issues with, (might be going out soon to grab a Linksys modem.)

 

I want to also mention I recently got my IP address changed just to be sure everything else checked out.

 

Here are the Channels below:

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 17 705000000 Hz -6.2 dBmV 39.5 dB 0 0
2 Locked QAM256 9 657000000 Hz -5.4 dBmV 28.4 dB 5570190 422085
3 Locked QAM256 10 663000000 Hz -4.9 dBmV 34 dB 7389 282
4 Locked QAM256 11 669000000 Hz -5.5 dBmV 39.7 dB 0 0
5 Locked QAM256 12 675000000 Hz -5.4 dBmV 39.4 dB 0 0
6 Locked QAM256 13 681000000 Hz -5.7 dBmV 39.8 dB 0 0
7 Locked QAM256 14 687000000 Hz -6 dBmV 34 dB 0 0
8 Locked QAM256 15 693000000 Hz -5.3 dBmV 36.3 dB 0 0
9 Locked QAM256 16 699000000 Hz -5.6 dBmV 39.9 dB 0 0
10 Locked QAM256 18 711000000 Hz -6.2 dBmV 39.4 dB 0 0
11 Locked QAM256 19 717000000 Hz -7.2 dBmV 38.9 dB 0 0
12 Locked QAM256 20 723000000 Hz -6.9 dBmV 38.9 dB 0 0
13 Locked QAM256 21 729000000 Hz -5.8 dBmV 36.1 dB 4 0
14 Locked QAM256 22 735000000 Hz -5.3 dBmV 33.8 dB 538961 181259
15 Locked QAM256 23 741000000 Hz -5.4 dBmV 29 dB 75400 121828
16 Locked QAM256 24 747000000 Hz -7.5 dBmV 33.6 dB 2463 1
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 Ksym/sec 36800000 Hz 48.5 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 30400000 Hz 48.5 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 24000000 Hz 46.5 dBmV

 

I noticed that at certain times the locked status would go to unlocked and some of these would be different of course.

 

I also noticed from previous searching that I have some low channels under 35 dB, I have addressed with comcast that I believe the lines on the outside are causing this issue, but I am unsure entirely if it's on the outside now, or if it's something to do with the cabeling inside, (which I don't think is the case.)

 

Would it be wise to also purchase a new modem instead of the CM500?

 

Thanks

Diamond Problem Solver

Re: Low Speeds, factory reset on all equipment, low SNR?

The downstream power is on the weak side and the SNR is low to out of spec on some of the channels. And the upstream power is on the high side and may be intermittently fluctuating even higher out of spec. That can cause random disconnects, spontaneous re-booting of the modem, and speed and latency problems.

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.


Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home.

New Poster

Re: Low Speeds, factory reset on all equipment, low SNR?

Right, normally it starts at home; however, we had a tech come out, and they came in, did something, and then left, with charging us a $60 fee. Reported it, and got that refunded as nothing came from that and we still experienced slow speeds.

 

I've insisted that it's lines on the outside,

 

Here are the up&down stream of what tonight is...

 

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 17 705000000 Hz -5.2 dBmV 39.9 dB 2826863 1009398
2 Locked QAM256 9 657000000 Hz -4.4 dBmV 27.6 dB 1952959 111635
3 Locked QAM256 10 663000000 Hz -3.8 dBmV 35.1 dB 1113124 652935
4 Locked QAM256 11 669000000 Hz -4.5 dBmV 39.9 dB 2010479 2392658
5 Locked QAM256 12 675000000 Hz -4.9 dBmV 39.4 dB 2425804 2303868
6 Locked QAM256 13 681000000 Hz -5.6 dBmV 39.8 dB 3421786 2431544
7 Locked QAM256 14 687000000 Hz -6 dBmV 34.4 dB 8394014 2021026
8 Locked QAM256 15 693000000 Hz -5.6 dBmV 34.8 dB 5594994 2093981
9 Locked QAM256 16 699000000 Hz -5.6 dBmV 39.9 dB 4084814 1127243
10 Locked QAM256 18 711000000 Hz -4.3 dBmV 40 dB 2308255 1480227
11 Locked QAM256 19 717000000 Hz -4.4 dBmV 39.9 dB 1957423 1494551
12 Locked QAM256 20 723000000 Hz -3.8 dBmV 39.9 dB 1667845 1501728
13 Locked QAM256 21 729000000 Hz -3.5 dBmV 37.1 dB 1579062 1733256
14 Locked QAM256 22 735000000 Hz -4 dBmV 34.4 dB 13392573 4330489
16 Locked QAM256 24 747000000 Hz -7.3 dBmV 34.5 dB 9070450 1818121
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 Ksym/sec 36800000 Hz 47 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 30400000 Hz 47 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 24000000 Hz 45 dBmV

 

I've consistently seen Channel 2 being low and everything else being just barely okay, Question is, would swapping from a CM500 router to a CM3024 Router make any difference with the CM3024 router having more downstream channels? (As a possible temporary fix till Comcast comes out...)

 

It's like pulling teeth to get comcast out here, I've had so many bad experiences with the tech's that I find them inconsistent, lacking knowledge, and overall just terrible at moving towards the 2nd stage of my issue apparently...

 

New Poster

Re: Low Speeds, factory reset on all equipment, low SNR?

Update: I am having a tech come out tomorrow to help with this issue.

Diamond Problem Solver

Re: Low Speeds, factory reset on all equipment, low SNR?

Good luck !! Post back about how things turn out.