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Consistent Outages, Modem Status attached

New Poster

Consistent Outages, Modem Status attached

I bought the fastest tier available to my location (Bay Area, California), extreme 250, and have been getting good speeds. Reliability however has been abysmal at best. The internet always goes out at random times and calls to customer service has been pointless (sir, please reset your modem, sir please make sure the connections are tight, sir your modem is probably broken etc). I personally ran the Belden RG-6Q lines to the service termination, I have been using a belden cat 6 ethernet cable directly from my SB8200 modem to my desktop as well, so I know it's not my equipment. The tech who came said the signal to the modem was too strong so he put an attenutator on the line. The problem is, I am still getting random outages and when I call comcast to report an outage, they say "We dont have any reports of any outages in your area", no kidding, that's why I am calling to report one!

 

Just to be certain, I bought another SB8200 so they can't blame my modem. With the attenuator and the new modem, I am not seeing any more unccorrectables except there is one anomoly with channel 33, the modulation is "other", the SNR seems bad, and there is still uncorrectables. Still getting the random service outages. 

 

 

xfinity downstream.jpgxfinity upstream.jpg

 

Any ideas on what the problem is?

Expert

Re: Consistent Outages, Modem Status attached


@TO_XFINITI wrote:

I am not seeing any more unccorrectables except there is one anomoly with channel 33, the modulation is "other", the SNR seems bad, and there is still uncorrectables. Still getting the random service outages. 


That is normal to say "Other" in that it is the DOCSIS 3.1 OFDM modulated / PLC downstream channel. Some models of modems display it as the latter, some models display it as just "Other".

 

And yes the SNR on it is out of spec on it. The downstream power is still high. Perhaps you should get the techs back out there until they fix it right.

Expert

Re: Consistent Outages, Modem Status attached

Channel 33 is for DOCSIS 3.1, it's normal for it to show uncorrectables. Your problem is that your upstream is out of spec. You can't attenuate the return path (upstream).  Your last tech needs a little more training. There is no way for you to fix this on your own. You'll need another tech. 

 

I've asked a Comcast employee to help you. You should expect a reply in this thread. 

 

FYI: They owe you a $20 credit for every tech visit after the first for the same problem.You can also get a credit for your service from the time you first reported the issue until it is resolved.

Expert

Re: Consistent Outages, Modem Status attached


@EG wrote:

And yes the SNR on it is out of spec on it. The downstream power is still high. Perhaps you should get the techs back out there until they fix it right.

LOL EG is faster than me as usual 

Expert

Re: Consistent Outages, Modem Status attached


@nerdburg wrote:


LOL EG is faster than me as usual 


Darn echoes.... LOLLLL !!! 

New Poster

Re: Consistent Outages, Modem Status attached

If the downstream power is still high, would adding a stronger attenuator or adding a splittler along with the attenuator solve the problem? what is the most optimal down and upstream power level?

Expert

Re: Consistent Outages, Modem Status attached

You could try adding a 6 dB attenuator to what is already there. 0 dB down is ideal. 40-45 dB up is ideal.

Expert

Re: Consistent Outages, Modem Status attached


@TO_XFINITI wrote:

If the downstream power is still high, would adding a stronger attenuator or adding a splittler along with the attenuator solve the problem? what is the most optimal down and upstream power level?


You can knock the downstream down with an attenuator, but it's only part of the problem. You can't fix this on your own. 

 

Specification      Min             Max
Downstream Power Level    
* Cable Modems -10dBmV +10dBmV
* Gateways and EMTAs -7dBmV +7dBmV
Downstream Signal to Noise Ratio 35dB 50dB
Upstream Power Level +35dBmV +50dBmV
Upstream Signal to Noise Ratio 31dB -
Upstream Receive Power -2dBmV +2dBmV
New Poster

Re: Consistent Outages, Modem Status attached

Thanks EG and NerdBurg, honestly if they could just send me a tech who knows what theyre doing like you guys, I wouldn't mind paying extra for a seasoned tech to get the fastest possible speed and reliability. The frustrating thing is that I do not know enough about modem specs power, SNR, and uncorrectables to correct the techs when they get here, yet I know enough that it annoys me when customer services wastes my time going through the procedure list of power cycles and that there is something wrong with the tightness of my connections.

 

What's the optimal  levels for dBmV, SNR, and freqs for upstream and downstream? That way before the second tech leaves, I can make sure on the modem status page that everything is fine and copacetic. 

 

Also, what would likely be causing these issues? 

 

Edit: thanks guys! beat me to the punch.

 

So I should be looking for 0dBmV for downstream, 40dBmV for upstream power. The SNR should be higher, closer to 40db and above rather than hovering right over the 35 min mark.

Expert

Re: Consistent Outages, Modem Status attached

Show them this thread.

Expert

Re: Consistent Outages, Modem Status attached


@TO_XFINITI wrote:

 

Also, what would likely be causing these issues? 


Your signal is too "hot. Downstream is too high, upstream is too low. It needs to be addressed by a maintenance tech. Your next tech won't be able to fix it either, but he will start the process to get this fixed properly. If at any point you are unhappy with how it's being resolved, let the team here know and they will make sure it gets fixed properly. Keep us updated Smiley Happy

New Poster

Re: Consistent Outages, Modem Status attached

Thanks guys, this is awesome! I have been going crazy these past two years I lived here trying to figure out what the heck is wrong with my internet, buying the best modem, replacing the cable lines, but it seems that this is something that is out of my hands.

 

I just made the call, a technician will come out tomorrow, I will print out this thread so he can go through it and see whats going on. Since nerdburg said a regular tech may not be able to solve this, I wonder if he's just going to show up, read the thread, say "yup, time to call the other guy" and just leave (I mean, what can he do? how does main. techs adjust power levels? at the termination junction? at the central office?)

Official Employee

Re: Consistent Outages, Modem Status attached

Hi TO_XFINITI, I can make sure we get the right tech sent out to you. First I need to verify your account information so that I can take a deeper look into your work order, please send me a private message with your full name, street address, and account number by clicking on my name (ComcastAmir) and then "private message me" and we can get started.