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Low Upstream Channel Power

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Diamond Problem Solver

Re: Low Upstream Channel Power


@Jireland90 wrote:

 Also in your opinion is it better to have a router+modem or two separate units? The one I have now is a combo. 


There is always an inherent disadvantage with these. Combo gateway devices are always a compromise in both quality and performance compared to separate units. Also, only the ISP can update the firmware so you are always a prisoner of that / them. And the firmware is typically crippled by the ISP's customizing of it and they typically eliminate valuable features.

One of the biggest issues with them is that it is far more difficult to diagnose connectivity issues when it comes to troubleshooting. You can't narrow things down by using the process of elimination by removing just the router from the path. And if either segment fails / malfunctions, you have a total failure. I think that CC made a big mistake when they changed their policy and decided to start supplying them instead of dedicated devices. 

Get separate units and keep the control of your home network in your hands instead of theirs, you'll be much happier !



Expert

Re: Low Upstream Channel Power


@Jireland90 wrote:

I can't thank you guys enough on clarifying all of this for me. The thing that was bothering me the most was both companies werent really giving me an answer, just placing the blame on the other guy. All I wanted was "you need a different modem BECAUSE..." I think that I will try a new modem and see if that remedies my issue. I'll start shopping tonight. Any recommendations on one to get? Also in your opinion is it better to have a router+modem or two separate units? The one I have now is a combo. Thanks again guys!

-John


You get a lot more control and flexibility with getting separate units, plus if one fails, the other will still keep going.

On the other hand, having a gateway is a lot more convenient, and simpler to setup and manage.

Depends on what you feel is right for you. 

 

You'll find varying opinions on what the best modems, routers, or gateways are, but these are my personal recommendationsfor your speed tier:

 

Modem: ARRIS SB6183 

Router: TP Link Archer C7 (good), ASUS RT-AC86U (better), Eero WiFi mesh (best).

Gateway: Netgear C7000 or Motorola MG7550 

 


Comcast Experts are other customers who volunteer their time helping on the forum and have been recognized by the community. For more information on the Expert Program, please click here.
Unless so specifically stated, my opinions written herein are my own and do not necessarily reflect the views of Comcast, its official employees or affiliates.
New Poster

Re: Low Upstream Channel Power

I can't thank you guys enough on clarifying all of this for me. The thing that was bothering me the most was both companies werent really giving me an answer, just placing the blame on the other guy. All I wanted was "you need a different modem BECAUSE..." I think that I will try a new modem and see if that remedies my issue. I'll start shopping tonight. Any recommendations on one to get? Also in your opinion is it better to have a router+modem or two separate units? The one I have now is a combo. Thanks again guys!

-John

Gold Problem Solver

Re: Low Upstream Channel Power


@Jireland90 wrote: Ok. That should then allow me to get that 215 though? ...

Minor correction: Comcast rates the SBG6580-2 for a max of 207 Mbps -- see https://mydeviceinfo.xfinity.com/device/arris-sbg6580-2-533.

 

For any tier above 200 Mbps, you need a faster modem. Also, your downstream levels are too high, and the error log suggests that there may be other signal problems. If a new modem doesn't correct those, you'll need to have Comcast come back out to locate the trouble and correct it. Here's hoping you get someone competent this time!

Diamond Problem Solver

Re: Low Upstream Channel Power


@Jireland90 wrote:

Ok. That should then allow me to get that 215 though? Right now I'm only getting around 50 with an ethernet connection, 30 over wifi.

Thanks,

John


What happens is if a modem is not compatible with a particular faster speed tier, it will default to using only a Performance speed tier configuration / bootfile.

Expert

Re: Low Upstream Channel Power

It should. Sounds like the configuration file on the modem might be incorrect. Have you done a factory reset on the gateway? (Bent paperclip on the hidden Reset button on the back for 30 seconds)


Comcast Experts are other customers who volunteer their time helping on the forum and have been recognized by the community. For more information on the Expert Program, please click here.
Unless so specifically stated, my opinions written herein are my own and do not necessarily reflect the views of Comcast, its official employees or affiliates.
New Poster

Re: Low Upstream Channel Power

Ok. That should then allow me to get that 215 though? Right now I'm only getting around 50 with an ethernet connection, 30 over wifi.

Thanks,

John

Expert

Re: Low Upstream Channel Power


@Jireland90 wrote:

I just recently upgraded to Blast Tier which I believe is 250 mbps download. My modem is an Arris SBG6580-2 which comcast told me is compatible with their service. Capable of download speeds 300 mbps Wifi and 350 mbps ethernet.


@BruceW is right. Your gateway isn't rated for the speed tier you've subscribed to - Comcast has it for 215 Mbps max - 

 

https://mydeviceinfo.xfinity.com/device/arris-sbg6580-268

 

 


Comcast Experts are other customers who volunteer their time helping on the forum and have been recognized by the community. For more information on the Expert Program, please click here.
Unless so specifically stated, my opinions written herein are my own and do not necessarily reflect the views of Comcast, its official employees or affiliates.
New Poster

Re: Low Upstream Channel Power

I just recently upgraded to Blast Tier which I believe is 250 mbps download. My modem is an Arris SBG6580-2 which comcast told me is compatible with their service. Capable of download speeds 300 mbps Wifi and 350 mbps ethernet. Here is the event log. Really appreciate you helping me out with this.

image.pngThanks,

John

Gold Problem Solver

Re: Low Upstream Channel Power


@Jireland90 wrote: ... The ethernet is about 20 mbps faster than the wifi but that is still only 50 mbps ...

We need to know your modem model number and what Comcast Internet speed tier you subscribe to. Could you please post the event log as well? If your gateway is only an 8/4 model it may not be rated for 300 Mbps service -- see https://mydeviceinfo.xfinity.com/.

New Poster

Re: Low Upstream Channel Power

I have tried both ethernet and wifi. The ethernet is about 20 mbps faster than the wifi but that is still only 50 mbps, 30 mbps wifi. The field tech hooked up his modem and it was showing 300 mbps. Went back to mine and it was back down to 50 mbps. This is the only reason I have trouble trusting that Arris is correct in saying that it is something on Xfinity's end. Here is the connection page from my modem. On the event log I have multiple "T3 Time-out" errors. Thank you for the reply.

-John

 

image.png

Gold Problem Solver

Re: Low Upstream Channel Power

You've been given a lot of bad information:

 


@Jireland90 wrote: ... I had a tech come visit and he diagnosed that my modem was the issue.

A bad modem is possible, but unlikely.

 


... the modem manufacturer and they told me that it was a problem with the the upstream power levels. ... it needs at least 45. ...

That's incorrect. Upstream power is typically between 35 and 50 dBmV. The signal level at the modem is not nearly as important as the signal level received by Comcast.

 


... They also said that the service provider would be able to adjust this to the correct level. ... multiple techs and they all have told me there is no way to regulate this.

Comcast's equipment adjusts your modem's transmit power automatically in order to produce the correct signal level ( 0 dBmV ) coming into their system. Their phone and chat reps probably don't know that, but their field service techs really should.

 

Are you using a Wifi or Ethernet connection?

If you want to troubleshoot this yourself, please see Connection Troubleshooting Tips. If you still need help, please provide Information Requested for Connection-Related Posts. If you are using Wifi it's best to switch to an Ethernet cable connection if possible while measuring speed and checking the reliability of your connection to Comcast.

New Poster

Low Upstream Channel Power

I am getting low speeds on my home modem. I had a tech come visit and he diagnosed that my modem was the issue. He plugged in his modem and we were getting 300mbps but with mine only 30 mbps. He recommended I buy a new modem. I contacted the modem manufacturer and they told me that it was a problem with the the upstream power levels. I am only showing around 37 dBmV when the modem manufacturer states it needs at least 45. They also said that the service provider would be able to adjust this to the correct level. Xfinity tells me they are not able to do this so I am just kind of caught in the middle. Was hoping to get some insight into what I can do to remedy this. I have spoken with multiple techs and they all have told me there is no way to regulate this.