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Sat, Sep 26, 2020 7:00 AM

upstream dBmv power levels are a bit low?

Hello everyone, i dont have any problems with my service at all but I logged into my XB7 the other day and compared my upstream power levels to Comcast's recommendations which is from + 38 dBmv to + 48 dBmv.  


My power levels for the 4 upstream channels are attached in screenshot but for those who just wanna take my word for it lol here they are:

32.8 dBmv

33.8 dBmv

32.8 dBmv

33.3 dBmv


So they are a tad bit on the low end and after researching a little bit online about, the consensus seems to be there isn't much on my end that I can do as upstream power level troubleshooting is mostly done on Xfinity's end. Is this true? Or are there some things that I can try on my end to get my upstream power dBmv levels higher and within Xfinity's recommendations?


And like I said, I'm not experiencing any issues at all like dropped connections, slow downloading or uploading times, i'm just curious as to why my power levels are a tad on the low end?


What makes it even more perplexing, is my download power levels are SPOT ON with an average of 0.7 dBmv for ALL channels--which is great because 0.0 dBmv is considered OPTIMAL & nearly perfect for Xfinity.


I appreciate any input oradvice that anyone in this forum; or perhaps a former/current xfinity employee/technician can provide. 


Thank you very much,


- B


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8 m ago

If your Internet service is working well, don't sweat the upstream power numbers.


Comcast's signal specs are the ones posted in the Connection Troubleshooting Tips Forum article, which says the Upstream Power Level at the modem should be between +35 dBmV and +50 dBmV.


The upstream power level is controlled automatically by Comcast's equipment. Although most customers are probably operating in the 35 to 50 range, some work just fine with the modem upstream below 35 dBmV. That's because what's important is not the level at the modem, it's the level (and quality) of the modem's signal as received at Comcast. Comcast reps have no control over this, it's automatic and built into the system.


You can try to get the received-at-Comcast info from a Comcast phone or chat rep if you want. Some know how to read them, but in my experience, many don't.


As mentioned in the troubleshooting guide you'd be asking for the Upstream Signal to Noise Ratio (should be +31dB or more), Upstream Receive Power (should be between -2 dBmV and +2 dBmV), and ICFR (should be 2 dB or less). Comcast's equipment automatically sends commands to the modem to adjust its transmit power so that the signal they receive is as close to 0 dBmV as possible.


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13 Messages

8 m ago

Hi Bruce!

Thanks so much for explaining this to me. I think I get it now. 🙌
I was fairly certain I was just gonna leave well enough alone anyway...but I was curious what the Xfinity forum had to say about it ya know?

Basically if it’s working excellent right now—then there’s no need to “sweat my upstream dBmv level being a lil low” as you put it. Understood.
And once again, thank you kindly.

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