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krisok77's profile

New Member


1 Message

Fri, Dec 11, 2020 7:00 PM

Low Upstream power after local outage

I am getting low upstream power on my modem connection since the beginning of the week when there was an outage in my area. I keep getting between 10 to 20 percent packet loss and it is impacting my business. I have contacted technical support and was told I would get a call back from a local tech. I did not get any calls and the issue is still ongoing.  Any help would be appreciated. I was by tech support that my power lever should be higher than 45dBmV. See below for my current levels.

Upstream Bonded Channels

ChannelChannel IDLock StatusUS Channel TypeFrequencyWidthPower
13LockedSC-QAM Upstream22800000 Hz6400000 Hz38.0 dBmV
21LockedSC-QAM Upstream35600000 Hz6400000 Hz37.0 dBmV
32LockedSC-QAM Upstream29200000 Hz6400000 Hz37.0 dBmV
44LockedSC-QAM Upstream16400000 Hz6400000 Hz38.0 dBmV
55LockedSC-QAM Upstream39600000 Hz1600000 Hz37.0 dBmV


Official Employee


412 Messages

2 y ago

Hello @krisok77, thanks for reaching out about the connection issues. We definitely understand how vital it is for your business to have a solid and steady connection! We would be glad to look into this for you. To get started can you please send us a private message including your name, the business name, the complete service address (including city, state, ZIP, suite number, etc), and the phone or account number?

To send a Private Message please click on my handle, Comcast_Gina, and "send a message" 🙂 

New problem solver


70 Messages

2 y ago

Keep calling Comcast. I find local techs often don't respond unless they get a couple notices.


But... Low upstream power is good. Low downstream power is bad.


Upstream power is the power used by your modem to send data. The cable will increase the upstream power if your connection is not very good, and more power is required to complete the connection. 37-55 dbmV are usually "good" (but may depend on the modem). So looks like that part is alright for you.


The downstream power is the strength of the signal you are receiving. Depends a bit on your modem what is "good". But +/- 8dB is good (+/- 15dB is normal for some modems). A signal that is too strong can cause problems as well but is easily fixed with a splitter or an attenuator. 


The most important number is usually signal to noise (SNR) which should be > 30 dB.


Just as an example the numbers from my modem (Comcast provided "business gateway") which currently works well:

SNR: 40dB
Upstream Power Level: 39-39 dBmV
Downstream Power Level: 10 dBmV


See if your modem has a display that shows how many errors you have. There may be some, but the number should be small. For example, in my case, I got something like 4 Billion total "codewords", but only 10 errors and they are labeled as "Correctable".