Visitor
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2 Messages
Very slow internet, and very low downstream power levels. (dBmV)
Hello and good day,
I've had some connection issues occurring for the past few weeks, and although they started off as an intermittent problem, they have now become constant. My download speeds always used to be at, or slightly over, 1200Mbps. Recently, however, they began to test under 20Mbps consistently, and sometimes drop to as little as 2-3Mbps. The numbers on my upstream have remained right around 40Mbps the whole time. Also, the internet will completely cut out once every couple of days which will leave a flashing red light on the modem that requires a hard reboot to resolve.
To troubleshoot, I have replaced the coaxial cable connecting the modem to the wall outlet, removed and tested the wall jack with a multimeter to verify it's functionality, and tested the speeds on a desktop PC via both ethernet and WiFi to eliminate any variables. Both WiFi and ethernet connections provide the same test results.
Looking at my modem diagnostics, my upstream power is fine at 45.0 dBmV, but my downstream power levels seem pretty low. They clock in from -15.1 dBmV down to -20.3 dBmV. My SNR on the primary channel has dropped to 32.1 dB, and the modulation shows as "Unknown" rather than 256 QAM. I can provide screenshots of these if necessary.
I see no need to have a technician visit to solve this problem if it can just be resolved by the right information getting to the right people. Is there any way Xfinity support can investigate the local node and potentially increase the downstream power being sent to my tap? Any remote diagnostics or adjustments you could perform would be greatly appreciated.
Thank you and have a great day!
EG
Expert
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116.5K Messages
13 hours ago
Yep. The downstream power and the SNR's are too low / out of spec. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.
In an effort to try to obtain better connectivity / more wiggle room, check to see if there are any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/reconfigured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage from Home Depot, Target, Wal-Mart, etc. Splitters should be swapped with known to be good / new ones to test.
Also, check the coax cable for any damage such as cuts, nicks, abrasions, kinks, sharp bends, or animal chews.
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.
Good luck with it !
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XfinityBrianH
Official Employee
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2.1K Messages
13 hours ago
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