I have a Motorola MB8600. I'm subscribed to Xfinity for 500Mbps download speeds and 10Mbps upload. Each day, for the past three weeks, my internet download speeds have dropped to <1Mbps. Upload speeds are stable. The only way to fix download speed is to reboot the modem. Post-reboot, download speeds return for some undertermined amount of time (1hr - 1 day) before I have to reboot again and repeat the process. Xfinity has been of no help to me in solving this issue and basically pushed me off to contact Motorola directly, which I've done. Motorola says the modem is operating properly, so now I'm at a loss about the best way to proceed. I have 32 downstream channels (QAM256) with a Pwr (dBmV) range of -13.4 to -20.3 and SNR (db) range of 32.4 to 38. Question is, is this range of noise on the Xfinity line acceptable, and if not, how do I get Comcast to help me!
The downstream power is too low / out of spec. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, and latency problems.
In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test
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.
Thank you .@ComcastAndrew but without actually seeing all of the actual stats, why would they not be reporting stuff that is that far out of range ?