Intermittent connectivity, unstable connection

[whim0012]

For about a week now, our connection has been unstable.  We have a 200MB account, but every evening our speeds would slow to <1MB, even when wired directly to the modem.  Comcast recommended getting a new modem.  I now have a Netgear CM500 modem as well as a new router.  This has not resolved the problem.  My connection continues to gradually slow and disconnect even when connected directly to the modem, bypassing my router.  While on a Zoom meeting, directly connected to the modem and pulling 150 MB, my connection would occassionally buffer and disconnect.  This wasn't a Zoom issue as connecting to a mobile connection would immediately give better performance, even at a slower speed.

Meanwhile, the modem looks fine to me:

Downstream Bonded Channels

Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables 1 Locked QAM256 17 579000000 Hz -5.1 dBmV 39.5 dB 0 0 2 Locked QAM256 18 585000000 Hz -5.2 dBmV 39.6 dB 0 0 3 Locked QAM256 19 591000000 Hz -4.9 dBmV 39.7 dB 0 0 4 Locked QAM256 20 597000000 Hz -4.7 dBmV 39.8 dB 0 0 5 Locked QAM256 21 603000000 Hz -4.8 dBmV 39.8 dB 0 0 6 Locked QAM256 22 609000000 Hz -4.9 dBmV 39.8 dB 0 0 7 Locked QAM256 23 615000000 Hz -5.1 dBmV 39.7 dB 0 0 8 Locked QAM256 24 621000000 Hz -5.4 dBmV 39.7 dB 0 0 9 Locked QAM256 25 627000000 Hz -5.2 dBmV 39.7 dB 0 0 10 Locked QAM256 26 633000000 Hz -5.2 dBmV 39.7 dB 0 0 11 Locked QAM256 27 639000000 Hz -5.6 dBmV 39.5 dB 0 0 12 Locked QAM256 28 645000000 Hz -5.4 dBmV 39.7 dB 0 0 13 Locked QAM256 29 651000000 Hz -6 dBmV 39.3 dB 0 0 14 Locked QAM256 30 657000000 Hz -5.7 dBmV 39.5 dB 0 0 15 Locked QAM256 31 663000000 Hz -5.8 dBmV 39.5 dB 0 0 16 Locked QAM256 32 669000000 Hz -5.6 dBmV 39.6 dB 0 0

Upstream Bonded Channels

Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power 1 Locked ATDMA 17 5120 Ksym/sec 35600000 Hz 39.8 dBmV 2 Locked ATDMA 18 5120 Ksym/sec 29200000 Hz 39 dBmV 3 Locked ATDMA 19 5120 Ksym/sec 22800000 Hz 38 dBmV 4 Locked ATDMA 20 5120 Ksym/sec 16400000 Hz 36.8 dBmV

After repeated calls to support, Xfinity is 'unable to send a technician'.  So I'm currently faced with either dealing with an unstable connection or cancelling my service.  Before I do, is there anything else I can check or troubleshoot?  Seems I'm on my own.

[EG]

This may not be the root cause of the problem (YMMV) but it should be addressed regardless. 

The downstream power is on the low /weak side and it may be intermittently fluctuating even lower to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

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.

Good luck !

[whim0012]

Thanks for the information.  My downstream power has degraded all day and I no longer have a signal.  My neighbors are now having connectivity issues as well, so I'm led to believe it's an issue at the street.  After repeated calls, xfinity still tells me they can not send a tech to take a look.  Guess it's time to find another ISP...

[EG]

Did any of the tips apply ? It may very well be an outside / neighborhood issue.