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Intermittent connectivity, unstable connection

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Intermittent connectivity, unstable connection

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
ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
1LockedQAM25617579000000 Hz-5.1 dBmV39.5 dB00
2LockedQAM25618585000000 Hz-5.2 dBmV39.6 dB00
3LockedQAM25619591000000 Hz-4.9 dBmV39.7 dB00
4LockedQAM25620597000000 Hz-4.7 dBmV39.8 dB00
5LockedQAM25621603000000 Hz-4.8 dBmV39.8 dB00
6LockedQAM25622609000000 Hz-4.9 dBmV39.8 dB00
7LockedQAM25623615000000 Hz-5.1 dBmV39.7 dB00
8LockedQAM25624621000000 Hz-5.4 dBmV39.7 dB00
9LockedQAM25625627000000 Hz-5.2 dBmV39.7 dB00
10LockedQAM25626633000000 Hz-5.2 dBmV39.7 dB00
11LockedQAM25627639000000 Hz-5.6 dBmV39.5 dB00
12LockedQAM25628645000000 Hz-5.4 dBmV39.7 dB00
13LockedQAM25629651000000 Hz-6 dBmV39.3 dB00
14LockedQAM25630657000000 Hz-5.7 dBmV39.5 dB00
15LockedQAM25631663000000 Hz-5.8 dBmV39.5 dB00
16LockedQAM25632669000000 Hz-5.6 dBmV39.6 dB00

 

 

 

Upstream Bonded Channels
ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA175120 Ksym/sec35600000 Hz39.8 dBmV
2LockedATDMA185120 Ksym/sec29200000 Hz39 dBmV
3LockedATDMA195120 Ksym/sec22800000 Hz38 dBmV
4LockedATDMA205120 Ksym/sec16400000 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.

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Expert

Re: Intermittent connectivity, unstable connection

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 !



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I am a Customer Expert volunteering my time to help other customers here in the Forums.
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New Poster

Re: Intermittent connectivity, unstable connection

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...

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Expert

Re: Intermittent connectivity, unstable connection

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



I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!