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Comcast Internet Intermittent Connectivity Issues

Netguy333
Aspirant

Comcast Internet Intermittent Connectivity Issues

Hoping someone can help with my intermitent connectivity issues with Comcast / XFINITY.  I have called Comcast numerous times over the past three months, and each time they have me unplug power to my Netgear CM500V and my home Wifi Router (Synology RT2600AC), do a remote check of the signal, etc., but are never able to fix it for me.  They said they would send a tech out to check the lines outside the house twice but they never showed.  I only have one splitter outside the house which splits the main line into one that goes to my cable modem and one that goes directly to my Comcast TV Box.  This all started happening a few months ago, and I have had this cable modem installed for the last 7 months (which I added a Voice line to my Cable service, thus the need to get the CM500V with a phone hookup).  The splitter outside is an Extreme BDS102H which may be the original splitter from when we moved to this house 14 years ago, so I have ordered a new one from Amazon to install this weekend in hopes that is the issue.

The main issue I am having is internet connection drops that occur when I am on Skype/Zoom/Webex, or when I am playing online games that also have VOIP functionality.  I also notice on my iPhone that internet connectivity will drop while watching Youtube at around 12:04 am (this happens often, usually around 12:04 am).  I have confirmed that my Wifi router only reboots itself automatically on Sundays at 4am, so that can't be the issue.  Kind of at my wits end here and hoping someone in this forum might have some suggestions for me to try.  Atrtached is a screenshot from the management interface of the Cable Modem.

 

 

Model: CM500V|Cable Modem for Internet & Voice–DOCSIS 3.0
Message 1 of 10
FURRYe38
Guru

Re: Comcast Internet Intermittent Connectivity Issues

What happes if you remove this splitter and directly connect the modem cable here. You may need a barrel conenctor to do this. 

It's recommended to have a direct RG6 coax cable line from the ISP service box to the modem and not use any kind of splitter. 

You can try and get a newer good quality splitter if needed, however may not change anything. 

 

Need to use good quality RG6 coax cabling as well. 

 

Need to get a tech onsite and have a good look at this as well. 

My Setup ISP SparkLight | Internet Cable 1000↓/50↑ CAX80 Modem Mode |  Wifi Router MK83+ (Router Mode) | and RBK853 (Router Mode) | Switches NG GS105/8, GS308v3, GS110MX and XS505M | Additional NG HW: C7800/CAX80/CM1100/CM1200/CM2000, Orbi: CBK40, CBK752, RBK50, RBK853, RBK752, RBK953, SXK30 | NightHawk: MK63, MR6150, R7000, R7800, R7960P, R8000, R8500, R9000, RAXE500, RAX50, XR450, XR1000, EX7500/EX7700

Message 2 of 10
Netguy333
Aspirant

Re: Comcast Internet Intermittent Connectivity Issues

Thanks for the suggestions.  We have about a 50 foot run from the juntion box in the yard by the street where Comcast ran a single coax line up to the house.  That is where they split it before it goes into the house (see attached photo).  We have also been having reception problems with our Cable tv recently, so either the signal from Comcast isn't sufficient (which their phone support team claims is not the case, they said it was a faulty TV box that we need to bring in and swap), or the splitter is going bad (which I should know for sure by tomorrow when I get the new one).  I could try disconnecting the splitter and put a barrel connector in to have a single line going to my cable modem.  If the new splitter doesn't fix it, I'll try that to see if that helps (thinking about cancelling my TV subscription anyways, so this may be a valid reason to do so since Comcast isn't willing to come out to my house to check on the lines).  I'll keep you posted on my progress.  I really don't want to have to switch to Verizon FIOS, but I may not have a choice if I can't resolve this connectivity issue.  Any chance it could be the Cable modem itself (CM500V)?

Message 3 of 10
FURRYe38
Guru

Re: Comcast Internet Intermittent Connectivity Issues

Make sure the signal on the line is good, then move to check out the modem. Modems depend on having good signal to process.

My Setup ISP SparkLight | Internet Cable 1000↓/50↑ CAX80 Modem Mode |  Wifi Router MK83+ (Router Mode) | and RBK853 (Router Mode) | Switches NG GS105/8, GS308v3, GS110MX and XS505M | Additional NG HW: C7800/CAX80/CM1100/CM1200/CM2000, Orbi: CBK40, CBK752, RBK50, RBK853, RBK752, RBK953, SXK30 | NightHawk: MK63, MR6150, R7000, R7800, R7960P, R8000, R8500, R9000, RAXE500, RAX50, XR450, XR1000, EX7500/EX7700

Message 4 of 10
jimbo57
Aspirant

Re: Comcast Internet Intermittent Connectivity Issues

I have a similar problem, my modem will work perfectly till 9:30 AM Eastern Time.  It will act irradically till around noon, and then flaulessly till 9:30 AM the next morning.  I have documented this.  Like the original poster, Comcast has consistantly refused to check out the house cables, claiming Covid19 concerns, even working outside the house.  

Model: CM500|16x4 DOCSIS 3.0 Cable Modem
Message 5 of 10
FURRYe38
Guru

Re: Comcast Internet Intermittent Connectivity Issues

You'll have to keep checking with the ISP about this. They need to check there services up to the modem. 

My Setup ISP SparkLight | Internet Cable 1000↓/50↑ CAX80 Modem Mode |  Wifi Router MK83+ (Router Mode) | and RBK853 (Router Mode) | Switches NG GS105/8, GS308v3, GS110MX and XS505M | Additional NG HW: C7800/CAX80/CM1100/CM1200/CM2000, Orbi: CBK40, CBK752, RBK50, RBK853, RBK752, RBK953, SXK30 | NightHawk: MK63, MR6150, R7000, R7800, R7960P, R8000, R8500, R9000, RAXE500, RAX50, XR450, XR1000, EX7500/EX7700

Message 6 of 10
Netguy333
Aspirant

Re: Comcast Internet Intermittent Connectivity Issues

So I go the new splitter (Extreme BDS102H, same as what was installed by Comcast) from Amazon yesterday, and also found another brand splitter I had laying around in my basement (Antronix CMC2002H-A).  I compiled the power and SNR changes into a PDF (attached).  I have decided to try the Antronix splitter for now to see if that makes a difference, even though the SNR got a little worse than using the comcast provided brand (but power did increase).  I really don't suspect this is going to fix my issue, but will know by the end of this week and I'll keep you posted.

 

Summary:

  • Replacing original splitter (Extreme) with identical new one resulted in an increase in power, but a decrease in SNR for downstream (no big change in upstream).
  • Replacing original splitter with a different brand (Antronix) resulted in an increase in power, but a decrease in SNR for downstream (no big change in upstream).
  • Removing splitter resulted in a big increase in power, but a decrease in SNR for downstream (with a decrease in power for upstream).

If anyone has any suggestions on how to get proper support from Comcast during this pandemic, please let me know.  Thanks!

 

Message 7 of 10
Netguy333
Aspirant

Re: Comcast Internet Intermittent Connectivity Issues

Still experiencing internet connection drops on occasion, and some channels on our TV are still pixelated.  Oh well.  Will try to get Comcast to come out some day once this pandemic is over.

Message 8 of 10
FURRYe38
Guru

Re: Comcast Internet Intermittent Connectivity Issues

Ya, the ISP tech needs to inspect the line and single from there service box up to the modem.

 

Good Luck. 

My Setup ISP SparkLight | Internet Cable 1000↓/50↑ CAX80 Modem Mode |  Wifi Router MK83+ (Router Mode) | and RBK853 (Router Mode) | Switches NG GS105/8, GS308v3, GS110MX and XS505M | Additional NG HW: C7800/CAX80/CM1100/CM1200/CM2000, Orbi: CBK40, CBK752, RBK50, RBK853, RBK752, RBK953, SXK30 | NightHawk: MK63, MR6150, R7000, R7800, R7960P, R8000, R8500, R9000, RAXE500, RAX50, XR450, XR1000, EX7500/EX7700

Message 9 of 10
UserSteve
Aspirant

Re: Comcast Internet Intermittent Connectivity Issues

Just wanted to let you know that you are not alone with this issue. For the past 3 months I've lost internet almost daily between 5:00PM and 7:00PM. Throughout the 3 months, it's gone from a daily occurrance to a once/twice a week issue.

 

I've had a Comcast tech come out, check all the wires, splitters, signals, etc. They claim there's nothing wrong on their end. Starting to lose hope that it will get resolved.

 

EDIT: A reboot of my gateway (C6250 running firmware V1.02.01) will "fix" the issue. However, somehow, powercycling the device has caused it to lose its settings twice now. So I have to reconfigure my entire network aftewards.

Message 10 of 10
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