Hello All. I have a Netgear CM1150V which has been working amazingly well for months. Now recently over the past 3 weeks or more, I've been having many issues with download speeds. The upload speeds seem unaffected. I will even have some web page timeouts while simultaneously showing theat the cable connection is "good" in the modems admin panel.
Resetting the modem seems to do the trick from time to time, but then inevitably the problems resume. When I call in they tell me to call the manufacturer (Netgear) to resolve the issue, but I know the problem lies outside of my home. Netgear finds nothing wrong with the modem.
A newer Intel i7 desktop build with Win10 hardwired
Netgear CM1150v modem
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Hi, I'm just another user, and seeingthe same problem you are. One thing I've learned is the upstream power level should be less than 50 dBv. I beleive a good level would be much lower like 35. Yours are near 50, and mine are too. I think this means there is too much signal loss upstream from your modem to comcast. Other posters have reported similar, and a possible correlation with hot weather: perhaps comcast equipement along the cable line has more loss (or less gain) at higher temps. A few years ago we went through this and only got it solved when they sent an engineer (not just a tech) out to troubleshoot. He ended up adjusting line amps (I think) out on the street somewhere and that solved it.
The upstream power is on the high side and it may be intermittently fluctuating even higher 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.
I have one splitter inside the house in my data closet. That's it. And I just replaced a few days ago it to make sure it wasn't the problem with the following. I have one coax going to the modem, one to the DVR, and another from the pole. No extra ports on the splitter.
How do I get a hold of a technician?
First Ditch that splitter and see. It is engineered for satellite systems, not coax cable systems. It can actually make the connection quality worse !
Here are some quality brand splitters that Comcast actually uses in different market areas;
Antronix CMC2002H 2-Way Splitter: http://www.amazon.com/Antronix-CMC2002H-2-Way-Splitter/dp/B001E4OH1E
Regal 2 WAY 1 GHZ Splitter: http://www.amazon.com/DIG702867-Regal-WAY-GHZ-SPLITTER/dp/B0018BQMUM/ref=sr_1_2?s=electronics&ie=UTF...
Extreme Broadband BDS102H 2-Way Digital Coax Splitter: http://www.amazon.com/EXTREME-DIGITAL-PERFORMANCE-CABLE-SPLITTER/dp/B007YV0UQW
Holland 2-way horizontal splitter 5-1000 MHz with ground.http://www.3starinc.com/holland_2-way_horizontal_splitter_5-1000_mhz-w-ground.html
Sv-2g 2-way Splitter 5-1000mhz: http://www.amazon.com/Sv-2g-2-way-Splitter-5-1000mhz-Sv2g/dp/B003TH36CK
It started before the splitter. Same issues with two different splitters. One being the original from Comcast. I'll buy one of the ones you suggested, but I'm pretty sure the result will be the same...
While I sincerely appreciate your input. You don't seem to be willing to answer the million-dollar question...
Uh. I did say first. And I did give you troubleshooting tips. So I don't what you mean by that comment. I'm not a magician that can automatically and instantly solve every issue remotely, sorry.
Hi again, it's your fellow comcast victim/customer. I made some progress today and thought it might help. We had a 4 way splitter, provided by comcast, but only using three outputs. I also have a collection of splitters from over the years, including a couple 2 way splitters that were from comcast. So I removed the 4 way, installed a 2 way, with one output going to cable modem. The other output of 1st splitter goes to the input of the 2nd spllitter, and those two outputs go to two TV cable boxes. This seems to have helped. Now the cable modem sees 1/2 the signal, versus 1/4 before. The downstream signal strength was higher and the upstream signal waslower, which is a good thing, means less power is required to talk back to comcast headend. The internet works better so far, but more time will tell. But then we noticed some TV channels were breaking up, on both TVs. That's a puzzle, since both TVs should be getting 1/4 the signal, same as before. So I carefully examined all the connectors, and found some crud on some of them, especially the comcast line from the pole. I cleaned all of these and put everything back together. The Tv channels all work again, the cable modem signals are even better than before (downstream gained about 3 dB, and upstream dropped about 3 dB, both good) and so I think we've got more "headroom" then before. Final note, as a troubleshooting step, I had removed all splitters and connected cable modem direct to comcast line from pole. So I suggest you check your connectors, make sure the white foam between the center lead and the gorund shield is nice and clean. I used a q-tip and alcohol, and now I'm getting better signals now with the splitter and cleaned up connections, than I was getting with a direct connection before cleaning. Good luck!
Thank you. I'll give the "straight from the pole" trick a try to see what happens... Thanks!
PS "Fellow Comcast Victim" 🤣