Cable modem losing downstream channels

[JS1983]

Hey,


For years I have had isp issues with my cable internet. New modems, routers, and lines inside and outside house haven't helped. Recent months it has been especially bad.

In the evening, speeds go down to around 5 Mbps or below but are supposed to be 75 mbps. Dozens of tech visits haven't helped until last week. A bucket truck showed up and fixed an issue where my modem was only showing 9 of the usual 16 downstream channels. It stayed showing 16 channels for a few days after the tech left, but tonight it is back down to only 9 channels again and also the really slow speeds. Downstream channel power levels are around 10-11 dbmv. Upstream is around 40-43 on both channels. SNR stays around 40.

Last winter I always lost internet and channels when it got cold out and the power levels would go way out of range, but like I said, the power levels stay pretty steady now whenever I look, so they must have fixed a little of the issue at some point. Weird thing is, my upload usually stays around 7 which I think is around what it should be.

Also, my modem only started losing these 7 channels for about the last month or so. It does not seem to be happening only when it is really cold now though as compared to last winter because right now it is in the upper 60's Fahrenheit, so the temperature doesn't seem to be the problem to me but I could definitely be wrong.


ANY help at all is definitely appreciated.  Thanks

[PineyCreek]

Beyond what you've tried already (my issues with downstream channels were a combination of poor outside line installation and old modem), try removing any splitters you might have in the line to see if that solves the problem (either the cable company's inside their cable box or inside your house on the way to the modem).  I have had old splitters that didn't support a certain level of frequency that interfered with signal.  Also, when you replaced the modem, was it 1-to-1 replacement or was it a different (and hopefully newer/better) model?

 

Also, to your note on weather making a difference: my old outdoor line problem was definitely more apparent in colder and hotter temperatures ('cause thermal expansion/contraction causing slight shifting) with weak/brittle physical connections.

[gibbsy81]

Are any of your neighbors next door to you (assuming they are on the same TAP) seeing any similar issues?

Also which part of the world are you in? Cable/HFC networks around the world can be designed differently specifically around the amount of customers per optical node.

 

[JS1983]

Hey I appreciate the replies.

 

I live in eastern Kentucky.  I have tried a few different lines that come in from outside.  The one I am on now doesn't have any splitters besides the one that is on the outside of my house that splits into two cables that come into the house.  I also tried the other one that splits inside to different tv's but it doesn't help.

 

My current modem is an Arris SB6183.  One Suddenlink tech even tried one of their modems a few months ago, but it didn't solve my speed issues I was having.  But right before this current problem of lost channels, my speeds were decent for a few weeks.

 

As far as I know, my section of the tap only has me and one other property where the house burned down years ago, so no one is on that property anymore.

 

The last tech that finally solved my lost channel issue for a few days said he had to balance a couple of amps I believe.  He has been here several times over the last couple of weeks.  One important point he did make was, he said his previous visit a few days before the last one, he said he adjusted the amps, but after he came back a few days later, he noticed they were off by around 5 db from what he had them set at previously.  So I guess the amps apparently came out of adjustment on their own for some reason.

 

Thanks again for any help

[PineyCreek]

1 hour ago, JS1983 said:

Hey I appreciate the replies.

 

I live in eastern Kentucky.  I have tried a few different lines that come in from outside.  The one I am on now doesn't have any splitters besides the one that is on the outside of my house that splits into two cables that come into the house.  I also tried the other one that splits inside to different tv's but it doesn't help.

 

My current modem is an Arris SB6183.  One Suddenlink tech even tried one of their modems a few months ago, but it didn't solve my speed issues I was having.  But right before this current problem of lost channels, my speeds were decent for a few weeks.

 

As far as I know, my section of the tap only has me and one other property where the house burned down years ago, so no one is on that property anymore.

 

The last tech that finally solved my lost channel issue for a few days said he had to balance a couple of amps I believe.  He has been here several times over the last couple of weeks.  One important point he did make was, he said his previous visit a few days before the last one, he said he adjusted the amps, but after he came back a few days later, he noticed they were off by around 5 db from what he had them set at previously.  So I guess the amps apparently came out of adjustment on their own for some reason.

 

Thanks again for any help

That is rather curious...but the tech likely knows far more than me.

 

Only other thing I can think of is that often they will recommend to test without anything else in the line (hence the splitters comment made earlier) but that can also include things like noise filters and surge protectors (i.e. running the coax through a surge protector that has those connections).

[JS1983]

7 minutes ago, PineyCreek said:

That is rather curious...but the tech likely knows far more than me.

 

Only other thing I can think of is that often they will recommend to test without anything else in the line (hence the splitters comment made earlier) but that can also include things like noise filters and surge protectors (i.e. running the coax through a surge protector that has those connections).

Yeah I am lost on where to go from here.  The coax line I am on right now doesn't go through anything besides that one outside splitter like I said.  Hopefully when he comes back out he can figure something out finally.  Will let you know what happens if I can get them back out tomorrow.  Thanks again for the suggestions and help.

[JS1983]

So bucket trucks came out and have been working on the road I live on.  Several of the guys have told me there is a lot of noise in the lines in the area and a lot of it is coming out of peoples houses.  One guy went outside my house to hook into the line to show me on his meter.  The graph was all over the place and he said it is supposed to be flat.  Just wondering how they will solve this.  Also, is there anything that I can buy that doesn't cost a ton of money to see the noise like he did.  The reason I ask is, if I ever change lines or anything in the future, I would like to know if I create any interference in the process.

Thanks

[Donut417]

4 hours ago, JS1983 said:

Just wondering how they will solve this.

They will find the offending houses and most likely put some kinda of filter on the lines to those homes. 

 

4 hours ago, JS1983 said:

The reason I ask is, if I ever change lines or anything in the future, I would like to know if I create any interference in the process.

Cable systems use the same bands as Broadcast TV, LTE, and some 5G services. The reason cable companies can coexist with these other services is because it travels along a cable. But damaged cables, Damaged connectors, loose connectors and bad equipment can all cause interference on the line. 

[JS1983]

So another tech came out and tried one of their modems.  When he tried his, it connected quick and with 24 channels.  He said my area only uses 24.  While he was here, my modem was taking a few minutes to lock in and it was still only getting 9 of its 16 channels.

 

My question now is, he says he thinks it is the modem, but every time they come out and balance the amps or anything, I usually get my missing channels back for a day or two.  Even a few minutes before he got to my house yesterday, my TV and internet both went out for a few minutes.  When they came back on I had my missing channels back again until he got here and restarted my modem.  He said the reason the service went out for a few minutes was because he was down the road I think at the node doing a speed test, I guess to see if the main lines are up to par or whatever.  He said he didn't fix anything though so he didn't know how I got my channels back for a few minutes.  So if my modem is bad, how do I get missing modem channels back when they mess with the amps and everything.  Like I said though, while he was here, his modem was locking in on all channels when mine wouldn't.

 

I have been through several modems over the years for low speed issues that were never resolved which is why I am hesitant to buy yet another one.

 

Thanks for any suggestions