Modem keeps restarting

Hikaru12 · July 12, 2017

I've checked the power levels and the upstream seems to be too high. It fluctuates as right now it's steady at 44 but sometimes it goes as high up as 50 or so so I have a strong feeling that's the issue. I also notice that, that's where it gets stuck when the modem reboots as the downstream works just fine and is within spec. It's a DOCSIS 3.0 Motorola SB6121 cable modem.

I took a look outside at my cable box. It's using a 1000MHZ 3 way splitter with -5.5DB loss at each end. I'm wondering if upgrading this splitter outside to a higher MHZ band would help the upstream power level? I've thought about buying a coaxial amplifier but I heard that introduces unwanted noise which can affect my downstream power levels too. What are my options?

For the record, my log states most of my issues are T3 related. This rebooting happens every few hours to every day or so.

Donut417 · July 12, 2017

55 minutes ago, Hikaru12 said:

I've checked the power levels and the upstream seems to be too high. It fluctuates as right now it's steady at 44 but sometimes it goes as high up as 50 or so so I have a strong feeling that's the issue. I also notice that, that's where it gets stuck when the modem reboots as the downstream works just fine and is within spec. It's a DOCSIS 3.0 Motorola SB6121 cable modem.

I took a look outside at my cable box. It's using a 1000MHZ 3 way splitter with -5.5DB loss at each end. I'm wondering if upgrading this splitter outside to a higher MHZ band would help the upstream power level? I've thought about buying a coaxial amplifier but I heard that introduces unwanted noise which can affect my downstream power levels too. What are my options?

For the record, my log states most of my issues are T3 related. This rebooting happens every few hours to every day or so.

No, because all cable and internet service is run under 1Ghz with the exception of Docsis 3.1 service.

Check all of your connections to make sure they are tight. Make sure none of your connectors are corroded. What you can try to do is use two way splitters instead. Two way splitters will have less loss, 3.5 Db compared to 5. Your power levels can go up and down by 3 db during the day. Heat causes the issues. Going from 44 to 50 sounds like a big issue. You might need them to come out and check your line or the drop your connected to.

Hikaru12 · July 12, 2017

1 hour ago, Donut417 said:

No, because all cable and internet service is run under 1Ghz with the exception of Docsis 3.1 service.

Check all of your connections to make sure they are tight. Make sure none of your connectors are corroded. What you can try to do is use two way splitters instead. Two way splitters will have less loss, 3.5 Db compared to 5. Your power levels can go up and down by 3 db during the day. Heat causes the issues. Going from 44 to 50 sounds like a big issue. You might need them to come out and check your line or the drop your connected to.

I found -this- signal booster which is bidirectional which I've heard some good things from. I might use that with your suggestion of a 2 way splitter. I've been planning on switching the home phone which goes from POTS to Coaxial over a RJ11 adapter modem to Google Voice w/ a Odaheim box. I want to get this sorted out now before I upgrade to a Docsis 3.1 modem w/ a 200Mbps plan (right now I'm running a 25mbps which is starting to not cut it anymore) because I've heard Docsis 3.1 specs are even more tighter and stringent.

Donut417 · July 12, 2017

1 hour ago, Hikaru12 said:

I found -this- signal booster which is bidirectional which I've heard some good things from. I might use that with your suggestion of a 2 way splitter. I've been planning on switching the home phone which goes from POTS to Coaxial over a RJ11 adapter modem to Google Voice w/ a Odaheim box. I want to get this sorted out now before I upgrade to a Docsis 3.1 modem w/ a 200Mbps plan (right now I'm running a 25mbps which is starting to not cut it anymore) because I've heard Docsis 3.1 specs are even more tighter and stringent.

Your better off contacting your provider. They can trace where the issue is. We had higher power on our upstream for the longest time. Our neighbor called about here TV kept cutting out. Ended up the drop we were on was bad. Now power levels on upstream are low to mid 40s. It sounds like you have two modems connected to your service as well, one for internet and one for voice. I would say get rid of the phone service. Buy a better modem and check your lines between the line from the pole and your modem. Make sure the line is not bad or any of the connectors are not bad.

Also, if your willing, you can take your modem outside to where the line comes in to your house, unhook the cable before the grounding block and plug it in to the modem. Get signal reading from there. Thats a good way to tell if the issue is on their end or your end. Because if the signal is shit coming from the pole, then its not an issue on your end.

Hikaru12 · July 13, 2017

21 hours ago, Donut417 said:

Your better off contacting your provider. They can trace where the issue is. We had higher power on our upstream for the longest time. Our neighbor called about here TV kept cutting out. Ended up the drop we were on was bad. Now power levels on upstream are low to mid 40s. It sounds like you have two modems connected to your service as well, one for internet and one for voice. I would say get rid of the phone service. Buy a better modem and check your lines between the line from the pole and your modem. Make sure the line is not bad or any of the connectors are not bad.

Also, if your willing, you can take your modem outside to where the line comes in to your house, unhook the cable before the grounding block and plug it in to the modem. Get signal reading from there. Thats a good way to tell if the issue is on their end or your end. Because if the signal is shit coming from the pole, then its not an issue on your end.

I've actually connected the modem directly to the wall instead of how I had it (a power strip connected to another power strip) and it seems to be holding the upstream level at 43dbV so we'll see if it continues. This may have fixed the issue.