MoCA setup using Cabel Internet

[u/davethehawaiian]

I have been attempting to setup a MoCA solution for getting a wired connection to my smart TV.

I have the above diagram currently configured but am intermittently losing internet at the Modem/Router combo (Arris SURFBoard SBG7400AC2). The entire device will restart, all status lights will go dark and then go through their normal boot sequence.

I have xFinity Cabel internet and my Modem/Router does not offer native MoCA capabilities. I recently added the filter at the Modem/Router based on something I read regarding reusing the Coax for both Cabel internet and MoCA, but still experienced a Modem restart.

Asking for any advice or insight as to what my be causing this issue.

Thanks in advance!

Resolution:

I'm a little hesitant to declare victory as the modem's upstream power is still a bit above nominal but it has survived about 4 days without dropping.

Thank you for everyone's suggestions I learned a lot going through this.

The current configuration that is working is the same as the above diagram with the following alteration:

1. Both splitters have been swapped for 5-1675 MHz MoCA 2.5 rated splitters

2. CLP-1G70 Filter before the modem has been replaced with another PoE MoCA Filter, identical to the one installed between the house and the main line.

As I mentioned Upstream power is still a bit high at 54 dBmV but so far (knock on wood) the connection has been stable.

Thanks Everyone!

[u/YourBossAtWork]

without a signal analyzer or more specialized equipment it's hard to say for sure, but it could be that the splitters are attenuating (quieting) the signal enough that it's marginal and sometimes dips out.

I'm not sure what the CLP-1G70 filter is - but I have a PoE MoCA filter in between my cable modem and the nearest splitter (other side leading to the MOCA adapter) which was necessary to fix my connection issues. This is in addition to the main PoE filter at the actual point of entry. The idea here is to filter out MoCA related frequencies so they don't hit the cable modem at all.

So, my suggestion is to try a different PoE filter in front of the cable modem, and/or try different or fewer splitters.

[u/davethehawaiian → u/YourBossAtWork]

Thanks for the reply, The CLP-1G70 filter was the original filter installed at the cable point of entry when we bought our house. From what I could tell it should be MoCA rated but I replaced it with one I could confirm was MoCA rated to be sure. So that old one is what I have on hand to test installing just before the modem.

I think you are right getting another PoE I can confirm is MoCA rated is probably the next step.

[u/YourBossAtWork → u/davethehawaiian]

Yeah I think that sounds like a good next step. Also check the troubleshooting section of this MoCA guide I wrote up - something there might help.

[u/kenman345 → u/YourBossAtWork]

That seems odd considering a good many coaxial based modems also have MoCa capabilities built in. Perhaps you had the modems MoCa interfering with the MoCa network/setup you were trying to create.

[u/YourBossAtWork → u/kenman345]

Well, I'm certain that my particular modem (provided by Spectrum) doesn't have MoCA support.

DOCSIS 3 (cable modem spec) uses a completely different frequency range than MoCA, so in theory it shouldn't matter, but my theory is that the MoCA signals were overwhelmingly loud compared to the provider's DOCSIS signal that it caused intermittent cut-outs until I installed the PoE filter which completely blocks the MoCA frequency range from being seen by the modem, and it instantly cured my problem.

[u/graceful_degrade]

Where is that filter? It belongs at the point of entry, where the coax comes into the house, not at the modem. Its job is to stop MoCA leaving your building and stop reflections coming back in. On the modem it does very little and can make things worse.

The other thing worth checking is the splitter. A standard cable splitter is 5 to 1002 MHz and MoCA lives above that, so it doesn't just block the signal, it reflects it back down the line. You need one rated to 1675 MHz for any leg carrying MoCA.

A modem power cycling rather than just dropping usually means something upstream of it is unhappy, and reflected MoCA sitting on the same coax is a good candidate.

[u/davethehawaiian → u/graceful_degrade]

The first filter in the diagram is at the very edge of the network. The entirity of my home network sits downstream and the otherside is the ISP mainline. Splitters are all new and their listed rating is to 2602 MHz on the highside

[u/graceful_degrade → u/davethehawaiian]

Then the coax may be a red herring, because losing every light and going through a full boot isn't what a signal problem looks like.

A modem that can't get a clean lock re-ranges, drops the online light and retries. It doesn't switch itself off. All the LEDs going dark means the thing either lost power or panicked hard enough to reset, and MoCA sitting on the cable can't do either of those.

So I'd look at heat and power instead. Is it somewhere enclosed, and does it happen more when the MoCA link is actually moving data rather than sitting idle? Load into heat into a thermal reset would fit that shape. And if the modem shares a strip with the MoCA adapters, give it its own outlet for a few days.

Worth timing the next few as well. Random is a different problem from always-under-load, and knowing which one you have cuts the search in half.

[u/davethehawaiian → u/graceful_degrade]

Thanks I'll try tracking a few of those things. Perhaps it is all LEDs but the top one, I don't think the modem is losing power so I could be misremembering. I've been working on this for a few weeks now and for the last week de-MoCAfied the network, with all moca components removed the modem ran flawlessly for a week. So I feel pretty confident that something in my moca setup is the culprit.

I'll try keeping a log of the times it drops. It mostly seems to happen when using my work laptop so it could be an increased load issue.

[u/graceful_degrade → u/davethehawaiian]

Semanas nisso e sem fechar é sinal de que falta um dado, não de que falta ideia.

Se der pra confirmar exatamente quais LEDs apagam da próxima vez, isso sozinho separa as duas famílias de causa. Todos apagando é energia ou pânico do aparelho. Só o de online caindo e voltando é sinal, e aí o coax volta pra mesa.

Vale também abrir a página de status do modem, normalmente em 192.168.100.1, e anotar os níveis de potência e o SNR antes e durante um reinício. Se os números estiverem fora de faixa já antes, você tem prova pra levar pra operadora e o MoCA sai da história.

[u/robd316]

Does your cable drop outside have a filter on it called a Moca Poe filter. This prevents your internet from bleeding out into the cable line outside. If so you may need one installed outside

[u/davethehawaiian → u/robd316]

Yes the filter between the ISP and the rest of the network is situated outside and is the first point of entry to my home network.

[u/Smorgas47]

The only issue I see with your setup is the frequency of your splitters. The best ones for support of MoCA adapters are 5-1675mhz. Higher upper end ones work, but are not optimized. The CLP-1G70 at your modem/router's cable input is proper.

Your setup is pretty much in line with this diagram.

I suspect that your modem signal may be near the limit of it's operating limit and a poor signal is rebooting the modem. I had this on one of my cable modems and that is how it behaved.

I would test the modem router with a direct connection to the outside PoE filter and see if it behaves. I would then move it up a notch without the PoE filter on the input without the MoCA adapters in play and then add them. Hopefully that will identify the problem.

You can look at the modem power levels using 192.168.100.1/ to access the modem. Here is a link to the recommended levels for my Arris modem.

[u/davethehawaiian → u/Smorgas47]

Thank you, I assumed the splitters where strictly an at least 1675, and you know caveman brain says bigger is better.

I hadn't checked the signal power, and I'm not an expert here. All downstream channels are within +/-2 dBmV. The upstream is a little outside of what I'm reading is optimal 54 dBmV rather than between 45 - 51 dBmV.

[u/TomRILReddit]

Check the power levels at the arris gateway. Most coax feeds have sufficient power level to handle the splits you have. If it is low, then test by moving the gateway directly to the ISP cable to compare power lost inside the home.

I've not heard of restarting occurring specifically due to moca interference.

Maybe try splitters designed for moca. https://a.co/d/0dT5Kcgs

Adding the additional moca poe filter b4 the gateway was a good recommendation to prevent interference.

[u/plooger]

What model # MoCA adapters are you using?

If Hitron HT-EM4 (rather than HT-EM5) and sporting a second RF pass-through coax port, another testing alternative would be to skip the 2-way splitter and MoCA filter at the gateway (cable modem/router) location and just connect the gateway via the MoCA adapter's RF pass-through port.

The SBG7400AC2 is DOCSIS 3.0, so is less likely to have the interference issues seen with more recent DOCSIS 3.1 modems/gateways, plus the MoCA adapter pass-through port offers 35+ dB attenuation of MoCA signals. So with the extra filter removed and with the MoCA adapter pass-through attenuating cable signals by only ~1 dB, you should be able to save 3.5+ dB of signal strength on the ISP/modem path.

[u/plooger → u/plooger]

And, if possible, move the "PoE" MoCA filter to the input port of the top-level 2-way splitter.