Regular Visitor
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15 Messages
OFDM PLC Uncorrectables
I have an Arris S34 Modem. I had been getting random disconnects for a while, sometimes multiple a day and sometimes requiring a power cycle on the modem to get connection back. I started doing some investigating and noticed I was getting a lot of uncorrectables on channels 193 and 194. I contacted support and ended up getting set up for a tech visit last Friday. The tech found that there was one cable coming from the node to my utility pole with a splitter on it, with one going to my house and the other to my neighbors. So the tech ran a new line from the node to my utility pole to give me my own dedicated line. The cable from the utility pole to my house was replaced 3 years ago. I had a -40db moca filter at my house enterance so he replaced it with a -70db moca filter. After this it goes to a Antronix CMC2002H-A 2 way splitter which goes to the modem and cable box. The cable from the splitter to the modem and cable box is trueCABLE rg6 quad shield riser 18AWG solid bare copper that was installed last year. After this tech visit channel there seems to not be any uncorrectables on channel 193 but channel 194 is still getting a lot of uncorrectables. Is this normal and what should be expected or is there possibly more issues that I shouldn't have? I have another tech visit scheduled for this Friday.
XfinityAlyssaA
Official Employee
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2.9K Messages
23 hours ago
To confirm, have you checked that all coaxial cable connections are hand-tight and inspected any exposed coaxial cable for damage, such as kinks, sharp bends, cuts, or chew marks? Issues like these can sometimes contribute to signal quality concerns and uncorrectable errors.
That said, based on the symptoms you've described, this is likely something that the technician will need to investigate further during the visit.
I also see that you mentioned having a technician appointment scheduled for Friday. Is that correct?
If so, would it be okay if we checked back in with you after the appointment to see how things went and how your connection is performing afterward? We want to make sure this gets properly resolved and are happy to stick with you throughout the process until everything is working as expected.
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EG
Expert
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120.1K Messages
3 hours ago
@USER89
FWIW. The downstream OFDM channel 194 is borked. The power level is too low / out of spec, as is the SNR. We've seen this here before, where Comcast places an OFDM channel too high in the frequency range near the end of the plant's bandwidth capability. Some of their cable plants and equipment still only extend out to 850 or 1000 MHz operation. At 957 MHz, it may be too close to the roll-off point of the plant's bandwidth capability, which explains the weak power level.
This may need to be escalated to their engineering department for correction. Good luck with it.
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