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Low signal levels

ddeerrffddeerrff Posts: 154 ✭✭✭✭
in Connectivity Apr 07, 2021

Sorry for the long post, but I wanted to include the whole story.

A few months back, I was having an issue of the internet disconnecting for hours at a time, mostly overnight. I would get a bunch of T3 timeouts, and lose upstream lock. On occasion, I was also getting pixilation on the TV, and the inability to connect with some of the channels (SDV channels?). It seemed to be related to cold temperatures and/or snow.

First truck roll, the tech came in, checked everything in-house, and replaced a couple of splitters 'just because'. Did not resolve the issue. Spectrum did set up a monitor on the connection and confirmed my reports of loss of connectivity. A second truck roll, and the tech basically repeated all the tests the first tech did, and found nothing.

I have a strong background in electronics (35 years RF and Analog engineering for a major medical imaging company) and suggested to the tech that my interpretation of the symptoms I was seeing indicated a problem upstream, and not in the house - and since it seemed to be just me, suggested they check the tap. He told me he needed to find evidence on his own to be able get the right people to even look at it, but that he knew someone in that group and would ask for a favor. THE SECOND TECH DID MENTION THAT MY CABLE RUN TO THE TAP WAS LONG AND THAT THEY USUALLY USED LOWER LOSS COAX FOR THESE LONGER RUNS THAN IS CURRENTLY INSTALLED. Well, the problem suddenly disappeared, but signal levels dropped a bit from what I had been seeing. The modem event log has been clean for a month or so now - great, and correctable and uncorrectable errors have been minimal, but........

I do have a 10 dB bidirectional amp in the basement, and that was tested twice. As it is warming up outside, my signal levels are dropping. I am currently seeing downstream levels approaching -10 dBmV, and upstream levels of very near +50 dBmV. This is with that 10 dB amplifier active.

It sure would be nice if i could get Spectrum to proactively replace that long tap to the house run with the lower loss cable. Any suggestions as to how to approach the issue with support?


  • James_MJames_M Posts: 2,753 ADMIN
    Apr 07, 2021


    Some additional information that may be helpful for your peers includes: what type of modem are you using, when were the last couple visits you mentioned and are you able to post modem logs?

    You mentioned that signal levels are dropping as it warms up. You could have water or damage on the line outside, especially if it was a particularly cold winter. You may need to start with another service call, depending on when you last had a visit.

  • ddeerrffddeerrff Posts: 154 ✭✭✭✭
    Apr 07, 2021

    OK, modem is a Netgear CM600. Not good in keeping records, but I woul say the truck rolls were probably in February - quite a cold month around here. The modem Event Log is currently totally blank, been that way for at least two weeks now. Never did find a good way to post the modem signal levels, but here are some screen snips:

    I've seen the DS a couple dB lower. Keep in mind this is with a 10 dB bidirectional amp inline. Without the amp, I would not get a lock.

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