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Morac
Cat god

join:2001-08-30
Riverside, NJ
kudos:1
Reviews:
·Comcast
reply to Streetlight

Re: [Connectivity] Modem keeps losing upstream channel bonding

I'm beginning to wonder if this may be at least partially caused by something on my end.

I have a pair of Netgear MoCa bridges: one between my modem and the wall outlet and the other off a splitter near my TV.

Today my upstream signals took a major dive and my modem lost sync and got stuck trying to find an upstream channel. At the same time my TV signals crapped out and I had a SNR of 29 on one my lower frequency channels (not enough to lose picture, but I was getting a lot of corrected errors).

I called into Comcast and they told me all my neighbors were online so I tried disconnecting my modem and hooking up an old DOCSIS 2.0 modem. That wouldn't lock either. I then bypassed my Netgear MoCA bridge and the modem locked and actually got a 44 dB upstream power level. I then placed the Netgear MoCA bridge back in and the modem still locked with the upstream power level about 45 dB. I checked my TV downstairs and the signal levels looked good there too after this.

So it looked like the MoCA bridge was somehow corrupting the upstream and low frequency signals a lot and the higher frequencies a little, but that makes no sense since the MoCA bridge is supposed to operate at frequencies greater than 1 GHz and has worked fine for a few years now. What's odd is that on October 9th, when I first started having problems, the Comcast tech measured the signals before and after the MoCA bridge and they were basically the same. Also I don't know why a MoCA bridge upstairs would cause problem with the TV downstairs

I suppose that it could be a coincidence that the signals got better when I disconnected and reconnected the MoCA bridge, as the time it got better was around the same time it got better yesterday, but that seems suspect. I also have 3 other MoCA devices, none of which I disconnected to get things working, though the one I disconnected is the "Master/Controller".

Currently my modem signals (going through the MoCA bridge) have been steady for the last 3 hours at:


Downstream
Channel Frequency: 657001587 Hz 651000244 Hz 662998413 Hz 675000977 Hz
Modulation: 256 QAM 256 QAM 256 QAM 256 QAM
Signal strength: 2.8401 dBmV 2.7655 dBmV 2.7906 dBmV 1.9403 dBmV
Signal noise ratio: 37.936 dB 37.356 dB 37.936 dB 37.356 dB

Upstream
Channel Id: 9 7 8
Upstream Frequency: 22000200 Hz 36200144 Hz 29400296 Hz
Upstream bandwidth: 3200000 Hz 6400000 Hz 6400000 Hz
Transmission signal strength: 45.5000 dBmV 46.5000 dBmV 46.7500 dBmV


The downstream signals are what they were yesterday, but the upstream power levels are lower.

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Chzcat1

join:2012-06-11
Lutherville Timonium, MD
reply to Morac

My Zoom 5341J had this happen moments ago! It lost upstream bonding & wouldn't re-lock. Pulling the coax of the back fixed it. Hooked it back up & all is well again. Thanks to all of you that figured this out!



Morac
Cat god

join:2001-08-30
Riverside, NJ
kudos:1
Reviews:
·Comcast
reply to Morac

Things were still good this morning, but I kept my appointment because I wanted to know the status of the maintenance and the phone support no longer has access to that info.

Any way the tech noticed that I was off a splitter inside the tap itself. There are 4 houses off my tap and one of my neighbors has two drops. The tap only has 4 ports and I ended up being off a splitter connected to one of those ports. Switching me gave me the following great signals:



Downstream
Channel Frequency: 657001587 Hz 651000244 Hz 662998413 Hz 681002197 Hz
Modulation: 256 QAM 256 QAM 256 QAM 256 QAM
Signal strength: 6.0627 dBmV 6.1458 dBmV 5.9716 dBmV 4.6478 dBmV
Signal noise ratio: 37.936 dB 37.356 dB 37.936 dB 37.936 dB

Upstream
Channel Id: 9 7 8
Upstream Frequency: 22000131 Hz 36200117 Hz 29400258 Hz
Upstream bandwidth: 3200000 Hz 6400000 Hz 6400000 Hz
Transmission signal strength: 42.2500 dBmV 43.2500 dBmV 43.2500 dBmV


What a major difference. Now my downstream signals are a bit hot, but the SNR on my TiVo and modem is now 37. I'll need to watch it when it gets cold out as that will increase signals and might make it too hot, but for now it's good.

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