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colbond

join:2012-12-02
Broomfield, CO

[Signals] Intermittent signal loss, Comcast HSI Denver area

Click for full size
Logs
Click for full size
Right after I notice problems

Eventually lose all the channels
Click for full size
Later, after the modem reboots
This has been going on ever since I moved into this apartment, but seems to have gotten worse recently. As frequently as two or three times a day, and as infrequently as every few days, my connection speed will slow to a crawl, then die completely, over the span of maybe 5 minutes. Checking the signal stats page of my Motorola SB6121 usually shows the following pattern: of the 4 downstream channels, one or two will have a SNR below 30 and Power Level of -8 to -12. Shortly after that that channel or channels will fall out of bonding, and the remaining channels will lose signal and drop completely. Upstream always looks fine until I start losing all my downstream channels. If I let the cable modem sit long enough, usually 15-20 minutes, it reboots and comes back up with a signal. It doesn't always bond all 4 channels right away. The logs will show T3 and T4 timeouts. Comcast has run health checks on my modem several times and re-provisioned my service, but I can never get them on the phone right as the problem is happening, so they never see the issue. They sent a tech out who switched the direction of a tap to give my modem the best signal possible, but I'm still seeing the issue. Living in an apartment I don't have much control over the wiring, but I was able to completely eliminate one splitter. I have also replaced my cable modem since the issue started.

Any advice? Comcast is sending out another tech, and this time they said they'll be checking the drop from the pole to my apartment. Let me know if I missed any information. Thanks!

ExoticFish

join:2008-08-31
Stuarts Draft, VA

Go here: »192.168.100.1/cmConfig.htm Reset all defaults, then restart the cable modem. I doubt that will fix anything but try that first. Your downstream signals are all off. There shouldn't be that much of a variation in signal. Post back with your results.
--
»www.VAJeeps.com
»www.BronzedBod.com


colbond

join:2012-12-02
Broomfield, CO

Doing that right now. I agree it probably won't help, especially since it seems to have only happened since moving to this location. It started with my SB 5100, which I replaced with this SB6121. I can see more of what's happening now that I have a DOCSIS 3.0 modem with bonded channels, but other than that the symptoms are the same.

Comcast tech should be here in a couple hours. I'll give it a day or so and see what they have to say.



beachintech
There's sand in my tool bag
Premium
join:2008-01-06
kudos:5
reply to colbond

You have a major wiring issue. Call for a tech, and keep calling until its resolved. It may result in wiring needing to be replaced in your apartment.
--
Ex-Comcast Tech at the Beach. I speak for myself, not my former employer.


colbond

join:2012-12-02
Broomfield, CO

That wouldn't surprise me. The first tech who came out had some notes explaining how bad the wiring was. I kind of let that go since 90% of the time I have a perfect signal and am getting exactly the speed I pay for.

Anything specific I can point to or look for? Or anything I can do to help alleviate the problem while I'm living here?



beachintech
There's sand in my tool bag
Premium
join:2008-01-06
kudos:5

Just let the tech do his job with a meter. Without being there with the tech and an SLM, I can't tell you whats wrong specifically. It could be the signal coming in to the building, but more than likely its the wiring in the walls.
--
Ex-Comcast Tech at the Beach. I speak for myself, not my former employer.


timtom

join:2012-11-15
reply to colbond

said by colbond:

That wouldn't surprise me. The first tech who came out had some notes explaining how bad the wiring was. I kind of let that go since 90% of the time I have a perfect signal and am getting exactly the speed I pay for.

Anything specific I can point to or look for? Or anything I can do to help alleviate the problem while I'm living here?

Where do you live exactly?

colbond

join:2012-12-02
Broomfield, CO

said by timtom:

Where do you live exactly?

Westminster, CO. Suburb of Denver.


flwpwr

@comcast.net

Move all equipment out from cable outlets. ALL OUTLETS EVEN ONES YOU DO NOT USE. Insist he or she change ALL fittings. Commonly no one opens apartment outlets up for whatever reason generally people have shit in the way, and the fittings never get changed, this causes all sorts of noise, and issues. First visit if all fittings/splitters get changed, the tech will also look at the wires and note if they are solid polycore, have no shielding, etc. and need to be changed. If that is the case, it may NOT be comcast's responsibility to do this unless the contractual agreement with the MDU providers says it is, otherwise you are at the mercy of your land lord, and if they don't want to pay to get the right wires in there, you are screwed, go with DSL and hope the phone lines are in better shape.

Second if you have any store bought coax, ask them to give you one of theirs, lots of time this has fittings that are broken up inside the plastic sleeve, the wrong shielding, or fittings with such a small hole where the stinger passes though it shorts half the time.

Good luck.


colbond

join:2012-12-02
Broomfield, CO

That's just about where I'm at already. There are only 3 outlets total. I've swapped a splitter for a barrel to remove one of those, the other outlet is buried behind a bookshelf and I need some serious time to mess with it. I don't even know where the splitter is that feeds that outlet anyway, I'm hoping it's right behind the wall plate. The one I removed *may* have been daisy-chained to feed that third outlet anyway. All my wiring is modern, shielded coax and I've used a tap to feed the TV to give my modem the best shot at a good signal.

I'm prepared for the possibility that the management company may be responsible for the wiring and unwilling to do anything about it. Once comcast can rule out the drop and my equipment, at least we can both be on record as saying it's a problem with the building and I may have some legal backing to have them fix it (they advertise it as being cable-ready, and it isn't). I can post pictures of the exposed wiring if it'd help. I'd replace the affected wiring myself if I had access to a crawlspace.


colbond

join:2012-12-02
Broomfield, CO

Obviously the only way to tell will be giving it some time, but the tech came out and immediately said the problem was the old fittings on the (ridiculously) old wiring in my apartment. He replaced that, replaced the tap with a newer splitter, and boosted something on his end. He also said something about the cable modem not being registered, which he eventually resolved. I would have asked more about what he was doing, but he looked to be in a pretty big hurry.



beachintech
There's sand in my tool bag
Premium
join:2008-01-06
kudos:5

The way they schedule techs, they get about 40 minutes or so for a trouble call. That includes getting there, taking levels in a few locations, talking to you, doing paperwork, and solving the issue. It's a crappy system if there is a lot going on that day.

Did he replace the fittings behind the wallplates? Keep calling until its resolved, and don't cancel the call if it seems fixed.
--
Ex-Comcast Tech at the Beach. I speak for myself, not my former employer.


colbond

join:2012-12-02
Broomfield, CO

I believe it. It's probably cheaper for them to pack in appointments and pay a $20 credit once in awhile than schedule an appropriate amount of time.

He replaced the one fitting that was relevant to the cable modem (I don't use the other two outlets and since I'm renting, I'm not too interested in putting a ton of effort into upgrading the existing stuff). So far it's looked good, but I'm sure it'll take a day or two to know for sure. Should I still have them come out and check from the pole to my building? I'm not sure how I'd justify that to them if I haven't had issues since this last visit.



beachintech
There's sand in my tool bag
Premium
join:2008-01-06
kudos:5

Your signals that you posted are horrible and I am surprised you are online. They still need to come out. There should not be more than a 1dBmV variance between channels.
--
Ex-Comcast Tech at the Beach. I speak for myself, not my former employer.


colbond

join:2012-12-02
Broomfield, CO

That's actually good to hear. When I tell Comcast what my signals are, they don't seem especially concerned. The biggest trouble is that being an intermittent problem I haven't had them on site or on the phone right when it's happening.


timtom

join:2012-11-15
reply to colbond

I meant exactly. I am tech I work there.