Coax questions

[ibanezfoo]

You can if you strategize correctly. From the panel you can use a 1-2 with one leg to the modem and the other to another splitter or distribution box. I'd avoid using amplified distribution as it also amplifies the noise. DVRs can handle a little more signal degradation than a modem.

A 2 way splitter will have a ~3db loss, 3 way ~4.5db loss, 4 way ~6db loss etc.

There is such a thing as having too hot of a signal coming in and in that case an attenuator should be used but a splitter can help drop it a little as well.

If you have easy attic access or a decent crawl space under a raised house its pretty easy to recable.

[Marauder2003]

He has been lied to by multiple Spectrum techs. He just wants to eliminate their concerns 1 easy step at a time. Re-wiring the house is not an option.

You can if you strategize correctly. From the panel you can use a 1-2 with one leg to the modem and the other to another splitter or distribution box. I'd avoid using amplified distribution as it also amplifies the noise. DVRs can handle a little more signal degradation than a modem.

A 2 way splitter will have a ~3db loss, 3 way ~4.5db loss, 4 way ~6db loss etc.

There is such a thing as having too hot of a signal coming in and in that case an attenuator should be used but a splitter can help drop it a little as well.

If you have easy attic access or a decent crawl space under a raised house its pretty easy to recable.

[ibanezfoo]

He has been lied to by multiple Spectrum techs. He just wants to eliminate their concerns 1 easy step at a time. Re-wiring the house is not an option.

[Robotron2k84]

Depending on the make / model of cable modem, it may have a client-accessible management page that will show signal strength and channel parameters. That can be a good source of info as you test, and obviate the requirement for an external meter.

Remember that not only does the quality of the cable impact the signal coherence, but cable modem streams are broken up by CATV channels and then bonded inside the modem. Poor cable can affect different channel frequencies differently, and depending on the cable co.’s deployment configuration they may have chosen channels that have poor “reception.”

Also RG-6 is necessary for the newer QAM schemes because the additional harmonics introduced are attenuated properly.

[IronsightsRifleman]

Maybe the cable is fine and the "booster" amp has gone bad, or is just too old to pass the new signals. Try bypassing it.
It's unlikely a run of coax in an attic has gone bad, unless a rat chewed through it. An end exposed to the weather outside might degrade.
But if your friend wants to replace it just make sure he gets a cable of the proper impedance, I think 75 ohm for cable TV.

[ibanezfoo]

Depending on the make / model of cable modem, it may have a client-accessible management page that will show signal strength and channel parameters. That can be a good source of info as you test, and obviate the requirement for an external meter.

That is a good point. You don't necessarily need a meter. I have one and never use it. Look on the bottom of the cable modem for the login info.

If you can get into the outside box (sometimes they are just screwed closed, other times you need a specific tool you can get from amazon for 10 bucks) you can plug the cable modem straight into it and check your signalling there. That will tell you for sure whether its inside or outside wiring. You will have to take the modem and a laptop outside.

I had Spectrum tell me once it was my house wiring but since I know more than them I called them out on their BS and bodyslammed them with data. They sent a tech that knew his stuff and found a crack in the distribution block on the pole outside and then ran all new cable across my property (in a thunderstorm no less... I told him he could come back later but he insisted. I said ok I'll stand here and watch in case you get blown up by lightning).

Spectrum has been pretty good to me but out here they contract with a company called Genesys which is actually pretty good.

[Marauder2003]

Friend has measured output from the Spectrum coax and all the outputs from all the splitters.

db ranged from -1.2 to +5 at all outputs. And kept changing as he watched it.

He has no problems with picture quality, recordings or the internet. He has decided Spectrum is incompetent.

Case closed.

Now, for my own edification do DVRs transmit anything back to the company? Spectrum called and wanted to check out the DVRs. They did not say what the problem was. Tech checked serial numbers on the 2 DVRs and confirmed the problems were from him. And the tech blamed his inside wiring.

[Robotron2k84]

Depends on the DVR. If they use head-end channel selection instead of a tuner on the device, then yes.

Otherwise they are mostly passive devices and may only send authentication data to the upstream infrastructure.

If the attenuation was varying quickly, one of the amps is probably bad and injecting noise.

[andy342]

Do you really need to keep the DVRs?

Could just put the modem very close to where the coax enters the house. And then just cut the rest of the long cable and not use it.

[Marauder2003]

House is long. Spectrum enter house at garage end. Office and bedrooms are at other end of house. Wife records soaps so at least 1 DVR is needed.

User has no problems with internet or TV. Spectrum is claiming problems but no tech is willing to explain what they are.

Do you really need to keep the DVRs?

Could just put the modem very close to where the coax enters the house. And then just cut the rest of the long cable and not use it.