Cable Internet RF issues

This may be a Network Issue and Maybe Not But. My Cable Internet has been shut off. The Cable television is still working. Comcast says that its been filtered because of RF leakage. The Comcast Rep cant give me any answers as to what would cause this. Inside my Home I have a rack with a PDC, a DNS server, a File Server. and multiple nodes. Everything is connected with an older 24 port 10/100 switch. The gateway is a Linksys wrt54g connected to the Motorola cable modem. The cable drop for internet is direct from an outside splitter that Comcast Installed. There is nothing on the Internet drop except the cable modem. My question? Can you see anything thats on the internal network that could cause RF leakage this extreme? And if not, Do you have any ideas about what could be the cause? Ive been down 3 days waiting for Comcast to service this.

So who's the cable provider ? Am I being thick ? .. because at the minute I'm thinking its Comcast ..

So they've shut your cable Internet off, because their own equipment is causing leakage onto their own RF circuits ? A brilliant bit of customer service that sounds ! NOT !!!

Cable TV & whatnot in, must be analogue then & not like here digital ? Else there'd be no RF anywhere anyway to be leaking back in & cross interfering ..

This really makes no sense to me whatsoever, except to say that Comcast seem to have a severe case of 'left hand/right hand' !

Since you're off the internet you have nothing to lose.

Before that, is this a business service? If so, have them send a tech over and track down the interference, it's their damn job to start with and frankly, there are plenty of people willing to provide business level ISP service. Use that as a threat althought this experience might be a good reason to switch.

As confused said, cable is an analog technology and cable TV singles could have a higher tolerance to interference than cable internet. I would disconnect everything from your cable singal when you call them to rule out any of your entertainment equipment.

Reason for that is, as I've said, your cable TV singal could have a higher tolerance and interferes with your cable internet, but only their cable internet is experiencing problems, so they filter that out. I would not rule out interference from your entertainment system outright.

But since you're off the internet anyway, put one machine on the cable modem and call them again and ask if they still detect interference.

If so, connect nothing to the cable modem while they're on the phone and ask them again. If they still detect interference, guess whose equiptment is faulty? Not yours.

But have another machine standing by and powered up to connect to the cable modem to rule out the first PC as the one providing the interference, remember that most cable modem requires a reset to provide service to a new equipment on the line.

Try to keep them on the phone while you do all this and finally, I would ask what they're going to do to help you track down the interference. Be polite, but insistance. You're trying to force an escalation of your trouble ticket so they'll take you more seriously. Tell them that nothing has changed on your end (equipment wise) and if there is some interference to their line introduced outside your house what is their responsibility in tracking down the problem.

But you get the idea, you're trying to get them off their *** and do their job.

Other than that, what kind of PC do you have? DIY? Are they overclocked? If they are, don't use those for testing. I would immediately rule out brand name boxes (computer and switches and so forth, unless they're going bad.

Most of what I'm telling you is also something they should have troubleshoot with you over the phone if you have a business line or you had them escalate your trouble ticket.

Good luck.

Sorry, but your are going about this the wrong way.

Cable is a closed system, as such, the CRTC/FCC allows cable providers to broadcast on any frequency through those wires that they choose to use. However, that signal cannot leave the wire, this is why cable wires are so heavily shielded.

They can get heavely fined if their signal leaks out of the wire into the surrounding neighbourhood, this can cause problems with CB radios (interfere with police), paging systems (interfere with hospitals) and other devices. This is what RF leakage is.

Signal from outside leaking INTO the wire is called ingress, in some situations there is nothing that can be done to prevent it, this would cause an issue with you and depending on the source, you would be told to live with it, Hospital neir by? Expect channel 17 to screw up all the time.

Confus-ed, even digital signals are carried over an RF signal, the difference between digital and analog has to do with how the signal is encoded into the RF stream. (i won't go into those details here)

RF leakage is usaly caused by poor cable equipment, specialy nicks/poor cabling, faulty grounds, things like that..

If they have disconnected service due to this, there is nothing that can be done remotely, even if you find the leakage source, they can't detect it remotely, so your still waiting for a tech.

I know in canada, they have vollontary regulations on how quickly service techs come out. For example, if you have no TV, nothing, then you will usualy find yourself with a tech comming out within 24 hours. Internet does not fall under these standards. So *cough* disconnect your TV and *cough* call tech support for no TV service.

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Originally Posted by Matridom

Confus-ed, even digital signals are carried over an RF signal, the difference between digital and analog has to do with how the signal is encoded into the RF stream. (i won't go into those details here)..

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Err I know about digital vs analogue - think waves vs morse code .. but 'cable' here is all on optical networks as far as delivery goes - & you can't get RF ingress or leakage on that can you ?;)

If they are saying that RF interferance is a problem to their transmitting equipment, then they must also use copper based medium in their transmission systems, here the stuff in the ground is carried in optical cables, as its all new & was only allowed to be laid over the past few years, not like the us where you've had copper based 'cable tv' for years :)

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Originally Posted by confus-ed

Err I know about digital vs analogue - think waves vs morse code .. but 'cable' here is all on optical networks as far as delivery goes - & you can't get RF ingress or leakage on that can you ?;)

If they are saying that RF interferance is a problem to their transmitting equipment, then they must also use copper based medium in their transmission systems, here the stuff in the ground is carried in optical cables, as its all new & was only allowed to be laid over the past few years, not like the us where you've had copper based 'cable tv' for years :)

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Most places use optical as a major part of the transmission, however, the finaly "mile" is 99% copper, just about everywhere, I seriously doubt that your TV as an optical input for it's signal. The fiber/cable switch over usualy occures at the node (street level)

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Originally Posted by Matridom

Most places use optical as a major part of the transmission, however, the finaly "mile" is 99% copper, just about everywhere, I seriously doubt that your TV as an optical input for it's signal. The fiber/cable switch over usualy occures at the node (street level)

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http://www.telecast-fiber.com/Graphics/STCU.jpg
http://www.telecast-fiber.com/artman...blue-thumb.jpg
Both of those are coax to fibre converters, found on the end of every 'cable tv' box I ever looked at in the uk, the final 5 yards is copper here not the last mile - just so it fits in the tv easy & doesn't break & not for any other reason, I'd have thought ..

& I'm saying this, as this is the last point where RF ingress would be possible in the uk, but I dunno why the hell I'm having this arguement ?

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Originally Posted by confus-ed

& I'm saying this, as this is the last point where RF ingress would be possible in the uk, but I dunno why the hell I'm having this arguement ?

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Cause we both enjoy a good discussion?


In the america's it's a little different, I've been doing cable internet/tv support for years now, I know more about the systems here in canada then i care to admit to...


p.s. I also forgot you are from over the pond...

And in the US, at least around here, they are just beginning to lay the fiberoptic in a lot of places..it's still copper for a lot of smaller towns, etc.

Thanks for the Help .. The result after not having Internet for 4 days. Three calls to the Provider , 2 Service calls later .. The stinger ( end of the wire in the coax) on the pole was nearly 1.5 inches long and jammed thru the connector to the other side causing a major rf leak. This was from the original install over 5 years ago. We wont even mention the technician who couldnt figure out why the cable modem would connect but the router was still offline .. I actually Had to reboot the router for him to sync the router with the modem. Anyways it would have been nice if they had knocked on the door and told us they were disconnecting. Thanks again

So comcast finally figured out that RF ingress is their problem no matter what you've got connected to it & sent an engineer ? (As I don't think anybody actually said it, but I got the feeling lots of us were busy thinking it !;))

Anyways its fixed now, & that's the entire point ! :)

Well I did mention that he had to somehow get his provider off their butts and do their job. Even if he was SOL because of outside interference, how is an end user suppose to figure that out? It was really up to the provider technicians to figure it out for him and give him a satifactory answer even if there was nothing they could do.

Now find out if they'll charge you for the 4 days of what is basically their problem.