cable internet prob(kinda technical q)

[glockjs]

been having connection probs for awhile now after many trips from the techs from replacing the modem to replacing the trap the same prob still exists. after watching the modem stats i think i kinda figured out what it is.

the signal to noise ratio sporadically drops. it does anything from losing a few packets to 0 internet connection. and now they say the wiring in the apt has to be replaced.

i guess i wanna ask the question since i had to figure out somewhat of the prob myself while these trained proffesional monkeys couldnt. what would cause a sporadic change in SNR besides the wiring from the box to the modem? there are no splitters in the line btw.

[LloydAZ]

been having connection probs for awhile now after many trips from the techs from replacing the modem to replacing the trap the same prob still exists. after watching the modem stats i think i kinda figured out what it is.

the signal to noise ratio sporadically drops. it does anything from losing a few packets to 0 internet connection. and now they say the wiring in the apt has to be replaced.

i guess i wanna ask the question since i had to figure out somewhat of the prob myself while these trained proffesional monkeys couldnt. what would cause a sporadic change in SNR besides the wiring from the box to the modem? there are no splitters in the line btw.

I had a similar problem with my cable modem a few years ago in a complex that I lived in. We were always losing our internet connection. After a few flunkies at the cable company couldn't figure it out, a real technician came out and put a meter on the line. The voltage coming in the cable was too high. He put a filter on the line and we never had any problems since then.

I wonder if it could also possibly be one of your neighbors in the complex is tapping into the cable box unlawfully and throwing things out of whack. That might be why they want to rewire.

[InXess]

The best way to eliminate in-home wiring would be to connect the modem at the single point of entry to the house before it splits. Splitters (high quality - would not affect your connection, in fact this is how most houses are wired, cable co. supplies them).
If you have a dedicated line that goes to the modem it is simple. Just connect your modem to this cable and run a networking cable to the pc. Run a constant ping to your dns server, gateway or web servers like yahoo.com.
for example : ping /t www.yahoo.com (in cmd window - Windows XP) to stop it: Ctrl +C. Run it for as long as you need to determine whether you have uniform ping time (response).

If you have a single line supplying cable TV and the internet you may split the line with a highest quality (widest bandwidth) splitter you can get (Radio Shack...?). Put the modem on -3.5 db output and TV on -7db.
Do not connect the TV and run the same test. If OK connect the TV and watch if there is a difference.
You may be getting a feedback from your TV (need a special filter - cable company supplies them). Check if connecting a TV changes anything.

Test it at different times of the day but most of all in the evening (busiest time).

Your problem may be associated with:

- modem levels out of specs (call tech support and ask them what the levels are as well as the boundries as per specifications). On receive you should be around 40db (+/- 5). Your transmit levels ahould be around zero to -12db (e.g -3db would be good). Depending on local specifics there may be some deviances from values give, verify with tech. support.

- your levels should be rather steady (+/- 2 db) not fluctuating too much, that would indicate noise issue in the area.

- if levels and modem are OK try a different networking card (bad one may be affecting the modem)

- test wiring as described at the top.

I'm assuming that you have checked your PC and network card (NIC)beforehand. If not, be aware that your PC may be a culprit (bad NIC or drivers). To be safe replace your NIC with another one and proper drivers. All network troubleshooting rules apply here.

If all this is verified have a technician come with a meter to measure the noise at the modem.

This is not a definitive guide, just something to work with...

[Nelson37]

Had that exact problem on a new install, complete with several visits from cable company.

Finally I told them either get it working or take it out, and I would not pay any charges, which I had not paid any bills yet.

New tech came out, took one look at the cable from the pole, Said something like "why the hell didn't they replace that", immediatedly climbed up and ran a new wire from the pole to the house. Problem solved, never occurred again.

Apparently there were what looked from the ground like some splices in the cable, new wire did not have these.

[glockjs]

ghar. there is only one line that is not split at anypoint going to the modem. i only have cable internet hooked up no cable tv. i guess the line is a little old :/ so looks like that is the next step

the only stats that change on the modem really is the downstream SNR

[InXess]

Old lines (often wet, shorted, corroded connectos, cracking etc.) have shielding that may be good enough for TV but modems require new high quality cables (2-way communicators vs TV which is 1-way). If you suspect the line you should have it replaced if you can. Cable companies often run a temporary drop from a pedestal (junction box) to the modem to determine if the problem is associated with the existing line. This is easy in case of a separate house, more complicated in apartment buildings.

Best way is to have a tech put a temp drop in place and work upstream to the local amp. Tech support should be able to tell you if this is an indiv. problem and how much your values differ from other users (what are the specs on the whole node, how many modems are up/down and how many are in specs, would indicate potential building/area issue).
With the right (caring) and equipped technician (proper scope to measure noise - not every tech has them, only designated) this is a problem easy to address unless more users are affected and problem lies upstream in the network.