Broad question, I know, but my Surfboard 4100 keeps dropping its
connection to Cox. I have been reading some of the other inquiries here
re some of my problems, but none has answered this specific question.
The Cox tech and I have just started to troubleshoot the problem, but
one of the things he told me is that my modem may be going bad. Being
somewhat literate in electronics, computers, electrical circuitry, my
thought was that it would either work or not...all or nothing.
Is their claim legitimate? I don't mind getting a new modem, but would
like some input. The modem reconnects after I disconnect the power for a
few seconds, probably 90% of the time. Sometimes it re-establishes the
connection on its own, after 5-10 minutes, if left alone.
The technician suggested there may be some kind of feedback "building
up" in the modem that disables it as it accumulates. I admit, I didn't
write down what he said, but that is what I recall.

I'll enclose the signal data from the modem diagnostics.

This page provides information about the current upstream and downstream
signal status of your Cable Modem.

Downstream Value
Frequency 621000000 Hz Locked
Signal to Noise Ratio 27 dB
QAM 64
Network Access Control Object ON
Power Level -19 dBmV
The Downstream Power Level reading is a snapshot taken at the time this
page was requested. Please Reload/Refresh this Page for a new reading
HFC MAC Address 00:20:40:91:38:F4

Upstream Value
Channel ID 6
Frequency 24304000 Hz Ranged
Ranging Service ID 566
Symbol Rate 2.560 Msym/s
Power Level 47 dBmV


Thanks for any insight that you can provide.
T Gibb

Tgibb wrote:

Your SNR and DS Power look a bit low. I look for :

Downstream Receive Power: avg -15 to +15 (-10 to 0 preferred)
Upstream Transmit Power: -8 to +58 (+25 to +55 preferred)
SNR: 30 to 37 (>= 35 preferred)

Elmo P. Shagnasty wrote:

Sounds more like RF issues.


--
Fedora Core Linux Development Team
Kernel: 2.6.6-1.427
Registered Linux user #357785

Elmo P. Shagnasty wrote:
Maybe I am using the term "dropping" incorrectly. I lose my connection
on a regular basis...daily. ]
I don't "know" what is actually happening yet, and want all the
information I can gather, before following up on the problem tomorrow.
It sounds like you may have had a bad experience with Cox. I am
troubleshooting this problem at my father's house. I have the same setup
at my house (SB4100 and Cox), and it works great.
My naturally skeptical self thought they may be feeding me a line about
the modem to minimize their involvement w/ solving the problem (since it
is my modem)...less time, less cost to them.
Among the other possiblities, is the splitter I am using to feed my
modem and another splitter, to feed my television sets. At this point, I
want to get a direct line run inside the house to feed the modem. They
did that for me at my house. Hopefully, that will clear up the issue.

$Bill wrote:



Depends on how many homes passed and the ratio of upstream nodes in the
Reverse combiner gear at teh headend.

Anything above +27dB is good for DOCSIS 1.x or DOCSIS 2.0 (which we use
using SCDMA)

Most run 4:1 or 8:1 combining. Of course lower the better, but 35 is good
if you run 1:1 ratio.

E


--
Fedora Core Linux Development Team
Kernel: 2.6.6-1.427
Registered Linux user #357785

$Bill wrote:
Do these values originate w/ Cox, the provider?
(That question even sounds dumber, after I typed it, but what the heck.)
Or is it a faulty modem?

Egress wrote:

By that you mean, radio frequency issues on Cox's end?

Sounds like the tech is just making his best guess on the problem.
I worked in cable modem tech support for 3 years.
I only had one customer with a bad modem.

"Tgibb" <2heygibb@cox.net> wrote in message news:40CCF7B5.6060803@cox.net...

$Bill wrote:
speed reductions, and below 27 will usually result in loss of connection
periodically. This could be a modem problem, but probably is due to bad
connections, or a faulty amplifier along the line. Unfortunately, this
type of problem usually takes two calls to fix.

Tgibb <2heygibb@cox.net> wrote:
of analog in the RF section of a cable modem). Just like a television --
sometimes it goes out with a P-f-f-f-f-t and a puff of smoke, and sometimes the
audio gets fuzzy or the picture jumps around.

As to the likelihood...well, I'd sure want to rule out the more likely
candidates first.

Andy Hill wrote:
potential problem issues, but you answered the question I asked.
Now, I'll see what I can do to get things working correctly.

Followup to inquiry...
Cox internet tech came out, replaced all connectors and splitter from
street (said they were very old...6+ yrs). This got my SNR up to 32. My
connection has not been lost since.
He ran a signal test at the street where there was severe drop off on
high end. He then called in a work order to the cable tv side of COx,
who came out and replaced amplifiers and other hardware up and down the
neighborhood. After all that, I was informed the line coming to the
house had degraded to the point of having to be replaced. He could not
get the tv reception on the upper channels to come in clearly (all are
grainy). So, at Cox's expense, I'll be getting new cabling from the street.
THanks for all interested enough to respond. Your feedback was very
helpful in helping me understand the structure of a cable system.
Troubleshooting anything is best done onsite, so your willingness to
offer ideas was appreciated.
T Gibb