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d4m1r

join:2011-08-25
Reviews:
·Start Communicat..

Signal Level Changes

Hey guys, recently I've been noticing a change in my modem signal levels....Basically, I used to get both Rogers cable TV and internet into the house but now we have Start and we recently cancelled the cable TV all together. The Rogers guy came and did some work in the cable modem box on the side of the house but did not change anything in the basement where the splitter is. Anyway, previously for years my downstream power level hovered around 0 or -1 which is exactly in between where you wanna be (-8 and +8 generally).

Since the Rogers left though, it sits at +4 and I don't like that because I am closer to having problems by going over that range. Modem is a SB6120 and now cable internet is the only cable service going into the house and I do believe the splitter is still connected (not sure if that matters).

»i.imgur.com/Wdhyw4x.png
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www.613websites.com Budget Canadian Web Design and Hosting


Scycotic

join:2012-12-10

If you aren't having problems...why worry? But a while back we had a signal attenuator on our line after we had issues for a while. Might help you, since if I understand correctly your signal's too strong...?



Gone
Premium
join:2011-01-24
Fort Erie, ON
kudos:4
reply to d4m1r

The signal level varies based on temperature. I you're at +4 today it'll probably be near 0 in the middle of summer and ~8 in the dead of winter.

I wouldn't put an attenuator on unless you were blowing past +12 in winter. The modem I'm typing this through right now is at +7 with eight downstream channels and it still works fine with an SNR above 40 on all eight channels.



DrugTito

join:2013-01-17
canada

This is happening to me as well, i am sure that damir already saw my thread :P



d4m1r

join:2011-08-25
Reviews:
·Start Communicat..
reply to Gone

said by Gone:

The signal level varies based on temperature. I you're at +4 today it'll probably be near 0 in the middle of summer and ~8 in the dead of winter.

I wouldn't put an attenuator on unless you were blowing past +12 in winter. The modem I'm typing this through right now is at +7 with eight downstream channels and it still works fine with an SNR above 40 on all eight channels.

Actually, if I am remembering it correctly it was stable all year round....Maybe 0 in the summer and -1 in the winter. I know for a fact just this past winter it was hovering around these power levels as well so I am more inclined to believe it was something the Rogers guy did (possibly a filter he installed to block cable TV?).
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www.613websites.com Budget Canadian Web Design and Hosting


Gone
Premium
join:2011-01-24
Fort Erie, ON
kudos:4

Copper expands as temperature increases and contracts as it decreases. Your signal levels are directly related to the length of copper between you and the nearest amplifier. Expanded copper in the summer = longer length between you and the amp = lower signal levels in summer. It is impossible for your levels to stay the same all year unless you are literally within reaching distance of the the amp. There is going to be some movement up and down throughout the year. Hell, the drop to my house is right next to an amp and even I see a bit of loss in the summer compared to the winter.



JCohen
Premium
join:2010-10-19
Nepean, ON
kudos:11
reply to d4m1r

Did the tech remove a splitter since your cancelled your cable TV? If so that would cause a 3.5dBmV increase.



d4m1r

join:2011-08-25
Reviews:
·Start Communicat..

said by JCohen:

Did the tech remove a splitter since your cancelled your cable TV? If so that would cause a 3.5dBmV increase.

Would have have been done in the basement? Which is where the lines from the cable box outside run to...In which case I'd say no because he never went to the basement and I still see a splitter on the coax line down there.
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www.613websites.com Budget Canadian Web Design and Hosting


Oinktastic
Let them use fibre

join:2005-08-24
Scarborough
kudos:2
Reviews:
·localphone.com
reply to Gone

said by Gone:

...
Expanded copper in the summer = longer length between you and the amp = lower signal levels in summer.
...

That's an interesting way to remember the ups and downs of your signal levels, but I thought the seasonal changes have much more to do with moisture levels rising in the summer.


Gone
Premium
join:2011-01-24
Fort Erie, ON
kudos:4

Moisture shouldn't cause too much to change unless you've got a bad connector somewhere.



d4m1r

join:2011-08-25
Reviews:
·Start Communicat..

4 edits
reply to d4m1r

Ok, it's been raining for 2-3 days straight here and it's changed again....When it is sunny, warm, and dry it, my downstream signal level now hovers around-2/-3. Right now it is -4/-5, too close to the -8 threshold recommend with my modem (SB612) for my liking.

I am now looking into a signal attenuator because my signal is seemingly too strong and the problem is aggrevated by moisture (does that even make sense? woulda thought the opposite). Anyway, what kind of signal attenuator should I get? I'm assuming there are different grades.....Also, can I place it any where after the splitter and before the modem including attaching it directly to the modem?

Let me know and thanks in advance guys.
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www.613websites.com Budget Canadian Web Design and Hosting



Gone
Premium
join:2011-01-24
Fort Erie, ON
kudos:4

Your signal is weak, not strong. Installing an attenuator or a splitter is only going to further reduce the signal level.

DOCSIS is spec'd for -15 to +15 per forward channel. Between -4 and -5 is fine and something the cable company won't even say peep about. -8 is fine so long as your SNR is still good and the channels are bonding. So is +8. -12 and +12 is where one would start to be concerned, not -8/+8. Seriously, you're getting into a tizzy over nothing.



d4m1r

join:2011-08-25
reply to d4m1r

Sorry, I corrected the original numbers...They aren't negative but positive.



Gone
Premium
join:2011-01-24
Fort Erie, ON
kudos:4

+5 is perfectly fine. You seriously have zero reason to be worried. When it gets above 10 or 12 then you have reason to keep an eye on it.