psldave
join:2003-07-31
Port Saint Lucie, FL
| Upstream off the chart: Downstream unchanged... I've been trying for several days to get connected long enough to ask the forum about my connection problem so that I might respond with some understanding when the tech arrives on Saturday (1/10) to evaluate the situation.
Here's the low-down:
One week ago the signal strengths reported by my modem (Linksys BEFCMU10) changed radically. After passing through the house splitters, the downstream was -18dBm (SNR 32) and the upstream was 47dBm. Each was not optimal, but worked fine.
Friday, the connection disappeared.
I carried the modem in to the attic and connected the modem to the cable before any splitters - as expected, the downstream got much better (-2.4 dBm), but the upstream was 10dBm worse - all the way up to 56.5dBm!
Sounds like an upstream amp is out???
Comments are welcome - hope I can get connected to read them before the tech arrives - thanks gang. | |
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 jojodancer
join:2003-07-22
Burlington, VT | Re: Upstream off the chart: Downstream unchanged... What is an upstream amp? | |
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panth1
The Coyote
join:2000-12-11
Boca Raton, FL
| Some amplifiers on the system have a reverse amplifier for the upstream. Depending on the design of the system and how many are cascaded from the fiber node, they may or may not be used.
With many people working on the system and constant changes, signal levels can change every day.
Explain to the person that you see the upstream has increased dramatically the past day(s). Make sure that the tech fowards the problem to the maintenance crew and get everyones name you talk to.
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ISPs: Road Runner/Powerlink Status: Road Runner | |
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prisoner3
join:2003-09-15
Lockport, NY
| Actually you want that lower, definitely under + 58dBmV
which is the acceptable limit. The splitter will lower the dB slightly (higher before the splitter, lower after.) An
old cable installer trick is to put in an extra splitter if dB is too high. ( too high just as bad as too low)
Downstream channel of -18dBmV(-15 to +15 OK) looks bad, may need to be addressed. Let me know how the house call goes. | |
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 | psldave
join:2003-07-31
Port Saint Lucie, FL
| Re: Upstream off the chart: Downstream unchanged... said by prisoner3  :
Actually you want that lower, definitely under + 58dBmV
which is the acceptable limit. The splitter will lower the dB slightly (higher before the splitter, lower after.) An
old cable installer trick is to put in an extra splitter if dB is too high. ( too high just as bad as too low)
Since the upstream is how much power the modem is having to transmit back up the cable, adding splitters will only make the modem have to work even harder to get a connection. The modem's upstream is maxed now - adding a splitter now causes the connection to fail - the SNR upstream isn't good enough for a solid connection due to low signal level. | |
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CableMan
join:2002-01-22
South Glens Falls, NY
| did you reboot the modem when it was hooked up in the attic? your upstream(reverse) should have been lower if it was before all of the splitters. this is why most people will say "make sure it is off the first splitter". technically your upstream should have dropped down to almost 31-33 dBmV range.
56 is optimal but very close to the edge. is there an inhouse amp in the attic or before the attic?
your 47 up is fine but your -18 down is terrible. | |
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psldave
join:2003-07-31
Port Saint Lucie, FL
| Resolution: The tech visited this afternoon and got things rolling for me in short order. She determined that the drop from the street to the house was bad. The new line is currently laying across the yard; she'll be back in a day or two to trench it in.
Modem Function: The modem now reports a downstream signal of -6dBmV (with splitters in place) and an upstream signal of 44dBmV. These are far better signal strenths than I've seen since I started using Powerlink over a year ago. My SNR is up to 35.
I would have to say that the Adelphia tech did a great job for me. Very favorable reflection on the company.
Dave in Port Saint Lucie, FL | |
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