Stiv2k
Rm -Rf As Root
join:2002-07-22
Orlando, FL | reply to Coolbrz
Re: Terayon TJ210 question
Yeah the signal is probably good coming off the tap, but it just gets crapified going through all the splits 
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- Steve Bularca |
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cheech4cs
join:2003-10-24
Hollis Center, ME
| Also what are the Mhz on the splitters?? Correct me if I'm wrong but you want them to rate at least 1000Mhz. The standard ones/OLD ones are like 900Mhz. I was told that by a tech when the first came out. I ponder that thought because isn't the service on a loop?? Just a thought and what I've been told. |
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adambpsu
Adam
Premium
join:2003-02-08
Harrisburg, PA
| said by cheech4cs  :
Also what are the Mhz on the splitters?? Correct me if I'm wrong but you want them to rate at least 1000Mhz. The standard ones/OLD ones are like 900Mhz. I was told that by a tech when the first came out. I ponder that thought because isn't the service on a loop?? Just a thought and what I've been told.
Yes, you need a splitter ranging to the 1000 MHz range. I think that they are rated 5-1000 MHz. I could be wrong too, but I thought that I remembered this correctly.
What do you mean by a "loop?"
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Adam...Uh, someone broke the internet again! |
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MacLeech
The one and only
Premium
join:2001-07-14
SoCal
| reply to cheech4cs
said by cheech4cs :
Also what are the Mhz on the splitters?? Correct me if I'm wrong but you want them to rate at least 1000Mhz. The standard ones/OLD ones are like 900Mhz.
The highest frequency the vast majority of cable systems might use at this time is about 860 Mhz. So it doesn't matter if the splitter is rated to 900Mhz or 1000 Mhz as long as its above the highest frequency used in your local system for services you're recieving.
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Adelphia - Is it working now? |
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adambpsu
Adam
Premium
join:2003-02-08
Harrisburg, PA
| said by MacLeech :
The highest frequency the vast majority of cable systems might use at this time is about 860 Mhz. So it doesn't matter if the splitter is rated to 900Mhz or 1000 Mhz as long as its above the highest frequency used in your local system for services you're recieving.
Ahhh. That makes sense. I never thought about how high the frequency actually. Since I never knew differently, I just always assumed since the splitter was rated for 1000 MHz, that is how high a frequency the system was using. Thanks Mac.
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Adam...Uh, someone broke the internet again! |
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Exceles
join:2002-10-05
Fredericksburg, VA | reply to Exceles
Not sure about the freq., but I can easily find out when daylight comes tomorrow (along with 4+ degrees of warmth too!). |
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Exceles
join:2002-10-05
Fredericksburg, VA
| reply to Exceles
Ok a followup. The tech came out monday and fixed the signal issue by locating the line the modem was on and placing it on the first split.
Even since then I've had no problems.
All is well.
Thanks for all the help
New levels:
Tx Power 22.2 dBmV
Rx Power 13.9 dBmV
Downstream SNR 32.2 dB
Tx Frequency 34000000 Hz
Rx Frequency 573000000 Hz |
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Stiv2k
Rm -Rf As Root
join:2002-07-22
Orlando, FL
| well your SNR is in range, that's good, but your downstream signal is quite high, although I believe DOCSIS supports up to 15 dB...
Your upstream signal is way too low, you want that to get up in the 40's :/
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- Steve Bularca |
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adambpsu
Adam
Premium
join:2003-02-08
Harrisburg, PA
2 edits | said by Stiv2k :
well your SNR is in range, that's good, but your downstream signal is quite high, although I believe DOCSIS supports up to 15 dB...
I would agree. However, if he is not having any problems, then I would just leave it as it is. I know, like you said, that it seems high, but he should be okay.
The lower the better. He should be fine.
All in all though, not the best signals I have ever seen. Maybe you can even get those amended even more if you have troubles?
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Adam Number Two...
"They have the internet on computers now?" |
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MacLeech
The one and only
Premium
join:2001-07-14
SoCal
2 edits | said by adambpsu :
The lower the better. He should be fine.
Wrong, if a signal level is too low it starts getting into the noise, in this case you would see this as a lower SNR on the upstream. Too low of an SNR and the receiver can't differentiate the signal from the noise.
For upstream you want the level as high as possible without getting into the region of signal variations due to weather or minor plant cable changes that would push the modem over a transmit level of 58 (or 55 depending on QAM used) dbmv. 40 - 50 dbmv is nice.
Also lower upstream levels mean the cable system is more vulnerable to ingress and noise coming from subscribers drops (since its not attenuated as much as it should be). This causes even more issues to modems with low transmit levels because then they have to compete with that noise as well.
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Adelphia - Is it working now? |
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adambpsu
Adam
Premium
join:2003-02-08
Harrisburg, PA
1 edit | reply to Exceles
Good call Mac. I guess I wasn't thinking, as I have always wondered what exactly determined the lower limit in the DOCSIS standard. Thanks for correcting me on that. |
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