olo131

DOCSIS 3.0

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Well, Welder, that may be true in Kingsport, but not here. We were told to run 20's out. Also, we as system techs do our own sweeping, not contractors from West Tenn Utilities.

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I guess I can explain why since you brought it up. You have an LE running 38 on return (the standard). 23 val tap. That makes 41 return out that tap. Let's say 100 ft drop. That will give you 42 on return at the end of your drop. 4 way splitter makes 49 out the splitter on return. Let's go with a big house (we have a lot of them here) Your in house run is 100 feet to the modem. You're setting at 50 on return and it's out of spec. That's why we were told to go to 20 out.

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We did the same in my system except it was all the 26's and 27's we changed to 23's and our return is running out 40

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[quote name='System Tech Senior' date='03 October 2010 - 09:50 PM' timestamp='1286160608' post='142916']
Well, Welder, that may be true in Kingsport, but not here. We were told to run 20's out. Also, we as system techs do our own sweeping, not contractors from West Tenn Utilities.
[/quote]

So can i ask who told you. Edited by welder1994
to fix quote

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[quote name='olo131' date='03 October 2010 - 07:04 PM' timestamp='1286161470' post='142919']
We did the same in my system except it was all the 26's and 27's we changed to 23's and our return is running out 40
[/quote]

Are you guys talking about Tx levels out of an active? Just curious.

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Welder, Tony Fox is a Director not a Supervisor, and i'm pretty sure he wouldn't appreciate you throwing his name all over the internet like you have done. I'll make this simple. You do what you do, and we'll do what we do.

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Tx's of a modem, but levels at the active...... did that make sense?

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Got anything else Jonathan???

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Don't you guys set up return by Telemetry. Tx ranges too much. We use 0dB @ Nodes and Amps. We use 8 dB for LE's. Example: 8 db @ LE's. We inject @ 40 dB for SA III LE. 40-20db test point=20. 20-12dB @ chip(12)=8.0 Telemetry for LE. Our nodes run out @ 38TX/ 0 dB Rev Telemetry. Our Amps SAII(inject @ 40 @ =20 test point) and Motorola MB100(inject @ 28 though it's a -16dB injection point both are typically Tx-32-34. Interesting how our systems differ.

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Telemetry when sweeping, but not for a rough balance. We have docsis capable return test meters.. DSAM 6000's.

I sweep though.

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[quote name='System Tech Senior' date='03 October 2010 - 06:56 PM' timestamp='1286160964' post='142917']
I guess I can explain why since you brought it up. You have an LE running 38 on return (the standard). 23 val tap. That makes 41 return out that tap. Let's say 100 ft drop. That will give you 42 on return at the end of your drop. 4 way splitter makes 49 out the splitter on return. Let's go with a big house (we have a lot of them here) Your in house run is 100 feet to the modem. You're setting at 50 on return and it's out of spec. That's why we were told to go to 20 out.
[/quote]

41Tx @ 23 Tap? In our system a 23 Tap H-H out of the LE would be 35Tx. That's -23 for the tap portloss plus the loss of 12 for the return chip loss =35Tx.

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What's your amplifier running on return? if it's 38, it's impossible to have 35 out of a 23 value tap. 38 level on the -20dB test point puts 18 on the cable. 23(tap port loss) plus 18 (line level) equals 41.

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if you have 35 out of a 23 val tap h2h'd to an LE, then that LE is running 32 on your reverse.

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[quote name='System Tech Senior' date='07 October 2010 - 05:55 PM' timestamp='1286502935' post='143111']
What's your amplifier running on return? if it's 38, it's impossible to have 35 out of a 23 value tap. 38 level on the -20dB test point puts 18 on the cable. 23(tap port loss) plus 18 (line level) equals 41.
[/quote]

It's an Le. 13's on return in for LE's and our design input @ Amps is 15. But simply take the tap size say 23 plus the return chip loss(-12) and bypassing the internal test point(the tap is the test point!)=35Tx.

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I'm calling you wrong on this one thunder..

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Where you getting internal chip loss at?? Your return level out the tap is going to be determined by 2 things... 1. The value of the tap. 2. The pad that's in the LE..

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The return output pad size is determined by the total return loss; cable loss, return insertion loss on passives etc. to ensure unity gain on the return path from active to next upstream active or "0" gain. If you trace the return path from the combined output (the forward output diplexer of an active) back thru the return you will hit the return amp chip(ours are 12dB) before the return output pad which again is used to ensure "0" gain to the next active upstream. Therefore if all is properly balanced upstream your Tx at an LE for example would be the amp chip plus the test point of LE/ or whatever Tap size. Amps have internal coupling/ splitters etc which factor differently but still the chip is counted. BTW you only subtract the chip value if determining Telemetry inversely from your injection level, otherwise you do add it to TP or Tap size if it's simply an LE/no other internal splits or combining etc. That's just how we does it. Maybe my english not so good sometime!! [img]http://www.line-man.com/forums/public/style_emoticons/default/mf_laughbounce.gif[/img] Edited by Thunderstruck

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[quote name='System Tech Senior' date='07 October 2010 - 06:00 PM' timestamp='1286499652' post='143095']
Got anything else Jonathan???
[/quote]

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[media]http://www.youtube.com/watch?v=AuOM2f096LQ[/media]

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#45
[i]What are you talking about You have a tap that will adjust the return aside from the foward???

Post a picture
olo131[/i]

Mayby I missed the info about these taps. (in that long topic).

But I noticed this recent contribution/forum:
[url="http://www.line-man.com/forums/index.php/topic/24869-cisco-multimedia-stretch-tap-directional-coupler-with-reverse-window/page__hl__%2Breverse+%2Bwindow+%2Btap__fromsearch__1"]http://www.line-man.com/forums/index.php/topic/24869-cisco-multimedia-stretch-tap-directional-coupler-with-reverse-window/page__hl__%2Breverse+%2Bwindow+%2Btap__fromsearch__1[/url]

"Google search"

[url="http://www.cisco.com/en/US/prod/collateral/video/ps8806/ps9075/ps9076/product_data_sheet0900aecd806c7a31.pdf"]http://www.cisco.com/en/US/prod/collateral/video/ps8806/ps9075/ps9076/product_data_sheet0900aecd806c7a31.pdf[/url]

[url="http://www.cisco.com/en/US/prod/collateral/video/ps8806/ps9075/ps9091/7022397.pdf"]http://www.cisco.com/en/US/prod/collateral/video/ps8806/ps9075/ps9091/7022397.pdf[/url]

73 Willy.

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what is DOC 3.0???

lmao i kid i kid, we are still 1.1 here. we offer 7dn .05 up lmao
but some of our modems are wide open and we can get about 20-25mg dn 2-3up

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You let your modems run wide open on a 1.1 system?

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[url="http://www.speedtest.net/result/2170450467.png"]http://www.speedtest.../2170450467.png[/url]


My (test) modem at home :) that is one of advantage when you are employed in cable company.


Docsis 3.0

"KOPERNIKUS" Cable Company, Serbia

We are offering speed from 3/0,5 Mbit/s to 50/2 Mbit/s. Four channel bonding in downstream and two (on some place four) channel bonding in upstream. In this year, we are gonna bond everywhere four channel in upstream.

But here, in Serbia we are using Eurodocsis an that give us a lot of free space in return path (5-65 Mhz) in comparation with Docsis (5-42)... Edited by jetsetwily
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I can hit 275 down/ 40-50up on my modem here when I want to (8x2, package set to 320/120), but I find the wide open seem to lag a bit in online games, so I usually have mine set to our 50/10 package (I never use all that anyway), the config probably needs tweaked, but then, I don't expect we'll be selling that 300meg speed anytime soon.

Because of the way D3 works, you have to run the test a few times to force the modem to open up a bit.


Also, I might note, this stems from my problem with my Trilithic meter: If you're running a Cisco CMTS, and you have 8-channel bonding in place - 4-channel modems [b][i]will not bond at all.[/i][/b] So far, every 4-channel modem I've encountered has failed to bond. Its a problem with the CMTS software it seems. (sending incorrect rcp messages) If I set the CMTS wideband interface back to 4, the 4-channel modem locks right on. So, needless to say, we're only buying 8x4 modems here.

Arris did actually have a workaround for this in their firmware, but it seems motorola and hitron (makers of the trilithic modems) have not clued into this - afaik at this time. If CISCO would fix their CMTS software, that would be the more correct thing to happen, but has anyone tried talking to cisco lately? Theres no way to get to anyone with brains. (or it seems very difficult, anyway) Edited by Capm
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Capm, thanks for info about 8 channel bonding and problem with 4+4 modems. We are using CISCO, and will keep that in mind.

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