Author Topic: JDSU DSAM  (Read 1058 times)

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JDSU DSAM
« on: November 19, 2011, 02:39:36 PM »
http://www.acternacablenet.com/dsamsim/


JDSU developed this DSAM operation simulator. It's a little difficult to sit thru more than a couple modules at a time... you'll find out why  :o
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Re: JDSU DSAM
« Reply #1 on: November 19, 2011, 03:25:08 PM »
http://www.acternacablenet.com/dsamsim/


JDSU developed this DSAM operation simulator. It's a little difficult to sit thru more than a couple modules at a time... you'll find out why  :o

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Re: JDSU DSAM
« Reply #2 on: November 19, 2011, 08:19:41 PM »
shit, I didn't get past the opening page. needs a next button to skip the audible portions lol
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Re: JDSU DSAM
« Reply #3 on: November 22, 2011, 07:55:23 PM »
Works just fine muted.  That's much better information than what comes in the operator's manual.  It didn't take me long to figure out how to turn it on, charge the battery, and keep the lens cover clean.  That was just about the extent of what they covered.
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Re: JDSU DSAM
« Reply #4 on: November 23, 2011, 06:25:28 PM »
That being said : Can anybody explain the Return Alignment function of this meter to me?  I think it shows the return across the amp, from ret. in to ret. out.   I suppose it lets you set the response of that active without seeing the rest of the return path back to the cmts.   Is there a benefit to this vs. using the return sweep?
      I'm trying to learn all I can about this meter, but JDSU isn't a lot of help when it comes to the fine details.
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Re: JDSU DSAM
« Reply #5 on: December 03, 2011, 04:24:11 PM »
Anybody?  Why do I hear crickets?  Was that a tumbleweed that just rolled by?  Help a brotha out here!
 
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Re: JDSU DSAM
« Reply #6 on: December 04, 2011, 01:50:25 PM »
My 2500 doesn't have this function (or very well hidden) and I'm guessing those with a meter that do have it don't ever use it or it wasn't purchased by the company.
I'm guessing it's like the constellation option... very rarely used when the level portion shows MER/BER errors much easier and faster... only really needed very few times in wtf situations.

"extent of what they covered?"
Perhaps they added pages after you posted.
7. Module 7: Taking Advanced Measurements
Pretty good read if this is the first time touching a DSAM.
You will find that most of these options are nice to have but you will only use 4 or 5 on a daily basis.
Please don't take that last remark negatively... knowing the extent of your tools capabilities is very good knowledge to have.

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Re: JDSU DSAM
« Reply #7 on: December 04, 2011, 04:07:01 PM »
The only functions I use are Tilt, Full Scan, Level, Return Sweep. Sweepless Sweep, and Return Spectrum.  I'm trying to convince the rest of the guys that miniscan is worthless and should never be used. Case in point :  Recently, I had a bad suckout in the middle of our digital tier.  Guy at the amp before me said it was beautiful there. Damn.... Bad cable between us.  Checked it at his amp, and itwas sucked out there too.  His miniscan showed good levels on the cardinal channels, but didn't show the channels in between.  I explained what he was missing. I drew three dots on a sheet of paper and explained that even though they only looked like dots, I could add more dots and make them into a picture of a pony. He was only seeing part of the pony.
 
    I'd like to learn all I can about this meter.  I did recently get my hands on a more in depth manual for it, and it's shedding a little more light on all this thing can do.
 
   
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Re: JDSU DSAM
« Reply #8 on: December 05, 2011, 11:07:37 PM »
I've had to ween the guys off using tilt, but miniscan can be useful when checking levels at an active if your not sweeping. We have a lot of older trunk (1"P3 and 1"MC2, 750P3 and 750MC2, some 825QR we tried) and newer is 875P3, and if not in good shape or bad splices/splitters/radial cracks under jacket/etc... you will see slight (or major) roll-off on the high end of your spectrum. Balancing amps/LE's to correct this is bad as it will cause overdrive in the amp module that will will throw Pres/Post the further you go down the cascade. The Pre/Post issue you see at the last amp may actually be starting at the first amp if the last guy used tilt to balance instead of looking at the fullscan. If you know what dB your mini-channels should be at the actives (you memorize them after the 100th time), then it's a little quicker to spot roll-off and backtrack and fix it.

I personally only use fullscan to check my forward channels and then single channel for AGC, check SNR, and then a Pre-Post check. Your system (and others) may not have as many roll-off issues as we do here as I haven't seen anyone else complain about it or just missed that thread completely.

There's a lot of good options on the DSAM (if your company purchased them), and you will find the ones  you like, but I believe you have already listed the ones you will use 99% of the time.

P.S.   Sorry about the hole in your pony

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Re: JDSU DSAM
« Reply #9 on: December 06, 2011, 05:58:31 AM »
Thanks, man. The pony's doing much better now.
 
    I check full scan at each amp first to get an idea of what the scan's doing. We have a bunch of MC2 and FD in our system. You're correct in your rolloff/ pre/post description. I see a lot of it here. 
 
     I hit FS, then go to tilt, then single channel for the agc.  Some of the guys never go beyond tilt and miniscan.  It screws things up and makes their jobs harder. If we miss something, it always comes back to bite us in the ass.
 
   I'm trying to sell them on reverse sweep, explaining that setting return on transmit levels alone is like balancing forward with ch. 60 and trusting that everything else will fall into place.
 
   Our company has tightened up so much on repeat maintenance calls. My supervisor catches the brunt of it and gets stressed. We catch his stress and try to make it better. As it stands, we not only have to make sure we clear the problem the service tech turned in, but everything else we can find.  It only makes sense to do that, but it cuts production down some. They'll be gigging us for that next.
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Re: JDSU DSAM
« Reply #10 on: December 06, 2011, 05:12:23 PM »
I've been so busy, I haven't had time to sit and write out a response regarding the Reverse Alignment function. Sorry Oldguy :duh:


The Reverse Alignment feature can only be used when the return sweep is possible, meaning the upstream for the node under test is connected to the input of the 5500 or 5510 unit in the headend/hub. You'll connect the meter in the same manner you would for return sweeping.


Are you familiar with the sweep function, and how to make meter connections in the field, at the node for instance?
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Re: JDSU DSAM
« Reply #11 on: December 07, 2011, 07:00:09 AM »
    Yes.  I've been using the reverse sweep, and saw that the telemetry had to be present to use the reverse alignment. I'm good with the connections.  What is the difference between the two?  I haven't done either in about two weeks becuase of vacation and projects.  My mind has been more on blacksmithing than cable for the last little while, and the technology leap is taking some time to readjust to.
 
    With the sweep, I realize that I'm looking at flatness across the spectrum with a center frequency.  With the alignment function, it appears that I'm looking at two frequencies on either end of the spectrum and seeing a comparison between what my meter is sending out and what is being recieved at the headend.  Am I on the right track?
    I'm guessing alignment could be used for equalization without really looking at overall response issues like the sweep function does. If so, I'd be better off using the sweep.
 
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Re: JDSU DSAM
« Reply #12 on: December 07, 2011, 05:00:06 PM »
Sounds like you have a good understanding of it already... It's just a tilt measurement for the return, to check for alignment to the headend sweep receiver. It might be best used when first optimizing the return at the node, to confirm your return levels before storing a reference.

and yes, your better off just using the sweep
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Re: JDSU DSAM
« Reply #13 on: December 07, 2011, 07:26:35 PM »
    That sounds reasonable. I usually inject back to the headend tech on 19 and 36mhz to check flatness and make sure the levels are correct at the reciever and CMTS.  I'll try using the reverse setup  next time and see what difference that makes.
 
    Thanks for your help. I really appreciate it.
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Re: JDSU DSAM
« Reply #14 on: January 26, 2012, 10:48:48 PM »
    That sounds reasonable. I usually inject back to the headend tech on 19 and 36mhz to check flatness and make sure the levels are correct at the reciever and CMTS.  I'll try using the reverse setup  next time and see what difference that makes.

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Re: JDSU DSAM
« Reply #14 on: January 26, 2012, 10:48:48 PM »