In Reply to message #365786 by ndunnski
Journeyman Member jdahl1979 is not online, or is invisible.
2/17/2015 12:24:02 AM
jdahl1979 Member #: 46318 Registered: 5/18/2006
Posted: 100 View all posts by jdahl1979
Company: Time Warner Cable Occupation: Maintenance Tech Location: NC
Re: elevated noise floor
The reverse input levels are very low for noise.  Sometimes you might see the thermal noise before the actual noise floor on some testpoints.  What type of actives do you use in your area?  What is you typical first tap off LE's and what is the TX? Your devices probably hit the input somewhere between 12db to 17db depending on your design.  If you look at the same reading on the output, you could be talking about a difference up to 20db. You might have impulse noise that is faster than the analyzer in your meter and max hold only tells you part of the story.  It's better to get an unequalized MER of your CMTS input if you can and try to improve the MER as you go.  Even getting the US SNR of a modem in the same node or US port will tell you more than most meters unless you have Pathtrak, SST's or addressable analyzers that you can interface with via the web.  What type off meter do you use?  I might have some settings to help with noise or I'm sure someone else around here does.  I have some other questions/answers but I need more info on your particular system.
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2/17/2015 1:37:11 PM
ndunnski