In Reply to message #372148 by Linedogs
Member Member aclementsiv is not online, or is invisible.
1/21/2017 1:33:57 AM
aclementsiv Member #: 92828 Registered: 5/12/2013
Posted: 11 View all posts by aclementsiv
Company: Charter Occupation: System tech Location: Michigan
Re: Over equalizing return addition
If you don't have them already, chances are you will have a cable modem upstream in that range. Purposely over eqing to fix noise will cause your transmit levels in that range to be much higher than on other upstream channels. With unity gain on the upstream the point is to hit your cmts at 0 at your modem center frequency. If you have even a little extra eq, say 1.5db across your return bandwidth, and you try to utilize those lower frequencies, your modems will be hitting lower than 0 which will affect your carrier to noise level, modem tx levels and the inherent tilt in the return will affect in channel frequency response and cause the modems to work harder to hit the cmts with a clean flat signal. If you are running docsis 2.0 or higher with 64qam upstreams, look into pre equalization and you will see what I mean.  I hate to sound like a jerk, but instead of eqing to comp for noise, you are going to be way better off in the long run just tracking and fixing the noise. Besides, most noise in the low end of the return spectrum is coming from houses anyway. Give those service techs something to do... I am willing to bet everyone else on here will agree. Fix the noise, don't try and hide it. 
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1/23/2017 2:00:27 PM
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