There are many possibilities that may cause this but without being there it is difficult to give a exact answer.
Since it is across the entire spectrum (forward and return), it sounds like a DC voltage or grounding problem at first guess.
My suggestion would be to ISOLATE what you know IS good. I assume you are using a spectrum analyzer looking at the RF spectrum to view these beats. First off, power up the node having the forward fiber disconnected and confirm that the optical transmitter is not introducing unwanted carriers or noise into the node receiver while looking at the analyzer. If you have the beats generated with the forward fiber disconnected, it very possibly being generated at the node.
Another possibility is that you have EXCESSIVE light input to the optical receiver causing clipping and high RF output producing severe distortions. If the RF output is excessive, the diplex filters may not isolate or reject carriers as their manufacturers specifications have been exceeded.
You mentioned that you used different 120v outlets. Did you use a volt-meter and confirm that it is wired correctly? Confirm that you do not have a poor neutral or bad ground.
Give me a call on my cellular and we can talk. Possibly I might be able to help.
Good luck!
Greg Tobin
Interactive Broadband Technical Services, LLC
314-422-4423 cellular
Re: Here's One For You
Member #: 7190
Registered: 1996-2001
Posted:
483
Name:
Greg Tobin
Name:
Greg Tobin
Company:
Interactive Broadband Technical Services
Occupation:
HFC Engineer/Consultant
Location:
www.interactive-broadband.com
Personal:
Experience:
~45 years
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