I've had issues with hum on the return, where a carrier injected at the node is measured at the headend reciever, and high hum readings are shown. It can cause bad USSNR with the cleanest of noise floors.
If you try this, be sure to use a freq. thats at least 3 mhz away from an upstream data channel. Any closer and it can give you false positive hum readings.
Most times, the transmitter, dc power pack or optical motherboards in the node are the culprit.
Check recommended output levels and optical input levels on your receivers, make sure you're running the correct levels. We'll pad our returns to hit the receivers between -4 and -8 dBm light, and adjust RF for 34dBmV (single CW) out of the Rx, while hitting the node port at 20dBmV. But thats our system, our equipment.
Good luck
Re: What do you do to improve snr.
Member #: 19319
Registered: 1996-2001
Posted:
143
Name:
Lorne
Company:
major MSO (3rd namechange in 5 years)
Occupation:
Lead System Tech
Location:
Virginia
Personal:
60-ish
Experience:
~31 years
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