I’m doing in-house sweep & noise mitigation and we’ve always come across nodes that have a bit of ingress in 5-10 MHz band. Before they weren’t scrutinized just as long as the modems at 32 MHz were OK, and there was no CP, impulse/ electrical noise, and it wasn’t off the charts. Now that we’re using more bandwidth and are specs have tightened--It’s an issue. The really ****-hot spec-analyzer stays in the head end. We have to use the DSAM-6000 which can only find the blatantly obvious stuff.
I need to know: Specifically what’s causing this 5-10 MHz crap? (YES, I know it’s mostly from drops) How can I track it down locally—without constantly asking a tech in the Hub, “Is it gone yet?” Better yet, I need tips and tricks to find it off individual feeder legs without having to shut-down the return in the whole node, in cases where you have contributing junk off multiple legs coming back to the transmitter. I tried finding noisy TDR shots (or what my TDR would see as a “powered line”) using a riser-bond TDR, but I ended up chasing a phantom bleed-over from my own forward signal. Is there any cheap, effective methods to track/isolate this?
What are those 5-10 mhz return spikes?
Member #: 31005
Registered: 5/31/2004
Posted:
2
Name:
George
Company:
Adelphia
Occupation:
Technical Supervisor
Location:
WPB
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