u/Which-Telephone-7751

Trying to help troubleshoot a satellite-over-fiber setup that isn't passing signal, and I want to make sure I'm asking the right questions before escalating.

The setup runs the satellite L-band signal from the dish over a fiber optic link. There's a transmitter at the dish end and a receiver at the other end, feeding into a satellite receiver. The fiber receiver unit is powered up and showing a steady green light, so on the surface everything looks healthy on the link itself.

The problem is that despite the green light on the fiber link, the satellite receiver downstream is showing error 775 and no usable signal is getting through. As I understand it, 775 means the receiver can't communicate with / get power out to the dish's LNB, so it points to a powering or signal-path problem rather than the receiver itself being dead. The green light on the fiber unit only tells me it has power and an optical connection. It doesn't confirm the right signal is actually present on the line, since these links just pass whatever RF they're given within their frequency range. So a healthy-looking link can still be carrying nothing usable.

A few things I'm trying to rule out:

• Whether the LNB at the dish is actually getting enough power to operate (which would explain the 775)
• Whether the frequency coming off the dish is within the range the fiber link can carry
• Whether the issue is upstream at the dish/LNB or downstream at the receiver
• Whether the optical signal level reaching the receiver end is within spec

What I'd like input on: when the fiber link shows a normal green/powered state but the satellite receiver reports error 775 and won't lock, where do you usually find the fault? Is this typically a powering problem at the dish, a frequency/compatibility mismatch, or something on the optical side?

Any pointers on how to isolate it would help. Thanks in advance.