Hi,
Assuming we’re talking about station 223.
I skimmed through the earlier conversation: strange-waterfall-on-vhf-satellites-uhf-is-fine
There’s a few ways this can happen, I’m not sure which of them you have investigated already.
A block diagram of the station hardware would be helpful as well.
Do you have access to a spectrum analyzer? looking at the signals with a wide bandwidth and high reference level can show if there’s very strong out of band signals that can make the sdr deaf.
Hooking a amateur rig to the antennas, do you get any signals ?