Try optimising the gain
See this thread ads-b-flight-tracking-f21/gain-adjustment-t37172.html
The comments regarding the connectors were that they were secure, not well made.
Also, that SMA, not SMA-RP, connectors are used.
We have seen professionally made cables fall apart.
I left out a filter(not FA but effectively the same thing) on one setup a few weeks ago. Went from 150-200 aircraft to 2.
It is also possible that there isn’t much noise in your area.