Very poor ADS-B reception

As both dongles (FA & NooElec) failed to receive 1090 Mhz, and as your wide band (24 mhz to 1800 mhz) scan by Spektrum shows that interference was removed completely by filter, the most likely reason is that your JetVison antenna has gone bad, may be due to ingress of moiusture.

If you can make a temporary 1/4 wavelength DIY antenna, diconnect coax from JetVision antenna and conectc coax to this temporary DIY antenna, it will make things clear.

You can initially try this DIY antenna indoors near a window before mounting it besides the JetVision antenna and diverting coax from JetVision to DIY.

(1) QUICK SPIDER - No Soldering, No Connector