RTL-SDR.com Broadcast FM Band-Stop Filter - TechnoFix UK
I bought a cheap FM bandstop filter and measured it using a unreasonably expensive R&S Spectrum Analyzer. The bandstop seems pretty good for the price. : r/RTLSDR
Amazon.com: Flamingo+ FM - Broadcast FM Bandstop Filter v2 (FM Notch Filter) for Software Defined Radio (RTL-SDR) Applications. Blocks Problematic 88-108MHz Frequencies from Your SMA-Connected Radio : Electronics