FM notch filters are used to reject strong FM signals. A good FM Notch filter will reject FM signals and have low insertion loss for signals outside the band.
Strong FM signals are everywhere as it's a universal broadcast technology used from 88-108 MHz. Lately the popularity of devices with FM modulation in the same band has increased. We can now find FM devices being used for localized audio broadcasts up to 15 miles. Needless to say these signals can saturate a receiver very easily. If a receiver is saturated it will not be able to pick up signals in other bands for which it was designed. An FM notch filter can prevent receiver saturation.
If you are looking for a FM notch filter that is optimized for the Airband Frequencies 118-138 MHz then try this one.
Frequency (MHz) Typical Attenuation (dB)
In Japan the FM band extends from 76 to 95 MHz while in North America it spans 88 to 108 MHz.
NOTE: Connectors are SMA-F