Prevents Shortwave Interference: This filter is primarily used to filter out FM signals, preventing their interference with shortwave frequencies, which significantly improves communication system performance. Rejects 88-108 MHz Signals: This filter effectively suppresses signals between 88-108 MHz with an attenuation of approximately 50dB or more. Impact on Aviation Frequencies: This filter also affects aviation frequencies. You can observe this if you see an image of a BCFM station when increasing gain, appearing as interference from WFM signals on other frequencies. Useful with SDR: FM broadcast band blocking filters are highly beneficial with SDRs, especially in regions where FM broadcast signals are strong and cause overload. This overload can lead to very poor performance in other frequency bands. Equipped with Bidirectional Interface: The FM band-stop filter features a bidirectional interface, allowing for the suppression of signal interference caused by aviation frequencies.