Many handie-talky radios suffer from severe interference from nearby transmitters, particularly on hilltop sites. Blocking is a reduction in sensitivity that can be hard to detect. When a radio is being blocked all callers (even strong ones) can appear weak or may even be undetectable.

The SOTABEAMS bandpass filter is a small, rugged and lightweight filter that eliminates virtually all interference problems. The filter is a helical design that is made especially for SOTABEAMS. It is simply attached between the radio and antenna.

More Information - https://www.sotabeams.co.uk/bandpass-filter-for-2m/