Michael van Hauten wrote: >Dear K2-friends, >is it good to have DSP and NB or is DSP alone able to filter all the dust coming through the air? > I'd say both. The NB is especially good for certain types of noise (e.g., from ignitions or electrical motors or power lines). At my QTH the KDSP2 is the more useful of the two, but it cannot beat the KNB2 in some situations. Phil