Réception à conversion directe (SDR, Flex, ANAN, KX3...) et Sélectivité / intermodulations

I said nothing about the 6500 ... the reference was to the 6300 which
has no preselectors and sees the entire spectrum. In that regard it is
identical to the Elad FDM-DUOr that NC0B found was heavily impacted by
a half dozen strong AM signals even at his rural QTH 35+ miles from
the nearest of the stations. Those half dozen or so signals caused an
S9+10dB IMD noise level in the receiver.

Again, direct sampling SDR technology can not provide the strong signal
handling necessary to provide spurious free operation while providing
sensitivity down to -135 dBm or so with the present technology. The
ADC used needs another 20 dB of headroom or the input bandwidth needs
to be restricted to prevent the aggregate signal level from exceeding
the clipping threshold.

While a good BCB reject filter will accomplish much for many users,
there are still plenty of places - those with active neighbors, users
in high RF areas (e.g., 40 meters in Europe) - that will experience
significant problems due to ADC clipping.

73,

... Joe, W4TV