since the Flex6700 has two separate A/D's to Phase and Amplitude adjust Interference out
see youtube video
MFJ has a similar unit. It requires two antennas. The big "IF" of the success of this technique is that one antenna should be subjected to a higher noise than the second antenna. This gives the unit enough information to discern between wanted and unwanted signals. If Flex were to implement this it might cause more problems than it solves in that meeting the conditions of subjecting one antenna to the noise source more than another could be problematic and cause more complaints than praises.
73 DE EA3HSO
Here's a link to a badly shot video of an ANC-4 demo at the shack.
Signals keep almost the same, noise dissapears.