The other night I noticed that I was missing a number of very weak CW stations while scanning the bands outside of the ham bands with my FT817ND...
I had just built up a 4 pole cw filter for 750Hz and tried something...
I use an external speaker on this rig when not in the field so I tried using the CW filter along with standard audio output (running a small 386 amp for the CW filter of course) well well... I works very good... not only can I hear the phone stuff but also the CW signals that are just at the noise level... like the CW stations very close to the SW broadcast stations... I was surprised to here all that CW action down in the 11-14 Mhz region that I was missing. And dummy me was only using the CW filter in the ham bands...!!! (kicking myself) arrrggghhhh!
A bit of history>>> This is very much like the old lash up I used to use with my tube rigs... kinda sorta... I had those beasts set up with seperate detectors for each type of emissions... ie: AM, NBFM, CW, SSB... very noisy because they were fed to their own amplifiers but it was fun and worked very well...
BTW You can kinda sorta customize the audio on the FT-817ND but putting different values of filter capacitors ( 10 - 100 ufd ) across the speaker leads... cheap and dirty sure but it does help lower the awful atmospheric noise... not to mention the really bad hash from the AC lines out here. If you like try it on your rig I am sure it will work on other rigs because most of these newer rigs use OP amps as the output stage. Worth a try...

later all...