[Elecraft] 200 Hz 5-pole filter

[Jim Brown]

On Sun,7/26/2015 2:02 PM, Bill Breeden wrote:
> Since Sherwood's Dynamic Range Narrow Spaced measurement is of great 
> interest to CW operators, it only makes sense to make the measurement 
> using a CW filter, optional or not.  The measurement would be 
> meaningless to CW operators if made using the stock sideband filter.

Not really -- the K3, K3S, and KX3 IF filters are implemented in DSP. 
The plug-in filters are additional roofing filters that protect the DSP 
from overload by strong signals outside of their passband. The K3, K3S, 
and KX3 have very good CW receivers without the optional roofing 
filters. The roofing filters simply allow them to work very close to 
very strong signals, AND cascade with the DSP filter to provide 
additional rejection outside the passband.

73, Jim K9YC