[Elecraft] 1 Khz filter

[Jim Brown]

On 7/25/2017 7:11 PM, Bill Breeden wrote:
> I found that I was missing stations that were calling on the skirts of 
> my 400 Hz filter, so I added a 1 kHz filter.  When I tune the band to 
> answer CQs I still prefer listen through the 400 Hz filter. 

It's important to remember that IF bandwidth is determined by DSP, and 
continuously adjustable. The plug-in filters are ROOFING filters -- 
their primary function is to protect the DSP from overload by very 
strong stations outside the bandwidth of the DSP IF. They have the 
secondary function of adding the filtering provided by the DSP, and when 
the DSP and the roofing filter are at the same bandwidth, the filter 
skirts become steeper (sharper).

Bottom line -- we don't need to buy a 1 kHz filter to get 1 kHz IF 
bandwidth, because the DSP already provides that. This is not your 
grandfather's radio! :)

73, Jim K9YC