Re: CW narrow filter
Joe Subich, W4TV
If you find you really need one, I'd suggest the 200 Hz filter, because the 250 Hz filter is actually not all that much narrower
I would choose to believe the measurements made by Elecraft at:
The Elecraft curves show the -6 dB response points at roughly 480 Hz
for the "400 Hz" filter (KFL3C-400) and 370 Hz for the "250 Hz" filter
(KFL3A-250) both of which are actually made for/imported by INRAD.
The Elecraft application note also includes a comparison of the
KLF3A-250 vs. KFL3C-200 which shows the 200 Hz filter is tighter
than the 250 Hz filter to at least -50 dB (where the bandwidth
of both is approximately 700 Hz).
... Joe, W4TV
On 2018-11-26 11:53 AM, ve3ki wrote:
To start with, try just using the Width and Shift controls. You can narrow the DSP bandpass down to 50 Hz, independently of what roofing filters you may or may not have installed. See <http://www.nccc.cc/archived_meetings/pdf/K3%20Filters,%20Jan%202009.pdf>.