[RTTY] RTTY Rx filter bandwidth

[Ed Muns]

The KFLA-250 is nominally 370 Hz wide at the -6 dB points.

If SHIFT is needed to center the filter on the Mark/Space signals, then the
filter needs an offset in the CONFIG parameter.  Despite the claim that the
8-pole filters have zero offset, I've found a number that do.  This is
especially important on these narrow bandwidth filters.

Ed W0YK

Dave K6LL wrote:
> I use the 250 Hz roofing filter and DSP BW 350 as my go-to 
> RTTY settings on the K3.  It seems to work well for me.  Use 
> the SHIFT control to make sure the mark and space are 
> centrally spaced in the spectrum display.  The mark and space 
> should be just about the same amplitude as the center 
> amplitude, with the sidebands tailing off on both sides from there.