[Elecraft] [K3] Elecraft roofing filters

[Bill W4ZV]

ni0c wrote:
> 
> My testing was done in CW mode with the pitch in the 
> low 300's (320 Hz, as I recall).  So, when I repeat the tests,
> I'll vary the pitch and see what happens, say 300 Hz, 600 hz, 
> and 800 Hz.
> 

Another person who likes a low pitch!  This really affects what you will
hear because the MCU firmware shifts the bandpass so that the low end always
truncates at ~200 Hz.  If you use a nominal 500 Hz filter, this means it
will be positioned from 200-700 Hz, so you'll hear signals 400 Hz above your
zero beat frequency of 300.  This would be equivalent to an 800 Hz filter if
centered.  The K3 operates differently from Orion which I know you had
before.  This is exactly why I sold my 1000 Hz filter.  With a nominal
bandwidth of 1100 Hz and 300 Hz PITCH, I was hearing signals 1 kHz above my
zero beat QRG (i.e. my actual bandpass was 200-1300 Hz).  1 kHz above my QRG
is not practical on any sort of crowded band.  If the band is not crowded
with strong signals then the stock 2.7k filter is about as effective.

73,  Bill

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