[Elecraft] KDSP2 sound vs the KAF2

[Lyle Johnson]

Hello Vic!

> Unfortunately this doesn't work on CW.  The maximum bandwidth in the CW
> mode appears to be 800 Hz, which is what I have my C2 filter set to.  I
> would like to have a C1 filter with a b/w of about 2 KHz for use as a
> hiss filter, but I haven't been able to figure out how to do this.

It won't happen anytime soon, I'm afraid.

Here's why.

The KDSP2 MCU has limited program memory, and it is all used.  Every byte.

To make things work in a consistent manner, I had to set up the filter
selection menus as a 16x16 array.  So there are 16 center frequencies and 16
widths available on a mode-by-mode basis (SSB/CW sharp/CW soft/Data).

Within these limits, we tried a number of things in Field Test.  The LPASS
special function was added so folks could listen to a wide swath of the band
no matter what the mode.

Now, I could make the LPASS CW soft and LPASS CW sharp filters different,
and put a cutoff of the sharp filter to, say 2 kHz or so.  To see what that
might sound like, you can go to SSB mode (Ok LSB if you are a CW guy :-) and
adjust the filter wo that you think is best.

(If enough folks try this, and AGREE on what would make a good alternate, I
*may* update the Flash to do this.  But I promise nothing!  :-)

But in BYPASS mode, you'll still hear the whole bandwidth of the radio.

Apart from that, I can't see much opportunity to change things without a
wholseale change to the code -- which path is fraught with peril!

73,

Lyle KK7P