[Elecraft] RE: PowerSDR/IF stage v0.91 Released

[Scott McClements]

On Nov 25, 2007 10:05 AM, John A. McCabe <johnamccabe at verizon.net> wrote:
> However, one possible problem
> that I am seeing with the new version is that the IF frequency offset is
> limited to a maximum of 20000 Hz and I believe that that Softrock for K3
> requires a 23000 Hz Offset (8215 K3 IF frequency minus 8192 the softrock
> frequency).
John,

I never noticed that the crystal that comes with Softrock for the K3
was so far off. The 20000Hz limit is just in the dialog validation
code, I just changed it to 96000Hz, and the DttSP code seems to have
no problem using a value more than 20000Hz.  Thank you for pointing
that out. If someone needs this code right away I will build a special
patch - please only ask if you intend to use it very soon.

That crystal choice is not ideal, especially if someone can only use a
48Khz sampling rate. This means on the panadapter you will basically
only see 48Khz of band above the frequency you are tuned to. If you
are able to use a 96Khz sampling rate you will see 24Khz below and
73Khz above. I understand Tony, KB9YIG, only buys the readily
available crystal values to avoid the high cost of getting a custom
crystal frequency made.

-Scott, WU2X
http://www.wu2x.com/sdr.html