[Elecraft] Lazy poor man's Skimmer

[Kjeld Holm]

Dear Elecrafters

I am the fortunate owner of a K3 100 with subreceiver and 13kHz, 2.8kHz,
1.8kHz, 400Hz and 200Hz roofing filters.

My wish is to use Skimmer to monitor as much as possible from 3.500 to
3.525kHz for CW signals. But I am not ready for the economic and practical
challenges of using P3 or a SDR radio. 

My plan was to use my 13kHz FM filter to receive CW but that seems not to be
"allowed". That is what K3 Util tells me when I try to enable the 13kHz for
CW reception. 

Any suggestions?

Or is it just plain impossible?

Vy 73 de OZ1CCM, Kjeld