[Elecraft] Filters and Spectrum Analyzer.

[Jack Smith]

I should add another option would be to use an outboard mixer and signal 
generator and create a mirror image of the K2's internal process.

Tracking Generator --> MIXER --> to K2

Mixer LO driven from a signal generator set to provide the correct 
offset and frequency inversion.

Adds a bit of complexity to the equation, but should work.

Jack