I realize that SDR provides more than one way to view the spectrum and
tune to a frequency, but I can imagine some people feeling comfortable
with a tuning knob similar to a traditional radio. There doesn't appear
to be any technical reason why a VFO knob could not be part of an SDR
application.
A quick Google search for USB VFO tuning knobs found these links:
http://df3cb.com/ft2000rc/documentation/interfaces/flexcontrol.php
http://www.eham.net/articles/21941
Has anybody tried anything like this with GNU Radio?
Regards,
Daniel