Jaggy Taggy wrote:
Who decides to which side of the carrier the BFO will heterodyne a CW
signal.
I mean there must be convention, otherwise we would have to find out on an
individual basis, but what is this convention???

A BFO will heterodyne a signal on *both* sides of the carrier. Most
modern receivers are designed to filter out the heterodyne on one side.
For CW signals, which side depends on the manufacturer. (i.e. there
is no convention!)
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com