You may get better or worse image rejection than this (depending on your particular combination
of component tolerances) and toroid winding style. This is not normally something to worry about.
However if you have a significantly worse image rejection then it is time to start debugging your
unit; most likely is a problem in the area of the trifilar transformer. Faults such as incorrect wiring
(wires in the wrong holes), a broken wire, shorts between wires, etc., can all cause this.
In this annotated
image, the four
audio responses
are identified; all
four appear in the
receivers audio
passband. When
everything is
correct, the three
unwanted ones
(the lower
sideband and the
USB/LSB at the
image frequency)
are at a much
lower signal level
than the wanted
in-channel USB
reception.
QMX operang manual; rmware 1_00_012 70
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