User Manual

WiNRADiO G3XX User’s Manual

IF Shift and Passband Tuning

Dragging the centre red line of the filter passband does not result in the

bandwidth change, but rather moves the entire passband. Such IF Shift

makes it possible to tune the receiver to where the actual signal is, by

positioning the IF filter passband precisely over the real-time signal spectrum.

To use this feature, drag the red vertical line in the middle of the highlighted

filter passband anywhere over a signal peak within the displayed real-time

spectrum. Alternatively, you can use the IF Shift control either by typing the

IF Shift value manually, or using the up/down arrow buttons, or the small slider

between the two buttons: Place the mouse cursor on it and see the cursor

shape change, to indicate a ‘slider’ type of control. To change the IF Shift

value, hold down the left mouse button to drag the slider up or down. To reset

the value back to zero, press the associated Res button.

Note that for the USB and LSB modes, only one of the two filter edges can be

dragged with the mouse. The other edge, which represents the imaginary

“carrier” frequency of the station remains stationary. IF shift is again

accomplished by dragging the centre line. The inactive filter edge is shown in a

darker color.

The IF Shift facility makes it possible to quickly and visually tune to another

station represented by a signal peak in the real-time spectrum. However, it is

not very suitable in the AMS, USB, LSB, DSB and ISB modes if you only wish

to adjust the filter passband position slightly for the station you are currently

receving (for example to avoid interference from an adjacent channel). If you

do this, and are, for example, tuned to an AM station using the AMS mode, or

an SSB station using the USB or LSB modes, then moving away from the

exact carrier frequency will result in a whistle being heard, its pitch being

directly proportional to the IF Shift displacement.

To make it possible to move the filter passband only, but still remain tuned to

the same frequency, there is also an associated Passband Tuning mode:

This is invoked by dragging the graphical centre of the filter passband with the

right mouse button instead of the left one. This makes it possible to finely

adjust the filter position in the AMS, LSB, USB, DSB, ISB or CW modes,

without the whistle effect. Note that in this mode (indicated by “PBT” displayed

in the filter passband) it is not possible to move the filter passband to another

station - simply revert to the normal IF shift mode using the left mouse button

or the IF Shift control, or press the Res button, if you need to move to another

station peak.