QT waterfall sink manual intensity

GNU Radio
1

Is there way to manually scale the intensity of the QT waterfall sink,
in other words, set the dynamic range and reference level like the WX
sink?

Adjusting the time axis with the scroll wheel alters the intensity axis,
but the actual color values don’t change.

Thanks,
Lou
KD4HSO

2

On Mon, Feb 24, 2014 at 10:38 PM, Louis B. [email protected]
wrote:

Is there way to manually scale the intensity of the QT waterfall sink, in other
words, set the dynamic range and reference level like the WX sink?

Adjusting the time axis with the scroll wheel alters the intensity axis, but the
actual color values don’t change.

Thanks,
Lou
KD4HSO

Just to make sure, are you using the QTGUI “sink” (the one with tabs
for the different types of plots) or the “waterfall sink” (with /just/
the waterfall). If the former, there should be two bars for the upper
and lower intensities that will affect the colors.

If using the waterfall plot directly, we haven’t instrumented the
min/max from the gui directly (to avoid clutter). However, the object
does export the set_intensity_range(double min, double max) that you
can use to directly control these.

Alternatively, with this plot, if you middle-click on the mouse, the
drop-down menu offers an Auto Scale feature that will adjust the
dynamic range based on the min/max values in the current plot. I’ve
found that to be the most useful way to control the intensity.

Tom

3

I’m using just the waterfall sink. The spectrum is slightly oversampled
so I see the decimation filter roll off to -170 dB and the edges, thus
I’d like to set the intensity minimum at the passband noise floor which
is up at -100 dB. The auto scale always catches -170 dB at the edges.

I’ll try editing the Python script directly to access the
set_intensity_range(double min, double max) of the object, unless there
is a way to do it in GRC.

Thanks,
Lou
KD4HSO