Recently Tom Rondeau did a bunch of work to add message passing support to GNU Radio’s Qt based plotters. This is really cool because now there’s not a whole lot of need for the gr-pyqt (pyqwt based) message plotters anymore other than prototyping custom plotting things. The obvious thing to do was update Such Samples to switch over to the more efficient, portable, stable, feature filled, and well supported plotters from the main GNU Radio distribution.
Building the Graph
Now that the Qt Gui message plotters have complex PDU message port input, we can simply hook them up to the pyqt file message source and everything works as expected! To make wandering around recordings easier, there is now an open dialog which passes messages into the message source, and a drop down for file type would be nice to add too. Overall the flowgraph is super simple and all message based, shown below.
Running the graph, the new plotters look quite a bit cleaner and better than the old ones! The spectrogram/waterfall plot now supports messages as well, so we include that in addition to the time/frequency plots. Below you can see a wideband look at the 2.4 GHz ISM band which can be easily explored and intuited in each plot dimension.
This flowgraph is available on github @ such_samples2.grc