Can anybody comment on what we are seeing in this picture that the australian broadcasting corp, what are the x and y and z axis]
Cloudbase4812,
It's a waterfall or cascade plot.
The x-axis in the bottom left is the frequency spectrum of the signal, the y-axis is time and the z-axis is the amplitude of individual frequency components. The latest spectrum is shown at the beginning of the plot and then it scrolls along the y-axis as a new spectrum is computed.
I cannot read the values of the x-axis, but it is probably 0-100 kHz, which is consistent with the orange peaks being at 37.5kHz. The y-axis display shows that discrete pulses are being received at regular intervals