About the Culgoora HF spectrum display

The display consists of the current real time HF Spectrograph image. As you move the mouse around the image you will see vertical and horizontal slices of the spectrum. The y axis is frequency and the x axis is time. to produce this display a spectrum analyser at Culgoora Observatory sweeps the HF spectrum every 3 seconds. The data is then sent to the Australian Space Forecast Centre in real time.

Threshold Scrollbar:

The threshold scrollbar will apply amplitude thresholding to the image from the value 20 to 200. Amlitudes below the set value will be set to zero, this will be shown in the frequency and time slice plots.

Why is it done?

Short wave fadeouts associated with solar flares can disrupt HF communications. Fadeouts will appear as a dip or bay in the horizontal slice plot. In addition the display shows the general HF environment at Culgoora. Bursts and noise spikes (both natural eg from lightning and man made), occupied channels (both sky wave and ground wave). Noise spikes appear as vertical lines of emmission, occupied channels are visible in the display as lines of increased amplitude across the image.