Sometimes the original readings collected, for one reason or another, jump up and down a bit. Noise on the signal, or wind blowing the antenna can result in irregular readings.
In an attempt to produce a smoother looking plot, a smoothing facility is provided. It must be stressed that your main objective should be to get a smooth plot in the first place, and that this facility should only be used as a last resort. To remove large 'spikes' from an otherwise smooth looking plot, use the 'Despike' facility.
The smoothing routine performs an averaging process on the point being plotted by summing its value with the immediately preceding and immediately succeeding points. This rather rudimentary process is performed twice, and the resulting averaged values are then plotted.
You may click the 'Smooth' button as many times as you wish, but eventually you will see no change in the plot.