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Triggered plots


When the 'Triggered' checkbox is selected, PolarPlot will only take a reading when either an external trigger pulse is received from pin 8 (CTS) of the specified 9-pin serial port or when the Manual Trigger button is clicked.  This mode is intended for high accuracy plots and a precision rotator is required if best use is to be made of the facility.

a) Disable auto start and auto stop by clicking in the appropriate checkboxes. 

b) Without altering any of the gain settings, the beam to be measured should then be turned to one end of the rotator travel.
 
c) If not already transmitting, start transmission.

d) Send a trigger pulse or click the Manual Trigger button to take a reading

e) Position the antenna to the next desired position

f) Repeat d) through f) until all desired readings have been taken

g) Stop transmission

h) If less than 360 readings were taken then click Halt Collection

At the conclusion of the plotting run the readings taken will be shown as a series of dots on the plot. Click the 'Rescale' button to produce the plot.

With triggered plots you have precise control over the number of readings taken, and the ability to position your antenna wherever you desire for each reading.  It does not necessarily follow that you have plotted 360 degrees of rotation - you may have plotted only 90 degrees with each point at 1/4 of a degree.  In such cases a circular plot will not be much use, though a rectangular one will.