The return pulse is spread out over a few hundred microseconds in time,
due to the curved surface of the planet.  A series of five windows will
appear on your screen when the pulse is received.  These windows show
"snapshots" of the pulse shape beginning at the instant of reception,
followed by another 120 microseconds later, and three more at successive
90 microsecond intervals.  These pulse images show a certain amount of
noise, which increases with the later-arriving pulses.  Compare the
appearance of the received pulse with the initial pulse.

Clicking the cursor on any visible portion of a data window will bring
that window to the "top" for observation and measurement.  Clicking the
down arrow in the upper left corner will reduce the window to an icon.
An iconized window can be redisplayed by double clicking on it.  A popup
menu under "Pulse" on the main menu provides for reducing and displaying
all the data windows at once, as well as recording measurements made on
the pulse profiles.  Data windows cannot be closed (unless a new radar
pulse is transmitted), so that they can always be remeasured, if
necessary.

To make a measurement, simply press and hold the left mouse button and
move the cursor to the point to be measured.  When the button is down
the cursor becomes a cross-hair, and the lateral position of the mouse
appears at the bottom of the screen as an X coordinate (measured in
pixels), and a frequency shift in Hz from the zero position.  You must
measure the positions of the left and right "shoulders" of the plots,
the points where the intensity just begins to fall off to zero.  On
some of the plots these points are quite obvious and on others they are
not.

When you have positioned the vertical cross-hair on the left "shoulder"
of the plot, double click the left mouse button.  A red arrow will
appear on the screen, along with the measured position in Hz.  To measure
the right "shoulder", follow the same procedure.  A blue arrow will
appear at the measured position .  (The single pulse on the t=0 window
may be measured by the same technique.)  If you want to change a
measurement, simply reposition the mouse and again double click the
left mouse button.  The associated arrow will move to the new location.

After you have measured a pulse window (or all of them), select "Record
Measurements" under "Pulse" on the main menu.  A data window will appear
recording all the measurements you have made.  If you have not measured
all the pulses, the remaining fields on the measurement window will be
blank, and the next unmeasured pulse window will apear on top.  If you
have completed all the measurements, a message will inform you of this,
and the pulse windows will be minimized when you respond to the message.


