Second, for the purposes of this exercise, the winds do not  have any significant speed changes. Prior to starting the plot, a scale depicting the wind speed  must be established. In this example illustrated, two squares  on the graph paper will represent a wind speed of 5 miles per  hour (mph). In the absence of a wind meter, or other accurate  wind reading, a rough estimate of the wind speed may be  made using the technique shown in  Figure 3-5 .  At 1 minute, take a second reading. The pibal will be at  approximately 300 feet AGL. In this example, the reading  take n is 310°. Using the plotter, draw a line 10° off the  origi nal azimuth (the A-B line), and make another mark  appr oximately two squares away from the mark labeled  “B.” For clarity, this is be labeled “C”. See the example in  F igur e 3-7.  (NOTE: The angles in the successive graphics  are exaggerated for clarity.) To begin plotting the pibal recording information, release the  pibal and track it with the compass. After 30 seconds, take  a reading and make a mark on the graph paper to represent  the start point. Make a second mark to represent the direction  plotted. In  Figure 3-6,  a track of 300° at 5 mph is depicted.  Label the first two points “A” and “B.”  [Figure 3-6] Figure 3-1B. Plotting your course. At  1:30 minutes, take another reading. The pibal will be at  appr oximately 450 feet. Using the plotter, draw a line 30° off  the  original azimuth (the A-B line), and make another mark  appr oximately two squares away from the mark labeled “C.”  This mark may be labeled “D” for clarity.  [Figure 3-8]  Wi nd s  m o r e t h a n 5 k t s . $_{ }$W $_{i}$n d s $_{l}$e s s t h a n 5 k ts. 0°  t o 4 5 ° $_{ }$4 5 ° t o 9 0 ° 2nd pibal reading 300 feet A B C 1st pibal reading 150 feet A B 3rd pibal reading 450 feet A B C D $_{Figure 3-5.}$ A  method for determining wind speed. Figure 3-7.  Second pibal plot showing 310 °  at 1 minute. Figure 3-6.  First pibal plot showing 300 °  at 30 seconds. Figure 3-8.  Third pibal plot showing 330 °  at 1:30 minutes. 3-6