(2) The 40-mile range consists of eight intensified rings, each
representing 5 miles, on the time base sweep called range marks
(a) Adjusting the PPI GATE LENGTH control R1511 will cause the
time base sweep to lengthen or shorten.
As the time base sweep is
shortened, the number of range marks will decrease and; as it is
lengthened, the number of range marks will increase.
(b) Rotate the PPI GATE LENGTH control R1511 slightly clockwise
and then counterclockwise and observe the PPI display (Figure 51).