Two examples will be worked through.
1. An observer want to observe a source of strength 2 Jy between 40.5 and
41.5 
m, reaching a S/N of 30. This wavelength range corresponds to 50
scanner steps. From figure 6.4 we see that we reach a S/N
of 20 on a 6 Jy source in 2500 seconds while scanning 100 steps. Therefore to
reach 2 Jy with 50 steps will take 
seconds. PGA reports this observation will require 23600 seconds OTT.
2. An observer wants to observe a source of strength 10 Jy between 25 and
26.25 m (100 scanner steps) and reach a S/N of 40. From figure
6.4 we see that we reach a S/N of 20 on a 1.5 Jy source in
2500 seconds while scanning 100 steps. Therefore our observation will require
seconds. However, the minimum observation time
is 420 seconds from table 6.7. PGA reports this observation will
require 580 seconds OTT.