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 
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
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 . PGA reports this observation will
require 580 seconds OTT.