Figure 97.
Ideal and Very Poor Spectrums.
c. Now look at Part B of Figure 97 which shows a very poor spectrum. A
spectrum of this type indicates that the output of the magnetron is not a
good rectangular pulse.
If the output of the transmitter looks like the
spectrum shown in Part B or is distorted in some other way, it means the
magnetron is not operating correctly. An incorrect spectrum indicates one
of the following troubles:
(1) Magnetron pulling.
(2) Magnetron pushing.
(3) Mode shifting and mode jumping.
(4) Improper pulse width.
d. The spectrum analyzer is a quick means for checking the transmitter.
If the radar set is not operating correctly, a spectrum analysis lets you
know whether or not the cause of bad operation is in the transmitter. If it
is, the next step is to isolate the trouble to a particular stage and
component.
34. Final summary.
You have learned in this lesson how a magnetron works, and you have
seen some possible causes of magnetron troubles.
You realize now that
although the magnetron is basically simple, a radar set is useless unless
the magnetron is working.
Figure 98 lists the main characteristics and
operating values of four different magnetrons.
This shows at a glance
typical values you will work with. As part of the final summary, a glossary
of magnetron terms follows Figure 98.
Refer to the glossary until you
become familiar with these terms.
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