8-F-46: Equipment Faults-3
8-46F1:
Silicon crystals are used in RADAR mixer and detector stages. Using an ohmmeter, how might a crystal be checked to determine if it is functional?
Its resistance should be low in one direction and high in the opposite direction.
Its resistance should be the same in both directions.
Its resistance cannot be checked with a dc ohmmeter because the crystal acts as a rectifier.
It would be more appropriate to use a VTVM and measure the voltage drop across the crystal.
8-46F2:
In a RADAR unit, if the crystal mixer becomes defective, replace the:
The crystal and the TR tube.
Crystal only.
The crystal and the ATR tube.
The crystal and the klystron.
8-46F3:
An increase in magnetron current that coincides with a decrease in power output is an indication of what?
The external magnet weakening.
The pulse length decreasing.
A high SWR.
A high magnetron heater voltage.
8-46F4:
It is reported that the RADAR is not receiving small targets. The most likely causes are:
Magnetron, IF amplifier, or receiver tuning.
PFN, crystals, or processor memory.
Crystals, local oscillator tuning, or power supply.
Fuse blown, IF amp, or video processor.
8-46F5:
A high magnetron current indicates a/an:
Defective external magnetic field.
Defective AFC crystal.
Increase in duty cycle.
High standing wave ratio (SWR).
8-46F6:
Low or no mixer current could be caused by:
All of the above.
Local oscillator frequency misadjustment.
TR cell failure.
Mixer diode degradation.
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