3-K-073: Equipment Functions
3-73K1:
Some aircraft and avionics equipment operates with a prime power line frequency of 400 Hz. What is the principle advantage of a higher line frequency?
The magnetic devices in a 400 Hz power supply such as transformers, chokes and filters are smaller and lighter than those used in 60 Hz power supplies.
400 Hz power supplies draw less current than 60 Hz supplies allowing more current available for other systems on the aircraft.
A 400 Hz power supply generates less heat and operates much more efficiently than a 60 Hz power supply.
400 Hz power supplies are much less expensive to produce than power supplies with lower line frequencies.
3-73K2:
Aviation services use predominantly ____ microphones.
Dynamic
Carbon
Condenser
Piezoelectric crystal
3-73K3:
Typical airborne HF transmitters usually provide a nominal RF power output to the antenna of ____ watts, compared with ____ watts RF output from a typical VHF transmitter.
100, 20
10, 50
50, 10
20, 100
3-73K4:
Before ground testing an aircraft RADAR, the operator should:
Ensure that the area in front of the antenna is clear of other maintenance personnel to avoid radiation hazards.
Be sure the receiver has been properly shielded and grounded.
First test the transmitter connected to a matched load.
Measure power supply voltages to prevent circuit damage.
3-73K5:
What type of antenna is used in an aircraft’s Very High Frequency Omnidirectional Range (VOR) and Localizer (LOC) installations?
Horizontally polarized omnidirection reception antenna.
Vertically polarized antenna that radiates an omnidirectional antenna pattern.
Balanced loop transmission antenna.
Folded dipole reception antenna.
3-73K6:
What is the function of a commercial aircraft’s SELCAL installation? SELCAL is a type of aircraft communications __________.
System where a ground-based transmitter can call a selected aircraft or group of aircraft without the flight crew monitoring the ground-station frequency.
Device that allows an aircraft’s receiver to be continuously calibrated for signal selectivity.
Transmission that uses sequential logic algorithm encryption to prevent public “eavesdropping” of crucial aircraft flight data.
System where an airborne transmitter can selectively calculate the line-of-sight distance to several ground-station receivers.
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