Complete

1. Aerial is used for ……

2. The word antenna was first used by …..

3. The parameters affecting the antenna performance are ….

4. Bandwidth is …..

5. Form of the aerial depends on …

Aircraft Antennas

Directional Antenna

A. The directional antenna is a four element vertically polarized monopole array capable of transmitting in four selectable directions. The directional antenna is connected to the TCAS computer with four coaxial cables that have TNC plugs on the antenna end.

B. The TCAS uses two directional antennas. One is installed on top and the other is installed on the bottom of the airplane. These antennas transmit to and receive signals from intruder airplanes.

C. Each of the four elements of the directional antenna has a resistor that goes from the antenna element to ground. Each of the four resistors has a different value. The TCAS computer regularly does a continuity test on the antenna ports and will see the correct resistance value if the port is not shorted and not open.

* intruder airplane – самолёт нарушитель

Loop Antenna

A. The fixed loop antenna is a sealed, nonrotating, direction-sensitive r-f pick-up device for the automatic direction finder system receiver. The antenna consists of two pairs of ferrite core coils, one pair oriented parallel to and the second pair oriented perpendicular to the fore and aft axis of the airplane. Both coil pairs are coupled to the system receiver through the quadrantal error corrector and loop antenna

transmission cable.

B. The fixed loop antennas are flush-mounted from outside in individual antenna cavities on the bottom center of the fuselage at stations. The antennas have no moving parts.

Sense Antenna

A. Two ADF sense antennas are installed, one on the left wing-to-body fairing and the second on the right wing-to-body fairing. The antennas are located aft of the aft wheel well bulkhead at station 727B. A metal coating on the fairings is used as the antenna element.

B. The sense antennas provide a nondirectional reception pattern and high signal strength to the receivers.

The antennas are linearly polarized horns. Two identical antennas are used in each system of the dual LRRA system, one for transmitting and one for receiving. The antennas are connected to the receiver-transmitter through specific length coaxial cables and are flush mounted on the lower fuselage centerline

Answer

1.What antennas are used on the aircraft? 2.What system uses directional antenna? 3.Where are directional antennas located? 4. What is directional antenna designed for? 5. Why does TCAS computer regularly do a continuity test on the antenna ports? 6. What system uses the loop antenna? 7. What are the components of the loop antenna? 8. Where is the loop antenna located? 9. Does it have movable parts? 10. What does the sense antenna provide for the aircraft? 11. Where is the sense antenna installed?