Aircraft Antenna Systems and Frequencies

Question 1

What type of antenna pattern is radiated from a ground station phased-array directional antenna when transmitting the PPM pulses in a Mode S interrogation signal of an aircraft’s Traffic alert and Collision Avoidance System (TCAS)
installation?

Answer 1

1030 MHz directional pattern.

Question 2

What type of antenna is used in an aircraft’s Instrument Landing System (ILS) marker beacon installation?

Answer 2

A balanced loop reception antenna.

Question 3

What is the frequency range of an aircraft’s Very High Frequency (VHF) communications?

Answer 3

118.000 MHz to 136.975 MHz (worldwide up to 151.975 MHz)

Question 4

Aircraft Emergency Locator Transmitters (ELT) operate on what frequencies?

Answer 4

121.5, 243 and 406 MHz.

Question 5

What is the frequency range of an aircraft’s radio altimeter?

Answer 5

4250 MHz to 4350 MHz

Question 6

What type of antenna is attached to an aircraft’s Mode C transponder installation and used to receive 1030 MHz terrogation signals from the Air Traffic Control Radar Beacon System (ATCRBS)?

Answer 6

An L-band monopole blade-type omnidirectional antenna.