Chapter 1: VHF-HF Communications

Question 1

what does VHF communication provide?

Answer 1

short range air to air or air to ground voice comms

Question 2

primary use of VHF & HF

Answer 2

air traffic control

Question 3

communication band for VHF

Answer 3

118 - 136 MHz

Question 4

factors affecting range of VHF communications are?

Answer 4

1) transmission power of aircraft and ground station
2) height of transmitter & receiver
3) obstacles that would block the signals

Question 5

what does a VHF system consist of?

Answer 5

1) frequency control panel
2) transceiver
3) antenna

Question 6

what does the frequency control panel do?

Answer 6

frequency selection

voice transmission

Question 7

what is a transceiver

Answer 7

transmitter + receiver

Question 8

what does an antenna do?

Answer 8

receive and transmit radio signals via RF-Coax Line

Question 9

what kind of wave is HF communication?

Answer 9

sky wave

Question 10

what does HF communication provide?

Answer 10

long range air to air or air to ground voice comms

Question 11

communication band for HF

Answer 11

2 - 22 MHz

Question 12

factors affecting range of HF communications

Answer 12

1) transmission power of aircraft & ground station
2) time of the day
3) season of the year
4) disturbance in ionosphere
5) location
6) frequency of use

Question 13

what does a HF system consist of?

Answer 13

1) frequency and power control panel
2) transceiver
3) coupler

Question 14

what is a coupler?

Answer 14

matching network for antenna, to save power

Question 15

what does a SELCAL system consist of?

Answer 15

1) decoder
2) tone selector
3) selcal lamp/switches

Question 16

what does the ELT consist of?

Answer 16

1) battery
2) antenna
3) lanyard cord
4) plastic water bag

Question 17

what signals does the ELT transmit?

Answer 17

1) civil rescue: 121.5 MHz
2) military rescue: 243.0 MHz

Question 18

emission duration for ELT

Answer 18

48 hours