Radio Flashcards
What is a VHF Radio?
A VHF (Very High Frequency) radio refers to a band of radio frequencies between 30-300 MHz.
What is a key limitation of a VHF Radio?
The main limitation is that it can only travel in straight lines from the transmitter, leading to shielding of the reception by the curvature of the Earth and obstacles such as mountains
What are the primary controls present on the dashboard of a typical light airctaft?
- Transmit Selector
- Speaker/PhonesSelector
- Frequency Display Window (MHz)
- On/Off Volume Control
- Squelch Control
- Navigation Section
What is the transmit selector and what is its purpose?
The transmit selector is a binary switch that is used to select the transmitting radio.
What is the speaker/phones selector and what is its purpose?
The speaker/phones selector is a switch that is used to select the medium of communication (headset or hand-held microphone).
What is the frequency display window and what is its purpose?
The frequency display window displays the selected frequency in MHz.
How to change the radio frequency?
The frequency is changed using two large knobs immiediately below the frequency display window. The left knob selects the whole numbers, whilst the right knob selects the decimal numbers.
What is the on/off volume control and what is its purpose?
The on/off volume control is a control used to turn the radio off/on and control the volume of the signal in the receiving device.
What is the squelch control and what is its purpose?
The squelch control is used to control the sensitivity of the reception of naturally occuring background noises (referred to as squelch)
How to set squelch control?
- Set desired volume
- Rotate squelch control until background noise can be heard
- Rotate in opposite direction until the noise dissappears
How to use the headset?
- Turn on VHF radio and select desired frequency
- Set transmit selector to VHF position
- Place speakers/phone selector to phone position
- Set desired volume of headset
- Adjust the squelch
- To transmit, press the ‘press to talk’ button located on the control column
How to use hand-held microphone?
- Turn on VHF radio and select desired frequency
- Set transmit selector to VHF position
- Place speakers/phone selector to speaker position
- Set desired volume of headset
- Adjust the squelch
- To transmit, press the ‘press to talk’ button located on the side or front of microphone
Recite Phonic Alphabet
Alpha
Bravo
Charlie
Delta
Echo
Foxtrot
Golf
Hotel
India
Juliett
Kilo
Lima
Mike
November
Oscar
Papa
Quebec
Romeo
Sierra
Tango
Uniform
Victor
Whiskey
X-Ray
Yankee
Zulu
How are numbers transmitted?
Numbers are transmitted digit by digit (3 - three or tree, 9 - niner). Whole hundreds and thousands can be pronounced with the words “hundred” or “thousand” etc.
How is time transmitted?
Time is expressed as a four figure (hours and minutes) or only minutes past current hour.
“Zero Three Three Five” or “Three Five”
How to indicate an emergency message?
To indicate a message is vital, prefix it with the word “MAYDAY” three times
How to indicate urgency message or PAN-PAN Call
To indicate a message is vital but not a situation placing the aircraft in vital danger, prefix it with the word “PAN-PAN” three times
What are the key contents of a distress message?
Who you are
What you are
Where you are
What has happened
What you intend to do
How to troubleshoot radio?
- Check radio is turned on and volume is correctly set
- Check squelch control is correctly set
- Check that the correct frequency is selected
- Check avionics to be on (if applicable)
- Check transmit selector switch is set to VHF radio
- Check that the speaker/phones selector is correctly set
- Check headset volume is correctly set (if applicable)
- If using headphones, check the two plugs are correctly plugged
- If using hand-held microphone, check that it is correctly plugged
- Check the radio circuit breakers and fuses
What is radio voice communication in aviation referred to as?
It is referred to as ‘Radio Telephony’ (RTF or R/F)
What is the avergae hearing range of a human?
20-20000 Hz
What does a Hz refer to
One cycle of a wave per second
What is the shape of a sound wave?
Sine wave/curve
What does the frequency refer to?
The amount of waves occuring within one second
What does amplitude refer to?
Amplitude refers to the height between the creset or trough and the resting point
What is the speed of sound?
approximately 340m/s
How to transmit cloud cover?
- In eights of the sky covered (eights is communicated as “oktas”
e.g half of sky covered = four oketas
What is an Automatic Direction Finder (ADF)?
An ADF is a navigation electronically connected to an instrument in the cockpit. It receives signals from a non-directional beam, transmitted from the ground. The needle on the instrument points in the direction of the station.
What is radar?
Radar (radio detection and ranging) is used to establish the bearing, distance and altitude of nearby other aircraft through the transmission and reception of an electromagnetic signal.
Echo: Skin Paint
System Primary Radar
What is primary radar?
Primary Radar is a device that transmits a pulse and relies on the reflection of it to a reciever to convert the details of the reflection into bearing and distance
Important transponder codes:
1200 - VFR aircraft not participating in radar information services
7600 - radio failure
7700 - serious emergency
What are the transponder operating modes?
OFF - Power is off
SBY - Standby, power on, ready to operate
ON - Transmits the set code when interrogated
ALT - Transmits the set code and aircraft altitude when interrogated
TST - Checks function, transmits code once
IDENT - Symbol flashes on ATC radar screen
What are the three degrees of emergency?
Mayday
Pan-Pan
Security
What does a Steady Green Signal during flight mean?
Authorised to land if yoiu are satisfied that no collision risk exists
What does a Steady Green Signal on ground mean?
Authorised to take-off if you are satisfied no collision risk exists
What does a Steady Red Signal during flight mean?
Give way to other aircraft and continue circling
What does a Steady Red Signal on ground mean?
Stop where you are
What does a Flashing Green Signal during flight mean?
Return for immiediate landing
What does a Flashing Green Signal on ground mean?
Authorised to taxi if you are satisfied that no risk of collision exists
What does a Flashing Red Signal during flight mean?
Aerodome unsafe - do not land
What does a Flashing Red Signal on ground mean?
Taxi clear of landing area in use
What does a Flashing White Signal during flight mean?
Nothing
What does a Flashing White Signal on ground mean?
Return to starting point of aerodrome
What is the emergency locator transmitter?
The emergency locator transmitter (ELT) is a VHF radio transmitter capable of sending a signal simulatenously on the international distress frequencies (121.5 and 243 MHz)
What does CTAF refer to?
CTAF (Common Traffic Advisory Frequency) refers to the given VHF radio frequency of a specific non-towered airport within AU, U.S and Canada.
What is deemd as an unauthorised transmission?
A transmission that involves swearing or talking in a foreign language
When should an inbound call be made?
10nm out from an airport (dependent on size and speed of aircraft)
What type of calls are mandatory?
Calls to indicate a potential collision
What does QNH mean?
Sea level pressure
What to do if there is no published CTAF frequency?
If there is no published CTAF frequency the standard frequency to use in
Australia also known as the Multicom frequency is 126.7.
Where can one find the area frequencies for flight outside of controlled airspace?
On the VTC, VNC, ERC Low or in the ERSA
