MIDTERM TEST Flashcards
The impedance of an aircraft headphone set is:
500-600ohms
The standard audio test frequency is?
1kHz
The audio bandwidth for aircraft systems is?
350Hz to 2.5kHz
What is the impedance of an aircraft system microphone?
150ohms
Where does the required microphone bias voltage come from?
The radio in use
What output voltage would you expect to have from an aircraft microphone?
1Vrms
The ring of the shown Jack is for?
Microphone Audio
If an amplifier has a gain of 60dB and input voltage is 1mV what is the output voltage?
1V
A transmitter has 3 stages with gains of 6dB, 12dB, and 8dB (total 26dB) if 60mW is input power what is the output power?
24W
If a signal generator attenuator is set to minus 30dBm what output power is sent?
1microWatt
When testing a 121.5MHz ELT what time restriction must be observed?
First 5min after the hour
ELTs have an arrow on the case. For proper installation where should the arrow point?
Towards the direction of flight / front of aircraft
What advantage does the 406MHz ELT have over 121.5MHz ELT?
Gives more accurate position coordinates
ELT batteries must be replaced after activation of the ELT for a period of?
Unknown duration
Replacement of ELT batteries should be done?
When testing shows insufficient charge
When carrying out a VSWR test a forward power of 100W and reverse power of 1 watt is measured, what is the VSWR?
1.2:1
What value of VSWR is the acceptable limit(100W to 10W)?
2:1
If the antenna transmission line (co-ax) is open circuit what VSWR or SWR would be measured?
5:1
When testing a transmission line with a TDR, what indication would a short in the line show as?
Downward deflection on trace
The communication receiver squelch circuit uses _____ to operate the switch/gate?
Internal receiver noise
An ELT has to be inspected every?
1 year
What is the transmits power output used on the 406MHz ELT?
5Watts
Ground stations are identified during radios communications by?
Airport name and station type, ie Toronto tower.
What is the spoken word for distress?
Mayday
The 406 MHz ELT output consists of a ______ but pulse train
112
What does the term selectivity of a radio receiver refer to?
It’s ability to choose only the desired frequency
What is the image frequency of a radio receiver if the local oscillator is 111.2MHz and the radio is tuned to receive 121.9MHz
100.5MHz
The 406 ELT transmits for ______ every _______
0.5s every 50s
The 406MHz ELT output is a digital format that uses ______ modulation
Phase/DPSK
According to the radiotelephone operators guide Coordinated Universal time (UTC) is used to avoid confusion between different time zones. What is the accepted abbreviation for UTC?
Zulu time
