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Flashcards in Antenna Deck (20)
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1
Q

Aircraft radios use ___ channels which are spaced __ _Hz apart, with power ratings between _ and __ Watts

A

760, 25, 2, 25

2
Q

Antennas radiate EM waves, which convert __ energy into __ energy

A

AC EM

3
Q

The ___ acts a dielectric between the Earth and the antenna

A

air

4
Q

At high frequencies, the antenna will be too ___ and will be inductive and resistive.

A

long

5
Q

At low frequencies, the antenna will be too ___ and will show capacitance

A

short

6
Q

Reactance and resistance are collectively known as ___

A

impedance

7
Q

A dipole is an antenna which is ___, with each section __ of a wavelength long.

A

split at the centre, 0.25

8
Q

Radio waves passing by the antenna will induce voltage and current along the wires, ___ in amplitude but ___ in phase to each other.

A

equal, opposite

9
Q

A coil ___ the inductance of an antenna and ___ its natural frequency, while a capacitor in series ___ the capacitance and ___ the natural frequency.

A

increases, reduces, reduces, raises

10
Q

A unipole is a ___ length conductor, mounted ___ on the fuselage.

A

0.25, vertically.

11
Q

For frequencies between _ and __ _Hz, the aircraft fuselage can be used as the radiating/receiving element.

A

2 30 MHz

12
Q

At Very High Frequencies, ____ _Hz and above, a waveguide must be used.

A

3,000 MHz

13
Q

There are two types of basic antenna, ___ and ___

A

Hertz, Marconi

14
Q

Hertz are ___-wave, dipole antennas

A

half

15
Q

Hertz antenna are positioned ____

A

well above the ground

16
Q

Hertz antenna radiate ____

A

horizontally or vertically

17
Q

Hertz antenna are used for frequencies of ____

A

2 MHz and above

18
Q

Marconi are ___-wave antennas

A

Quarter

19
Q

Marconi antenna are positioned ___ to the Earth

A

perpendicular

20
Q

Marconi antenna are used for frequencies of ___

A

2 MHz and below