Antenna Flashcards
Aircraft radios use ___ channels which are spaced __ _Hz apart, with power ratings between _ and __ Watts
760, 25, 2, 25
Antennas radiate EM waves, which convert __ energy into __ energy
AC EM
The ___ acts a dielectric between the Earth and the antenna
air
At high frequencies, the antenna will be too ___ and will be inductive and resistive.
long
At low frequencies, the antenna will be too ___ and will show capacitance
short
Reactance and resistance are collectively known as ___
impedance
A dipole is an antenna which is ___, with each section __ of a wavelength long.
split at the centre, 0.25
Radio waves passing by the antenna will induce voltage and current along the wires, ___ in amplitude but ___ in phase to each other.
equal, opposite
A coil ___ the inductance of an antenna and ___ its natural frequency, while a capacitor in series ___ the capacitance and ___ the natural frequency.
increases, reduces, reduces, raises
A unipole is a ___ length conductor, mounted ___ on the fuselage.
0.25, vertically.
For frequencies between _ and __ _Hz, the aircraft fuselage can be used as the radiating/receiving element.
2 30 MHz
At Very High Frequencies, ____ _Hz and above, a waveguide must be used.
3,000 MHz
There are two types of basic antenna, ___ and ___
Hertz, Marconi
Hertz are ___-wave, dipole antennas
half
Hertz antenna are positioned ____
well above the ground
