Personal Wireless technology Flashcards
What are frequencies from 30 to 300 megahertz (MHz) internationally designated as?
Very high.
The ultra high frequency designation applies to frequencies from
300 to 3,000 MHz.
Which of the following frequencies has the shortest wavelength?
140 MHz.
A mode of operation in which communication is possible between two or more stations, in both
directions, using the same frequency, is called
simplex.
What communication mode(s) of operation allows two or more stations to send intelligence in
both directions but not simultaneously?
Simplex and half duplex.
Producing radio frequency (RF) energy and radiating useful signals into space is the purpose of
the
transmitter.
What type modulation produces a constant amplitude transmission?
Frequency.
The ability to maintain a constant output carrier frequency refers to a transmitter’s frequency
accuracy.
The process of mixing or combining two frequencies in a nonlinear device in an amplitude
modulated (AM) receiver is called
heterodyning.
What component of a frequency modulated (FM) receiver removes the original signal from the
sidebands and recreates the audio intelligence?
Discriminator.
What characteristic enables a receiver to reproduce a desired signal from several closely spaced
stations or from interfering frequencies?
Selectivity.
The total resistive properties of a circuit when resistance, capacitive reactance, and inductive
reactance are formulated together is called
impedance.
What transmission line is very common in both fixed and tactical application?
Flexible coax.
What field provides the basis of radio frequency (RF) communications by detaching from the
conductor and traveling through space?
Radiation.
For best communications, the transmitting antenna
and receiving antenna should have the same polarization.
What standard antenna is used for antenna gain comparison?
Isotropic.
When the gain of an anisotropic radiator is compared to the isotropic radiator, the stronger
signal of the directional antenna is expressed as
decibels (dB) gain.
What is the shortest wavelength an antenna can be made resonant?
Half.
What tuning devices are adjusted when tuning the resonant transmission line-resonant antenna
connection?
Inductors and capacitors.
What limits a direct wave to normally less than 20 miles?
Curvature of the earth.
Which type of precipitation attenuates radio frequency (RF) energy just like rain?
Fog.
What ratio is used to measure the desired signal strength relative to the background noise?
Signal-to-noise.
What combination of Air Force instructions (AFI) do you use for guidance when determining a
technical solution for personal wireless communications systems (PWCS)?
AFI 33–106 and AFI 33–201V1.
Which personal wireless communications system (PWCS) device can be used for command and
control?
Land mobile radio (LMR).
