RF Theory

Question 1

high range of frequency signal which has a specific amplitude, frequency, and phase levels, but it does not hold any data.

Answer 1

Carrier Wave

Question 2

This signal is what holds the message or traffic. Signals are sent through what is called a modulator to attach the data onto a signal and is then sent out across the airwaves to a destination.

Answer 2

Modulating Signal

Question 3

is process by which voice, music, and other “intelligence” is added to the radio waves produced by a transmitter.

Answer 3

Modulation

Question 4

the fluctuations in power (amplitude) of the wave carries the data.

Answer 4

Amplitude modulation (AM)

Question 5

If this input signal is added to the pure carrier wave, it will thereby change the frequency of the carrier wave. In that way, users can use changes of frequency to carry speech information.

Answer 5

Frequency Modulation (FM)

Question 6

535 kHz - 1605 kHz

Answer 6

AM radio frequency

Question 7

87.9 MHz - 107.9MHz

Answer 7

FM radio frequency

Question 8

the decrease in a property, as energy, per unit of a wave of a beam of particles, which increases as a result of absorption, scattering, spreading in three dimensions, etc.

Answer 8

Attenuation

Question 9

is the loss of signal strength in networking cables or connections.

Answer 9

Attenuation (laymens)

Question 10

A method to help with ______ (besides shortening the distance) is through the use of repeaters or amplifiers.

Answer 10

Attenuation

Question 11

the amplification of a signal which can compensate for losses

Answer 11

Gain

Question 12

uses an RF amplifier to increase the signal strength

Answer 12

Active Gain

Question 13

uses no extra amplification and relies fully on the directionality of the antenna for increased RF energy in a desired direction.

Answer 13

Passive gain

Question 14

based on a “Bel”, a unit of strength named after early telecommunications pioneer, Alexander Graham Bell.
__ is a measure of relative power and cannot be converted into watts

Answer 14

dB

Question 15

decibel relative to milliwatt.

the amount of power that an antenna or amplifier is able to produce, or how much signal is present at a site.

= dB+30, so 0dB is 30dBm

Answer 15

dBm

Question 16

you add 3 dBm you will double your value

1 Watt = 30dBm
2W = 33dBm

and vice versa

1W = 30 dBm
0.5W = 27 dBm

Answer 16

Rule of 3

Question 17

to add 10 times the power, you add 10dBm
1W = 30 dBm

10W = 40 dBm

Answer 17

rule of 10

Question 18

Signal loss due to a long distance of travel or running into objects is called what?

Answer 18

Attenuation

Question 19

ensures that as much RF energy captured by the antenna is passed through the transmission line and onto the modem

Answer 19

Matching

Question 20

when two adjacent devices on a circuit have different impedances

Answer 20

Impedance mismatch

Question 21

describes the ratio of mismatch. If the VSWR is high enough, the standing wave can cause signal distortion and damage the transmitter.

Answer 21

VSWR

Question 22

These systems allow communication in only one direction.

Answer 22

Simplex

Question 23

each participant can transmit and receive, but only one station can transmit at a time.

Answer 23

Half-Duplex

Question 24

Enables each transmitters to send and receive at the same time.

Answer 24

Full-Duplex

Question 25

an attacker must establish a physical connection either locally or remotely.

Answer 25

For 802.3 (Ethernet based) networks

Question 26

If a target is using a directional antenna aimed away from a collection team, it will be much harder to pick up its signal.

Answer 26

802.3