Annex B03 Transmission Line and Antenna Fundamentals

Question 0

Impedence

Answer 0

Total resistive force that an AC electrical signal must overcome while it moves through the line. Ratio of voltage to current on any given point of the transmission line

Question 1

Purpose of a Transmission Line

Answer 1

To transfer energy output of the transmitter to an antenna or ancillary device with the least possible power loss

Question 2

Standing Wave

Answer 2

The sum of two (2) waves of the same frequency traveling on a line in opposite directions which can be detrimental to successfully sending a signal to the antenna

Question 3

Resonant Line vs Non-resonant Line

Answer 3

Resonant- a line that has standing waves of current and voltage

Non-resonant- a line that has NO standing waves of current and voltage

Question 4

Standing Wave Ratio

Answer 4

Ratio of max/min voltages on a transmission line
Always expressed in whole numbers
Measures a transmission line and an antenna

Question 5

Standing Wave Ratio required for optimum performance of a transmitter

Answer 5

1:1 SWR will provide best performance between transmitter, transmission line and an antenna

Question 6

Three (3) parts of an antenna

Answer 6

Coupler, Feeder (transmission line), Antenna

Question 7

Purpose of a Coupler

Answer 7

Instrument that electronically matches the impedance of the transmission line to the antenna IOT maximize power transfer

Question 8

Three (3) factors that determine the type, size, and shape of an antenna

Answer 8

Frequency of operation of the transmitter
Amount of power to be radiated
General direction of the receiving set

Question 9

Two (2) most common types of antenna polarization used in military systems

Answer 9

Vertical and Horizontal

Question 10

Directivity

Answer 10

Measure of how that antenna radiates more electromagnetic energy in a certain direction vice others

Question 11

Gain

Answer 11

Ratio between the amount of energy propagated in a particular direction compared to the energy that would be propagated if the antenna was omnidirectional

Question 12

Reciprocity

Answer 12

Property of interchangeability of the same antenna for transmitting and receiving

Question 13

Two (2) primary components of an electromagnetic wave

Answer 13

Electric Field

Magnetic Field

Question 14

Electromagnetic Spectrum

Answer 14

Range of electromagnetic waves arranged in order of their frequencies

Question 15

Field that is produced when electric field and magnetic field are combined on an antenna

Answer 15

Induction Field

Question 16

Field responsible for electromagnetic radiation from the antenna

Answer 16

Radiation field