Technician Licensing Class Antennas Valid July 1 2018

Technician Licensing Class Antennas Valid July 1, 2018 Through June 30, 2022 1

Amateur Radio Technician Class Element 2 Course Presentation Ø ELEMENT 2 SUB-ELEMENTS (Groupings) • • • About Ham Radio Call Signs Control Mind the Rules Tech Frequencies Your First Radio Going On The Air! Repeaters Emergency! Weak Signal Propagation 2

Amateur Radio Technician Class Element 2 Course Presentation Ø ELEMENT 2 SUB-ELEMENTS (Groupings) • Talk to Outer Space! • Your Computer Goes Ham Digital! • Multi-Mode Radio Excitement • Run Some Interference Protection • Electrons – Go With the Flow! • It’s the Law, per Mr. Ohm! • Go Picture These! Ø Antennas • Feed Me With Some Good Coax! • Safety First! 3

Antennas • A simple dipole mounted so that the conductor is parallel to the Earth’s surface is a horizontally polarized antenna. T 9 A 03 • The direction of radiation is strongest from a half-wave dipole antenna in free space broadside to the antenna. T 9 A 10 4

Antennas • The approximate length of a 6 -meter, halfwave wire dipole antenna is 1123 inches. T 9 A 09 • To change a dipole antenna to make it resonant on a higher frequency, shorten it. T 9 A 05 5

Antennas • The approximate length, in inches, of a quarter-wave vertical antenna for 146 MHz is 19”. T 9 A 08 19” 6

Antennas • The quad, Yagi, and dish antennas are directional antennas. T 9 A 06 quad Yagi dish 7

Antennas • The beam antenna concentrates signals in one direction. T 9 A 01 8

Antennas • With a directional antenna you may be able to find a reflected path to a distant repeater if the direct path is obstructed. T 3 A 05 9

Antennas • A directional antenna would be useful for a hidden transmitter hunt. • To locate sources of noise interference or jamming, use radio direction finding equipment. T 8 C 02 T 8 C 01 10

Antennas The increase in signal strength in a specified direction when compared to a reference antenna is referred to as the gain of an antenna. T 9 A 11 Horizontal antenna polarization is normally used for longdistance weak-signal CW and SSB contacts using the 11 VHF and UHF bands. T 3 A 03

Antennas • Signals could be significantly weaker if the antennas at opposite ends of a VHF or UHF line of sight radio link are not using the same polarization. A properly mounted 5/8 wavelength antenna for VHF or UHF mobile service offers a lower angle of radiation and more gain than a ¼ wavelength antenna and usually provides improved coverage. T 3 A 04 T 9 A 12 12

Antennas • A type of loading when referring to an antenna is when an inductor is inserted in the radiating portion of the antenna to make it electrically longer and is called a loading coil. T 9 A 02 13

Element 2 Technician Class Question Pool Antennas Valid July 1, 2018 Through June 30, 2022 14

T 9 A 03 Which of the following describes a simple dipole mounted so the conductor is parallel to the Earth's surface? A. B. C. D. A ground wave antenna A horizontally polarized antenna A rhombic antenna A vertically polarized antenna 15

T 9 A 10 In which direction is the radiation strongest from a half-wave dipole A. B. C. D. antenna in free space? Equally in all directions Off the ends of the antenna Broadside to the antenna In the direction of the feedline 16

T 9 A 09 What is the approximate length, in inches, of a 6 meter 1/2 -wavelength wire dipole antenna? A. B. C. D. 6 50 112 236 17

T 9 A 05 How would you change a dipole antenna to make it resonant on a higher frequency? A. B. C. D. Lengthen it Insert coils in series with radiating wires Shorten it Add capacity hats to the ends of the radiating wires 18

T 9 A 02 Which of the following is true regarding vertical antennas? A. The magnetic field is perpendicular to the Earth B. The electric field is perpendicular to the Earth C. The phase is inverted D. The phase is reversed 19

T 9 A 08 What is the approximate length, in inches, of a quarter-wavelength vertical antenna for 146 MHz? A. B. C. D. 112 50 19 12 20

T 9 A 06 What type of antennas are the quad, Yagi, and dish? A. B. C. D. Non-resonant antennas Loop antennas Directional antennas Isotropic antennas 21

T 9 A 01 What is a beam antenna? A. An antenna built from aluminum Ibeams B. An omnidirectional antenna invented by Clarence Beam C. An antenna that concentrates signals in one direction D. An antenna that reverses the phase of received signals 22

T 3 A 05 When using a directional antenna, how might your station be able to access a distant repeater if buildings or obstructions are blocking the direct line of sight path? A. Change from vertical to horizontal polarization B. Try to find a path that reflects signals to the repeater C. Try the long path D. Increase the antenna SWR 23

T 8 C 01 Which of the following methods is used to locate sources of noise interference or jamming? A. B. C. D. Echolocation Doppler radar Radio direction finding Phase locking 24

T 8 C 02 Which of these items would be useful for a hidden transmitter hunt? A. Calibrated SWR meter B. A directional antenna C. A calibrated noise bridge D. All of these choices are correct 25

T 9 A 11 What is meant by the gain of an antenna? A. The additional power that is added to the transmitter power B. The additional power that is lost in the antenna when transmitting on a higher frequency C. The increase in signal strength in a specified direction when compared to a reference antenna D. The increase in impedance on receive or transmit compared to a reference antenna 26

T 3 A 03 What antenna polarization is normally used for long-distance weak-signal CW and SSB contacts using the VHF and UHF bands? A. B. C. D. Right-hand circular Left-hand circular Horizontal Vertical 27

T 3 A 04 What can happen if the antennas at opposite ends of a VHF or UHF line of sight radio link are not using the same polarization? A. The modulation sidebands might become inverted B. Signals could be significantly weaker C. Signals have an echo effect on voices D. Nothing significant will happen 28

T 9 A 12 What is an advantage of using a properly mounted 5/8 UHF mobile wavelength antenna for VHF or service? A. It offers a lower angle of radiation and more gain than a 1/4 wavelength antenna and usually provides improved coverage B. It features a very high angle of radiation and is better for communicating via a repeater C. The 5/8 wavelength antenna completely eliminates distortion caused by reflected signals D. The 5/8 wavelength antenna offers a 10 -times power gain over a 1/4 wavelength design 29

T 9 A 13 Why are VHF or UHF mobile antennas often mounted in the center of the vehicle roof? A. Roof mounts have the lowest possible SWR of any mounting configuration B. Only roof mounting can guarantee a vertically polarized signal C. A roof mounted antenna normally provides the most uniform radiation pattern D. Roof mounted antennas are always the easiest to install 30

T 9 A 02 Which of the following terms describes a type of loading when referring to an antenna? A. Inserting an inductor in the radiating portion of the antenna to make it electrically longer B. Inserting a resistor in the radiating portion of the antenna to make it resonant C. Installing a spring at the base of the antenna to absorb the effects of collisions with other objects D. Making the antenna heavier so it will resist wind effects when in motion 31