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General Licensing Class. Coax Cable. Lake Area Radio Klub Spring 2012. Amateur Radio General Class Element 3 Course Presentation. ELEMENT 3 SUB-ELEMENTS (Groupings) 1 - Your Passing CSCE 2 - Your New General Bands 3 - FCC Rules 4 - Be a VE 5 - Voice Operations 6 - CW Lives

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General licensing class

General Licensing Class

Coax Cable

Lake Area Radio Klub

Spring 2012


Amateur radio general class element 3 course presentation

Amateur Radio General ClassElement 3 Course Presentation

  • ELEMENT 3 SUB-ELEMENTS(Groupings)

    • 1 - Your Passing CSCE

    • 2 - Your New General Bands

    • 3 - FCC Rules

    • 4 - Be a VE

    • 5 - Voice Operations

    • 6 - CW Lives

    • 7 - Digital Operating

    • 8 - In An Emergency

    • 9 - Skywave Excitement


Amateur radio general class element 3 course presentation1

Amateur Radio General ClassElement 3 Course Presentation

  • ELEMENT 3 SUB-ELEMENTS(Groupings)

    • 10 - Your HF Transmitter

    • 11 - Your Receiver

    • 12 - Oscillators & Components

    • 13 - Electrical Principles

    • 14 - Circuits

    • 15 - Good Grounds

    • 16 - HF Antennas

    • 17 - Coax Cable

    • 18 -RF & Electrical Safety


Coax cable

Coax Cable

  • 50 and 75 ohms are the typical characteristic impedances of coaxial cables used for antenna feed lines at amateur stations. (G9A02)

  • The attenuation of coaxial cable increases as the frequency of the signal it is carrying increases.(G9A05)

  • RF feed line losses usually expressed in dB per 100 ft. (G9A06)


Coax cable1

Coax Cable


Coax cable2

Coax Cable

  • The percentage of power loss that would result from a transmission line loss of 1 dB would be approx. 20.5 %. (G5B10)

  • 300 ohms is the characteristic impedance of flat ribbon TV type twinlead. (G9A03)

  • The distance between the centers of the conductors and the radius of the conductors determine the characteristic impedance of a parallel conductor antenna feed line. (G9A01)

300 Ohm Twin Lead

Air Dielectric Coaxial Cable

Parallel two-wire line


Coax cable3

Coax Cable

  • To prevent standing waves on an antenna feed line, the antenna feed-point impedance must be matched to the characteristic impedance of the feed line. (G9A07)

  • A difference between feed-line impedance and antenna feed-point impedance is the reason for the occurrence of reflected power at the point where a feed line connects to an antenna. (G9A04)

  • Standing wave ratio can also be determined with a directional wattmeter. (G4B10)


Coax cable4

Coax Cable

  • A standing wave ratio of 1:1 will result from the connection of a 50-ohm feed line to a non-reactive load having a 50-ohm impedance. (G9A11)

SWR = Z1 / Z2

50 / 50

1 : 1 VSWR


Coax cable5

Coax Cable

  • If you feed a vertical antenna that has a 25-ohm feed-point impedance with 50-ohm coaxial cable, the SWR will be 2:1. (G9A12)

  • A 4:1 standing wave ratio will result from the connection of a 50-ohm feed line to a non-reactive load having a 200-ohm impedance. (G9A09)

  • A standing wave ratio of 5:1 will result from the connection of a 50-ohm feed line to a non-reactive load having a 10-ohm impedance. (G9A10)

SWR = Z1 / Z2

50 / 25

2:1 VSWR

SWR = Z1 / Z2

200/ 50

4:1 VSWR

50/ 10

5:1 VSWR

SWR = Z1 / Z2


Coax cable6

Coax Cable

  • If the SWR on an antenna feed line is 5 to 1, and a matching network at the transmitter end of the feed line is adjusted to 1 to 1 SWR, the resulting SWR on the feed line is still 5 to 1. (G9A08)

    • The antenna tuner allows the transmitter to see a matched impedance

    • This delivers full power.

    • It does not change the antenna or feedline impedance on its output.

  • If you feed an antenna that has a 300-ohm feed-point impedance with 50-ohm coaxial cable, the SWR will be 6:1. (G9A13)

  • Antenna tuner with built in dual needle SWR meter

    SWR = Z1 / Z2

    300/ 50

    6:1 VSWR


    Coax cable7

    Coax Cable

    • The type-N connector is a moisture-resistant RF connector useful to 10 GHz. (G6C16)

    Type-N

    Type-N


    Coax cable8

    Coax Cable

    • The SMA connector is a small threaded connector suitable for signals up to several GHz. (G6C18)

    • A PL-259 connector is commonly used for RF service at frequencies up to 150 MHz. (G6C13)

    A high quality SMA connector is useable to 18 GHz and beyond

    Male PL-259

    PL-259 T-Connector


    Coax cable9

    Coax Cable

    • 200 feet is the maximum height above ground to which an antenna structure may be erected without requiring notification to the FAA and registration with the FCC, provided it is not at or near a public use airport. (G1B01)

    Maximum Antenna Height without FCC Approval.

    200 Ft.


    Element 3 general class question pool

    Element 3 General Class Question Pool

    Coax Cable

    Valid July 1, 2011

    Through

    June 30, 2015


    General licensing class

    G9A02 What are the typical characteristic impedances of coaxial cables used for antenna feed lines at amateur stations?

    25 and 30 ohms

    50 and 75 ohms

    80 and 100 ohms

    500 and 750 ohms


    General licensing class

    G9A05 How does the attenuation of coaxial cable change as the frequency of the signal it is carrying increases?

    It is independent of frequency

    It increases

    It decreases

    It reaches a maximum at approximately 18 MHz


    G9a06 in what values are rf feed line losses usually expressed

    G9A06 In what values are RF feed line losses usually expressed?

    Ohms per 1000 ft

    dB per 1000 ft

    Ohms per 100 ft

    dB per 100 ft


    G5b10 what percentage of power loss would result from a transmission line loss of 1 db

    G5B10 What percentage of power loss would result from a transmission line loss of 1 dB?

    10.9 %

    12.2 %

    20.5 %

    25.9 %


    G9a03 what is the characteristic impedance of flat ribbon tv type twinlead

    G9A03 What is the characteristic impedance of flat ribbon TV type twinlead?

    50 ohms

    75 ohms

    100 ohms

    300 ohms


    General licensing class

    G9A01 Which of the following factors determine the characteristic impedance of a parallel conductor antenna feed line?

    The distance between the centers of the conductors and the radius of the conductors

    The distance between the centers of the conductors and the length of the line

    The radius of the conductors and the frequency of the signal

    The frequency of the signal and the length of the line


    G9a07 what must be done to prevent standing waves on an antenna feed line

    G9A07 What must be done to prevent standing waves on an antenna feed line?

    The antenna feed point must be at DC ground potential

    The feedline must be cut to an odd number of electrical quarter wavelengths long

    The feedline must be cut to an even number of physical half wavelengths long

    The antenna feed point impedance must be matched to the characteristic impedance of the feed line


    General licensing class

    G9A04 What is the reason for the occurrence of reflected power at the point where a feedline connects to an antenna?

    Operating an antenna at its resonant frequency

    Using more transmitter power than the antenna can handle

    A difference between feed line impedance and antenna feed point impedance

    Feeding the antenna with unbalanced feedline


    G4b10 which of the following can be measured with a directional wattmeter

    G4B10 Which of the following can be measured with a directional wattmeter?

    Standing Wave Ratio

    Antenna front-to-back ratio

    RF interference

    Radio wave propagation


    General licensing class

    G9A11 What standing-wave-ratio will result from the connection of a 50-ohm feed line to a non-reactive load having a 50-ohm impedance?

    2:1

    1:1

    50:50

    0:0


    General licensing class

    G9A12 What would be the SWR if you feed a vertical antenna that has a 25-ohm feed-point impedance with 50-ohm coaxial cable?

    2:1

    2.5:1

    1.25:1

    You cannot determine SWR from impedance values


    General licensing class

    G9A09 What standing-wave-ratio will result from the connection of a 50-ohm feed line to a non-reactive load having a 200-ohm impedance?

    4:1

    1:4

    2:1

    1:2


    General licensing class

    G9A10 What standing-wave-ratio will result from the connection of a 50-ohm feed line to a non-reactive load having a 10-ohm impedance?

    2:1

    50:1

    1:5

    5:1


    General licensing class

    G9A08 If the SWR on an antenna feedline is 5 to 1, and a matching network at the transmitter end of the feedline is adjusted to 1 to 1 SWR, what is the resulting SWR on the feedline?

    1 to 1

    5 to 1

    Between 1 to 1 and 5 to 1 depending on the characteristic impedance of the line

    Between 1 to 1 and 5 to 1 depending on the reflected power at the transmitter


    General licensing class

    G9A13 What would be the SWR if you feed a folded dipole antenna that has a 300-ohm feed-point impedance with 50-ohm coaxial cable?

    1.5:1

    3:1

    6:1

    You cannot determine SWR from impedance values


    G6c16 which of the following describes a type n connector

    G6C16Which of the following describes a Type-N connector?

    A moisture-resistant RF connector useful to 10 GHz

    A small bayonet connector used for data circuits

    A threaded connector used for hydraulic systems

    An audio connector used in surround-sound installations


    G6c18 what is a type of sma connector

    G6C18What is a type of SMA connector?

    A large bayonet-type connector usable at power levels in excess of 1 KW.

    A small threaded connector suitable for signals up to several GHz.

    A connector designed for serial multiple access signals.

    A type of push-on connector intended for high-voltage applications.


    G6c13 which of these connector types is commonly used for rf service at frequencies up to 150 mhz

    G6C13 Which of these connector types is commonly used for RF service at frequencies up to 150 MHz?

    Octal

    RJ-11

    PL-259

    DB-25


    General licensing class

    G1B01 What is the maximum height above ground to which an antenna structure may be erected without requiring notification to the FAA and registration with the FCC, provided it is not at or near a public-use airport?

    50 feet

    100 feet

    200 feet

    300 feet

    33


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