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General Licensing Class “G3”. Presented by the Acadiana Amateur Radio Assoc. Lafayette, Louisiana. General Class Element 3 Course Presentation. ELEMENT 3 SUB-ELEMENTS G1 – Commission’s Rules G2 – Operating Procedures G3 – Radio Wave Propagation G4 – Amateur Radio Practices

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General licensing class g3
General Licensing Class“G3”

Presented by the

Acadiana Amateur Radio Assoc.

Lafayette, Louisiana


General class element 3 course presentation
General Class Element 3 Course Presentation

  • ELEMENT 3 SUB-ELEMENTS

    G1 – Commission’s Rules

    G2 – Operating Procedures

    G3 – Radio Wave Propagation

    G4 – Amateur Radio Practices

    G5 – Electrical Principles

    G6 – Circuit Components

    G7 – Practical Circuits

    G8 – Signals and Emissions

    G9 – Antennas

    G0 – Electrical and RF Safety


G3 radio wave propagation g3a
G3 … Radio Wave PropagationG3A

  • Sunspots and solar radiation

    • It takes approximately 8 minutes for increased ultraviolet and X-ray radiation from solar flares to affect radio-wave propagation on the Earth.

      (Solar winds coming towards the earth from the sun)


G3 radio wave propagation g3a1
G3 … Radio Wave PropagationG3A

  • Sunspots and solar radiation(cont)

    • The typical sunspot cycle is approximately 11 years long


G3 radio wave propagation g3a2
G3 … Radio Wave Propagation G3A

  • Sunspots and solar radiation(cont)

    • The sunspot number is a measure of solar activity based on counting sunspots and sunspot groups

August 2008

September 1991


G3 radio wave propagation g3a3
G3 … Radio Wave Propagation G3A

  • Sunspots and solar radiation(cont)

    • 2008 is hopefully the end of Solar Cycle 23 and the beginning of Solar Cycle 24.


G3 radio wave propagation g3a4
G3 … Radio Wave PropagationG3A

  • Ionospheric disturbances

    • Geomagnetic disturbance is a significant change in the Earth's magnetic field over a short period.

    • A Sudden Ionospheric Disturbance (SID) disrupts signals on lower frequencies more than those on higher frequencies affecting the daytime ionospheric propagation of HF radio waves

    • An amateur station can try a higher frequency to continue communications during a sudden ionospheric disturbance.



Atmospheric layers
Atmospheric Layers

Terms we’ve heard before from space shuttle launches.

Now apply them to Ham Radio

Ionosphere

31 – 400 miles

Stratosphere

6 – 31 miles

Troposphere

0 – 6 miles


Atmospheric layers cont
Atmospheric Layers(cont)

  • Troposphere

    • Closest to Earth

    • Max ~ 16 miles

  • Ionosphere

    • 4 layers: D; E; F1; F2

    • Responsible for most long range communications

    • Ultraviolet radiation causes most ionization

    • Ionization max at midday, min at sunrise


  • How the ionosphere is formed

    Ultraviolet and other radiation from the sun

    Strikes atoms in the upper atmosphere

    Releasing an electron forming positive & negative ions

    -

    Electron

    (Negative Ion)

    +

    Positive Ion

    Electrically Neutral Atom

    How the Ionosphere is Formed

    Ultraviolet radiation is most responsible for ionization in the outer atmosphere.


    Layers of the ionosphere g3a
    Layers of the Ionosphere G3A

    • Lowest part: D layer has enough collisions to cause it to disappear after sunset

    • Remaining ions and electrons recombine, without sunlight new ones are no longer produced

    • Layer return at sunrise


    Regions in the ionosphere g3a

    At night....

    Regions in the IonosphereG3A

    During the day....

    • The “D” Region is closest to Earth

    • The “D” Region absorbs MF/HF radio signals

    • The “F2” Region is most responsible for long distance communication

    • The “D” & “E” Regions disappear

    • The “F1” & “F2” Regions combine into one with reduced ionization


    G3 radio wave propagation g3a5
    G3 … Radio Wave PropagationG3A

    • Ionospheric disturbances (cont)

      • Latitudes, greater than 45 degrees North or South latitude, have propagation paths that are more sensitive to geomagnetic disturbances

      • An effect of a geomagnetic storm on radio-wave propagation can be degraded high-latitude HF propagation.

      • HF radio communications are disturbed by the charged particles that reach the Earth from solar coronal holes.

      • It takes charged particles from Coronal Mass Ejections about 20 to 40 hours to affect radio-wave propagation on the Earth


    G3 radio wave propagation g3a6
    G3 … Radio Wave PropagationG3A

    • Propagation forecasting and indices

      • The solar flux index is a measure of the radio energy emitted by the sun.

      • The solar-flux index is a measure of solar activity at 10.7 cm.

      • Long-distance communication in the upper HF and lower VHF range has enhanced radio communications when sunspot numbers are high.


    G3 radio wave propagation g3a7
    G3 … Radio Wave PropagationG3A

    • Propagation forecasting and indices (cont)

      • The K-index is a measure of the short-term stability of the Earth’s magnetic field.

      • The A-index is an indicator of the long-term stability of the Earth’s geomagnetic field.

      • At any point in the solar cycle, the 20-meter band usually supports worldwide propagation during daylight hours.

      • If the HF radio-wave propagation (skip) is generally good on the 24-MHz and 28-MHz bands for several days, you might expect a similar condition to occur 28 days later.


    G3 radio wave propagation g3a8
    G3 … Radio Wave PropagationG3A

    • Propagation forecasting and indices (cont)


    G3 radio wave propagation g3a9
    G3 … Radio Wave PropagationG3A

    • Propagation forecasting and indices(cont)

      • Frequencies above 20 MHz are the least reliable for long distance communications during periods of low solar activity.

      • A possible benefit to radio communications resulting from periods of high geomagnetic activity is Aurora that can reflect VHF signals.

    Aurora Borealis


    G3 radio wave propagation g3b
    G3 … Radio Wave PropagationG3B

    • Maximum Usable Frequency

      • MUF stands for the Maximum Usable Frequency for communications between two points

      • The 15-meter band should offer the best chance for a successful contact if the maximum usable frequency (MUF) between the two stations is 22 MHz.

      • The 20-meter band should offer the best chance for a successful contact if the maximum usable frequency (MUF) between the two stations is 16 MHz.


    G3 radio wave propagation g3b1
    G3 … Radio Wave PropagationG3B

    • Critical & Maximum

      Usable Frequency

      • The frequency at which a signal sent vertically will pass right through the ionosphere is called the critical frequency.

      • The frequency at which communication just starts to fail is known as the Maximum Usable Frequency (MUF). It is generally three to five times the critical frequency, dependent upon the layer being used and the angle of incidence.


    G3 radio wave propagation g3b2
    G3 … Radio Wave PropagationG3B

    • Maximum Usable Frequency(cont)

      • For lowest attenuation when transmitting on HF, select a frequency just below the MUF.

      • A reliable way to determine if the maximum usable frequency (MUF) is high enough to support 28-MHz propagation between your station and Western Europe is to listen for signals on a 28 MHz international beacon.

      • Radio waves with frequencies below the maximum usable frequency (MUF) are usually bent back to the Earth after they are sent into the ionosphere.


    G3 radio wave propagation g3b3
    G3 … Radio Wave PropagationG3B

    • Maximum Usable Frequency(cont)

      • The factors that affect the maximum usable frequency (MUF) are:

        • Path distance and location

        • Time of day and season

        • Solar radiation and ionospheric disturbance

          [All of these choices are correct]

  • Lowest Usable Frequency

    • LUF stands for the Lowest Usable Frequency for communications between two points.

    • Radio waves with frequencies below the lowest usable frequency (LUF) are usually completely absorbed by the ionosphere


  • G3 radio wave propagation g3b4
    G3 … Radio Wave PropagationG3B

    • Propagation “hops”

      • The maximum distance along the Earth's surface that is normally covered in one hop using the F2 region is 2,500 miles.

      • The maximum distance along the Earth's surface that is normally covered in one hop using the E region is 1,200 miles.


    G3 radio wave propagation g3b5
    G3 … Radio Wave PropagationG3B

    • Propagation “hops” (cont)

      • When the lowest usable frequency (LUF) exceeds the maximum usable frequency (MUF), no HF radio frequency will support communications over the path.

      • A sky-wave signal will sound like a well-defined echo when it arrives at your receiver by both short path and long path propagation.

      • Short hop sky-wave propagation on the 10-meter band is a good indicator of the possibility of sky-wave propagation on the 6-meter band.


    G3 radio wave propagation g3c
    G3 … Radio Wave PropagationG3C

    • Ionospheric layers

      • The D layer of the ionosphere is closest to the surface of the Earth

      • The ionospheric D layer is the most absorbent of long skip signals during daylight hours on frequencies below 10 MHz

      • The F2 region be expected to reach its maximum height at your location at noon during the summer

      • The F2 region is mainly responsible for the longest distance radio wave propagation because it is the highest ionospheric region.

      • Ionospheric Absorption will be minimum near the maximum usable frequency (MUF).


    G3 radio wave propagation g3c1
    G3 … Radio Wave PropagationG3C

    • Critical angle and frequency

      • The term “critical angle” means the highest takeoff angle that will return a radio wave to the Earth under specific ionospheric conditions.


    G3 radio wave propagation g3c2
    G3 … Radio Wave PropagationG3C

    • HF Scatter

      • Long distance communication on the 40, 60, 80 and 160-meter bands are more difficult during the day because the D layer absorbs these frequencies during daylight hours.


    G3 radio wave propagation g3c3
    G3 … Radio Wave PropagationG3C

    • HF Scatter(cont)

      • HF scatter signals often sound distorted because energy is scattered into the skip zone through several radio wave paths.

      • A characteristic of HF scatter signals is that they have a wavering sound.

    Tropo Scatter

    Meteor Scatter


    G3 radio wave propagation g3c4
    G3 … Radio Wave PropagationG3C

    • HF Scatter(cont)

      • The HF scatter signals in the skip zone are usually weak because only a small part of the signal energy is scattered into the skip zone.

      • Scatter radio wave propagation allows a signal to be detected at a distance too far for ground wave propagation but too near for normal sky wave propagation.

      • An indication that signals heard on the HF bands are being received via scatter propagation can be when the signal is heard on a frequency above the maximum usable frequency.


    G3 radio wave propagation g3c5
    G3 … Radio Wave PropagationG3C

    • Near Vertical Incidence Sky waves

      • Near Vertical Incidence Sky-wave (NVIS), propagation is short distance HF propagation using high elevation angles


    G3 radio wave propagation g3c6
    G3 … Radio Wave PropagationG3C

    • Near Vertical Incidence Sky waves


    G3 radio wave propagation g3c7
    G3 … Radio Wave PropagationG3C

    • Dipole placement

      • A horizontal dipole antenna placed between 1/8 and 1/4 wavelength above the ground will be most effective for skip communications on 40 meters during the day.

    ⅛ - ¼ wavelength above ground


    G3 radio wave propagation g3c8
    G3 … Radio Wave PropagationG3C

    • Dipole placement


    Element 3 general class question pool
    Element 3 General Class Question Pool

    Sub-element G3

    Valid July 1, 2007

    Through

    June 30, 2011


    G3A01 What can be done at an amateur station to continue communications during a sudden ionospheric disturbance?

    • Try a higher frequency

    • Try the other sideband

    • Try a different antenna polarization

    • Try a different frequency shift


    G3A02 What effect does a Sudden Ionospheric Disturbance (SID) have on the daytime ionospheric propagation of HF radio waves?

    • It disrupts higher-latitude paths more than lower-latitude paths

    • It disrupts signals on lower frequencies more than those on higher frequencies

    • It disrupts communications via satellite more than direct communications

    • None, because only areas on the night side of the Earth are affected


    G3A03 How long does it take the increased ultraviolet and X-ray radiation from solar flares to affect radio-wave propagation on the Earth?

    • 28 days

    • Several hours depending on the position of the Earth in its orbit

    • Approximately 8 minutes

    • 20 to 40 hours after the radiation reaches the Earth


    G3a04 what is measured by the solar flux index
    G3A04 What is measured by the solar flux index? X-ray radiation from solar flares to affect radio-wave propagation on the Earth?

    • The density of the sun's magnetic field

    • The radio energy emitted by the sun

    • The number of sunspots on the side of the sun facing the Earth

    • A measure of the tilt of the Earth's ionosphere on the side toward the sun


    G3a05 what is the solar flux index
    G3A05 What is the solar-flux index? X-ray radiation from solar flares to affect radio-wave propagation on the Earth?

    • A measure of the highest frequency that is useful for ionospheric propagation between two points on the Earth

    • A count of sunspots which is adjusted for solar emissions

    • Another name for the American sunspot number

    • A measure of solar activity at 10.7 cm


    G3a06 what is a geomagnetic disturbance
    G3A06 What is a geomagnetic disturbance? X-ray radiation from solar flares to affect radio-wave propagation on the Earth?

    • A sudden drop in the solar-flux index

    • A shifting of the Earth's magnetic pole

    • Ripples in the ionosphere

    • A significant change in the Earth's magnetic field over a short period of time


    G3a07 which latitudes have propagation paths that are more sensitive to geomagnetic disturbances
    G3A07 Which latitudes have propagation paths that are more sensitive to geomagnetic disturbances?

    • Those greater than 45 degrees North or South latitude

    • Those between 5 and 45 degrees North or South latitude

    • Those at or very near to the equator

    • All paths are affected equally


    G3a08 what can be an effect of a geomagnetic storm on radio wave propagation
    G3A08 What can be an effect of a geomagnetic storm on radio-wave propagation?

    • Improved high-latitude HF propagation

    • Degraded high-latitude HF propagation

    • Improved ground-wave propagation

    • Improved chances of UHF ducting


    G3a09 what is the effect on radio communications when sunspot numbers are high
    G3A09 What is the effect on radio communications when sunspot numbers are high?

    • High-frequency radio signals become weak and distorted

    • Frequencies above 300 MHz become usable for long-distance communication

    • Long-distance communication in the upper HF and lower VHF range is enhanced

    • Long-distance communication in the upper HF and lower VHF range is diminished


    G3a10 what is the sunspot number
    G3A10 What is the sunspot number? sunspot numbers are high?

    • A measure of solar activity based on counting sunspots and sunspot groups

    • A 3 digit identifier which is used to track individual sunspots

    • A measure of the radio flux from the sun measured at 10.7 cm

    • A measure of the sunspot count based on radio flux measurements


    G3a11 how long is the typical sunspot cycle
    G3A11 How long is the typical sunspot cycle? sunspot numbers are high?

    • Approximately 8 minutes

    • Between 20 and 40 hours

    • Approximately 28 days

    • Approximately 11 years


    G3a12 what is the k index
    G3A12 What is the K-index? sunspot numbers are high?

    • An index of the relative position of sunspots on the surface of the sun

    • A measure of the short term stability of the Earth’s magnetic field

    • A measure of the stability of the sun's magnetic field

    • An index of solar radio flux measured at Boulder, Colorado


    G3a13 what is the a index
    G3A13 What is the A-index? sunspot numbers are high?

    • An index of the relative position of sunspots on the surface of the sun

    • The amount of polarization of the sun's electric field

    • An indicator of the long term stability of the Earth’s geomagnetic field

    • An index of solar radio flux measured at Boulder, Colorado


    G3A14 How are radio communications usually affected by the charged particles that reach the Earth from solar coronal holes?

    • HF communications are improved

    • HF communications are disturbed

    • VHF/UHF ducting is improved

    • VHF/UHF ducting is disturbed


    G3A15 How long does it take charged particles from Coronal Mass Ejections to affect radio-wave propagation on the Earth?

    • 28 days

    • 14 days

    • The effect is instantaneous

    • 20 to 40 hours


    G3A16 What is a possible benefit to radio communications resulting from periods of high geomagnetic activity?

    • Aurora that can reflect VHF signals

    • Higher signal strength for HF signals passing through the polar regions

    • Improved HF long path propagation

    • Reduced long delayed echoes


    G3A17 At what point in the solar cycle does the 20 meter band usually support worldwide propagation during daylight hours?

    • At the summer solstice

    • Only at the maximum point of the solar cycle

    • Only at the minimum point of the solar cycle

    • At any point in the solar cycle


    G3A18 If the HF radio-wave propagation (skip) is generally good on the 24-MHz and 28-MHz bands for several days, when might you expect a similar condition to occur?

    • 7 days later

    • 14 days later

    • 28 days later

    • 90 days later


    G3A19 Which frequencies are least reliable for long distance communications during periods of low solar activity?

    • Frequencies below 3.5 MHz

    • Frequencies near 3.5 MHz

    • Frequencies at or above 10 MHz

    • Frequencies above 20 MHz


    G3B01 Which band should offer the best chance for a successful contact if the maximum usable frequency (MUF) between the two stations is 22 MHz?

    • 10 meters

    • 15 meters

    • 20 meters

    • 40 meters


    G3B02 Which band should offer the best chance for a successful contact if the maximum usable frequency (MUF) between the two stations is 16 MHz?

    • 80 meters

    • 40 meters

    • 20 meters

    • 2 meters


    G3B03 Which of the following guidelines should be selected for lowest attenuation when transmitting on HF?

    • Select a frequency just below the MUF

    • Select a frequency just above the LUF

    • Select a frequency just below the critical frequency

    • Select a frequency just above the critical frequency


    G3B04 What is a reliable way to determine if the maximum usable frequency (MUF) is high enough to support 28-MHz propagation between your station and Western Europe?

    • Listen for signals on a 28 MHz international beacon

    • Send a series of dots on the 28 MHz band and listen for echoes from your signal

    • Check the strength of TV signals from Western Europe

    • Listen to WWV propagation signals on the 28 MHz band


    G3B05 What usually happens to radio waves with frequencies below the maximum usable frequency (MUF) when they are sent into the ionosphere?

    • They are bent back to the Earth

    • They pass through the ionosphere

    • They are completely absorbed by the ionosphere

    • They are bent and trapped in the ionosphere to circle the Earth


    G3b06 what usually happens to radio waves with frequencies below the lowest usable frequency luf
    G3B06 What usually happens to radio waves with frequencies below the lowest usable frequency (LUF)?

    • They are bent back to the Earth

    • They pass through the ionosphere

    • They are completely absorbed by the ionosphere

    • They are bent and trapped in the ionosphere to circle the Earth


    G3b07 what does luf stand for
    G3B07 What does LUF stand for? below the lowest usable frequency (LUF)?

    • The Lowest Usable Frequency for communications between two points

    • The Longest Universal Function for communications between two points

    • The Lowest Usable Frequency during a 24 hour period

    • The Longest Universal Function during a 24 hour period


    G3b08 what does muf stand for
    G3B08 What does MUF stand for? below the lowest usable frequency (LUF)?

    • The Minimum Usable Frequency for communications between two points

    • The Maximum Usable Frequency for communications between two points

    • The Minimum Usable Frequency during a 24 hour period

    • The Maximum Usable Frequency during a 24 hour period


    G3B09 What is the maximum distance along the Earth's surface that is normally covered in one hop using the F2 region?

    • 180 miles

    • 1,200 miles

    • 2,500 miles

    • 12,000 miles


    G3B10 What is the maximum distance along the Earth's surface that is normally covered in one hop using the E region?

    • 180 miles

    • 1,200 miles

    • 2,500 miles

    • 12,000 miles


    G3B11 What happens to HF propagation when the lowest usable frequency (LUF) exceeds the maximum usable frequency (MUF)?

    • No HF radio frequency will support communications over the path

    • HF communications over the path are enhanced at the frequency where the LUF and MUF are the same

    • Double hop propagation along the path is more common

    • Propagation over the path on all HF frequencies is enhanced


    G3b12 what factors affect the maximum usable frequency muf
    G3B12 What factors affect the maximum usable frequency (MUF)?

    • Path distance and location

    • Time of day and season

    • Solar radiation and ionospheric disturbance

    • All of these choices are correct


    G3B13 How might a sky-wave signal sound if it arrives at your receiver by both short path and long path propagation?

    • Periodic fading approximately every 10 seconds

    • Signal strength increased by 3 dB

    • The signal will be cancelled causing severe attenuation

    • A well-defined echo can be heard


    G3B14 Which of the following is a good indicator of the possibility of sky-wave propagation on the 6 meter band?

    • Short hop sky-wave propagation on the 10 meter band

    • Long hop sky-wave propagation on the 10 meter band

    • Severe attenuation of signals on the 10 meter band

    • Long delayed echoes on the 10 meter band


    G3c01 which of the following ionospheric layers is closest to the surface of the earth
    G3C01 Which of the following ionospheric layers is closest to the surface of the Earth?

    • The D layer

    • The E layer

    • The F1 layer

    • The F2 layer


    G3c02 when can the f2 region be expected to reach its maximum height at your location
    G3C02 When can the F2 region be expected to reach its maximum height at your location?

    • At noon during the summer

    • At midnight during the summer

    • At dusk in the spring and fall

    • At noon during the winter


    G3c03 why is the f2 region mainly responsible for the longest distance radio wave propagation
    G3C03 Why is the F2 region mainly responsible for the longest distance radio wave propagation?

    • Because it is the densest ionospheric layer

    • Because it does not absorb radio waves as much as other ionospheric regions

    • Because it is the highest ionospheric region

    • All of these choices are correct


    G3c04 what does the term critical angle mean as used in radio wave propagation
    G3C04 What does the term “critical angle” mean as used in radio wave propagation?

    • The long path azimuth of a distant station

    • The short path azimuth of a distant station

    • The lowest takeoff angle that will return a radio wave to the Earth under specific ionospheric conditions

    • The highest takeoff angle that will return a radio wave to the Earth under specific ionospheric conditions


    G3C05 Why is long distance communication on the 40, 60, 80 and 160 meter bands more difficult during the day?

    • The F layer absorbs these frequencies during daylight hours

    • The F layer is unstable during daylight hours

    • The D layer absorbs these frequencies during daylight hours

    • The E layer is unstable during daylight hours


    G3c06 what is a characteristic of hf scatter signals
    G3C06 What is a characteristic of HF scatter signals? and 160 meter bands more difficult during the day?

    • They have high intelligibility

    • They have a wavering sound

    • They have very large swings in signal strength

    • All of these choices are correct


    G3c07 what makes hf scatter signals often sound distorted
    G3C07 What makes HF scatter signals often sound distorted? and 160 meter bands more difficult during the day?

    • The ionospheric layer involved is unstable

    • Ground waves are absorbing much of the signal

    • The E-region is not present

    • Energy is scattered into the skip zone through several radio wave paths


    G3c08 why are hf scatter signals in the skip zone usually weak
    G3C08 Why are HF scatter signals in the skip zone usually weak?

    • Only a small part of the signal energy is scattered into the skip zone

    • Signals are scattered from the troposphere which is not a good reflector

    • Propagation is through ground waves which absorb most of the signal energy

    • Propagations is through ducts in F region which absorb most of the energy


    G3C09 What type of radio wave propagation allows a signal to be detected at a distance too far for ground wave propagation but too near for normal sky wave propagation?

    • Ground wave

    • Scatter

    • Sporadic-E skip

    • Short-path skip


    G3C10 Which of the following might be an indication that signals heard on the HF bands are being received via scatter propagation?

    • The communication is during a sunspot maximum

    • The communication is during a sudden ionospheric disturbance

    • The signal is heard on a frequency below the maximum usable frequency

    • The signal is heard on a frequency above the maximum usable frequency


    G3C11 Which of the following is true about ionospheric absorption near the maximum usable frequency (MUF)?

    • Absorption will be minimum

    • Absorption is greater for vertically polarized waves

    • Absorption approaches maximum

    • Absorption is greater for horizontally polarized waves


    G3C12 Which ionospheric layer is the most absorbent of long skip signals during daylight hours on frequencies below 10 MHz?

    • The F2 layer

    • The F1 layer

    • The E layer

    • The D layer


    G3c13 what is near vertical incidence sky wave nvis propagation
    G3C13 What is Near Vertical Incidence Sky-wave (NVIS) propagation?

    • Propagation near the MUF

    • Short distance HF propagation using high elevation angles

    • Long path HF propagation at sunrise and sunset

    • Double hop propagation near the LUF


    G3C14 Which of the following antennas will be most effective for skip communications on 40 meters during the day?

    • A vertical antenna

    • A horizontal dipole placed between 1/8 and 1/4 wavelength above the ground

    • A left-hand circularly polarized antenna

    • A right-hand circularly polarized antenna


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