G3 - RADIO WAVE PROPAGATION [3 Exam Questions - 3 Groups]

Radio Wave Propagation1

G3 - RADIO WAVE PROPAGATION G3 - RADIO WAVE PROPAGATION [3 Exam Questions - 3 Groups] [3 Exam Questions - 3 Groups]

G3AG3A Sunspots and solar radiation; ionospheric Sunspots and solar radiation; ionospheric disturbances; propagation forecasting and indices disturbances; propagation forecasting and indices

G3BG3B Maximum Usable Frequency; Lowest Usable Maximum Usable Frequency; Lowest Usable Frequency; propagation "hops" Frequency; propagation "hops"

G3CG3C Ionospheric layers; critical angle and frequency; Ionospheric layers; critical angle and frequency; HF scatter; Near Vertical Incidence Sky waves HF scatter; Near Vertical Incidence Sky waves


Ionospheric ProtectionIonospheric Protection

The ionosphere and magnetosphere protect us from The ionosphere and magnetosphere protect us from harmful radiation from the sunharmful radiation from the sun

G3A Sunspots and Solar RadiationG3A Sunspots and Solar Radiation

• It takes approx. 8 minutes for increased It takes approx. 8 minutes for increased ultraviolet and x-ray radiation from solar ultraviolet and x-ray radiation from solar flares to affect radio-wave propagationflares to affect radio-wave propagation

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

• The typical sunspot cycle is approximately 11 The typical sunspot cycle is approximately 11 years longyears long


G3A Ionospheric disturbancesG3A Ionospheric disturbances

• Try a higher frequency to continue Try a higher frequency to continue communications during a sudden ionospheric communications during a sudden ionospheric disturbancedisturbance

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

• Geomagnetic disturbance – significant change in Geomagnetic disturbance – significant change in the Earth’s magnetic field over a short periodthe Earth’s magnetic field over a short period

• Lattitudes, greater than 45 degrees North or Lattitudes, greater than 45 degrees North or South latitude, have propogation paths that are South latitude, have propogation paths that are more sensitive to geomagnetic disturbancesmore sensitive to geomagnetic disturbances


G3A Ionospheric disturbances cont’dG3A Ionospheric disturbances cont’d

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

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

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


G3A Propagation forecasting and G3A Propagation forecasting and indicesindices

• Solar flux indexSolar flux index• A measure of the radio energy emitted by the sunA measure of the radio energy emitted by the sun• Is a measure of solar activity at 10.7 cm (2800 MHz)Is a measure of solar activity at 10.7 cm (2800 MHz)

• Long-distance communication in the upper HF Long-distance communication in the upper HF and lower VHF range is enhanced when and lower VHF range is enhanced when sunspot numbers are highsunspot numbers are high

• K-index – a measure of the short-term K-index – a measure of the short-term stability of the Earth’s magnetic fieldstability of the Earth’s magnetic field

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


G3A Propagation cont’dG3A Propagation cont’d* 20-meter band usually supports worldwide * 20-meter band usually supports worldwide

propagation during daylight hours, at any propagation during daylight hours, at any point during daylight hourspoint during daylight hours

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

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

• High periods of geomagnetic activity may High periods of geomagnetic activity may create and Aurora that can reflect VHF create and Aurora that can reflect VHF signalssignals



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

A.A. Try a higher frequencyTry a higher frequencyB.B. Try the other sidebandTry the other sidebandC.C. Try a different antenna polarizationTry a different antenna polarizationD.D. Try a different frequency shiftTry a different frequency shift


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

A.A. Try a higher frequencyTry a higher frequencyB.B. Try the other sidebandTry the other sidebandC.C. Try a different antenna polarizationTry a different antenna polarizationD.D. Try a different frequency shiftTry a different frequency shift


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

A.A. It disrupts higher-latitude paths more than lower-It disrupts higher-latitude paths more than lower-latitude pathslatitude paths

B.B. It disrupts signals on lower frequencies more than It disrupts signals on lower frequencies more than those on higher frequenciesthose on higher frequencies

C.C. It disrupts communications via satellite more than It disrupts communications via satellite more than direct communicationsdirect communications

D.D. None, because only areas on the night side of the None, because only areas on the night side of the Earth are affectedEarth are affected


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

A.A. It disrupts higher-latitude paths more than lower-It disrupts higher-latitude paths more than lower-latitude pathslatitude paths

B.B. It disrupts signals on lower frequencies It disrupts signals on lower frequencies more than those on higher frequenciesmore than those on higher frequencies

C.C. It disrupts communications via satellite more than It disrupts communications via satellite more than direct communicationsdirect communications

D.D. None, because only areas on the night side of the None, because only areas on the night side of the Earth are affectedEarth are affected


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

A.A. 28 days28 daysB.B. Several hours depending on the position of the Several hours depending on the position of the

Earth in its orbitEarth in its orbitC.C. Approximately 8 minutesApproximately 8 minutesD.D. 20 to 40 hours after the radiation reaches the Earth20 to 40 hours after the radiation reaches the Earth


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

A.A. 28 days28 daysB.B. Several hours depending on the position of the Several hours depending on the position of the

Earth in its orbitEarth in its orbitC.C. Approximately 8 minutesApproximately 8 minutes

D.D. 20 to 40 hours after the radiation reaches the Earth20 to 40 hours after the radiation reaches the Earth


G3A04 What is measured by the solar G3A04 What is measured by the solar flux index?flux index?

A.A. The density of the sun's magnetic fieldThe density of the sun's magnetic fieldB.B. The radio energy emitted by the sunThe radio energy emitted by the sunC.C. The number of sunspots on the side of the sun The number of sunspots on the side of the sun

facing the Earthfacing the EarthD.D. A measure of the tilt of the Earth's ionosphere on A measure of the tilt of the Earth's ionosphere on

the side toward the sunthe side toward the sun


G3A04 What is measured by the solar G3A04 What is measured by the solar flux index?flux index?

A.A. The density of the sun's magnetic fieldThe density of the sun's magnetic fieldB.B. The radio energy emitted by the sunThe radio energy emitted by the sun

C.C. The number of sunspots on the side of the sun The number of sunspots on the side of the sun facing the Earthfacing the Earth

D.D. A measure of the tilt of the Earth's ionosphere on A measure of the tilt of the Earth's ionosphere on the side toward the sunthe side toward the sun


G3A05 What is the solar-flux index?G3A05 What is the solar-flux index?

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

B.B. A count of sunspots which is adjusted for solar A count of sunspots which is adjusted for solar emissionsemissions

C.C. Another name for the American sunspot numberAnother name for the American sunspot numberD.D. A measure of solar activity at 10.7 cmA measure of solar activity at 10.7 cm


G3A05 What is the solar-flux index?G3A05 What is the solar-flux index?

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

B.B. A count of sunspots which is adjusted for solar A count of sunspots which is adjusted for solar emissionsemissions

C.C. Another name for the American sunspot numberAnother name for the American sunspot numberD.D. A measure of solar activity at 10.7 cmA measure of solar activity at 10.7 cm


G3A06 What is a geomagnetic G3A06 What is a geomagnetic disturbance?disturbance?

A.A. A sudden drop in the solar-flux indexA sudden drop in the solar-flux indexB.B. A shifting of the Earth's magnetic poleA shifting of the Earth's magnetic poleC.C. Ripples in the ionosphereRipples in the ionosphereD.D. A significant change in the Earth's magnetic field A significant change in the Earth's magnetic field

over a short period of timeover a short period of time


G3A06 What is a geomagnetic G3A06 What is a geomagnetic disturbance?disturbance?

A.A. A sudden drop in the solar-flux indexA sudden drop in the solar-flux indexB.B. A shifting of the Earth's magnetic poleA shifting of the Earth's magnetic poleC.C. Ripples in the ionosphereRipples in the ionosphere

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


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

A.A. Those greater than 45 degrees North or South Those greater than 45 degrees North or South latitudelatitude

B.B. Those between 5 and 45 degrees North or South Those between 5 and 45 degrees North or South latitudelatitude

C.C. Those at or very near to the equatorThose at or very near to the equatorD.D. All paths are affected equallyAll paths are affected equally


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

A.A. Those greater than 45 degrees North or Those greater than 45 degrees North or South latitudeSouth latitude

B.B. Those between 5 and 45 degrees North or South Those between 5 and 45 degrees North or South latitudelatitude

C.C. Those at or very near to the equatorThose at or very near to the equatorD.D. All paths are affected equallyAll paths are affected equally


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

A.A. Improved high-latitude HF propagationImproved high-latitude HF propagationB.B. Degraded high-latitude HF propagationDegraded high-latitude HF propagationC.C. Improved ground-wave propagationImproved ground-wave propagationD.D. Improved chances of UHF ductingImproved chances of UHF ducting


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

A.A. Improved high-latitude HF propagationImproved high-latitude HF propagationB.B. Degraded high-latitude HF propagationDegraded high-latitude HF propagation

C.C. Improved ground-wave propagationImproved ground-wave propagationD.D. Improved chances of UHF ductingImproved chances of UHF ducting


SunspotsSunspots

Sunspot number refers to the number of sunspots Sunspot number refers to the number of sunspots and groupsand groupsThe higher the sunspot count, the more ionizationThe higher the sunspot count, the more ionizationThus, higher sunspot counts support a higher Thus, higher sunspot counts support a higher Maximum Usable Frequency (MUF)Maximum Usable Frequency (MUF)


Sunspot CycleSunspot Cycle

Sunspots peak during 11-year cyclesSunspots peak during 11-year cycles

http://upload.wikimedia.org/wikipedia/commons/2/28/Sunspot_Numbers.png

Sunspot ForecastSunspot Forecast



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

A.A. High-frequency radio signals become weak and High-frequency radio signals become weak and distorteddistorted

B.B. Frequencies above 300 MHz become usable for Frequencies above 300 MHz become usable for long-distance communicationlong-distance communication

C.C. Long-distance communication in the upper HF and Long-distance communication in the upper HF and lower VHF range is enhancedlower VHF range is enhanced

D.D. Long-distance communication in the upper HF and Long-distance communication in the upper HF and lower VHF range is diminishedlower VHF range is diminished


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

A.A. High-frequency radio signals become weak and High-frequency radio signals become weak and distorteddistorted

B.B. Frequencies above 300 MHz become usable for Frequencies above 300 MHz become usable for long-distance communicationlong-distance communication

C.C. Long-distance communication in the upper Long-distance communication in the upper HF and lower VHF range is enhancedHF and lower VHF range is enhanced

D.D. Long-distance communication in the upper HF and Long-distance communication in the upper HF and lower VHF range is diminishedlower VHF range is diminished


G3A10 What is the sunspot number?G3A10 What is the sunspot number?

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

B.B. A 3 digit identifier which is used to track individual A 3 digit identifier which is used to track individual sunspotssunspots

C.C. A measure of the radio flux from the sun measured A measure of the radio flux from the sun measured at 10.7 cmat 10.7 cm

D.D. A measure of the sunspot count based on radio flux A measure of the sunspot count based on radio flux measurementsmeasurements


G3A10 What is the sunspot number?G3A10 What is the sunspot number?

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

B.B. A 3 digit identifier which is used to track individual A 3 digit identifier which is used to track individual sunspotssunspots

C.C. A measure of the radio flux from the sun measured A measure of the radio flux from the sun measured at 10.7 cmat 10.7 cm

D.D. A measure of the sunspot count based on radio flux A measure of the sunspot count based on radio flux measurementsmeasurements


G3A11 How long is the typical sunspot G3A11 How long is the typical sunspot cycle?cycle?

A.A. Approximately 8 minutesApproximately 8 minutesB.B. Between 20 and 40 hoursBetween 20 and 40 hoursC.C. Approximately 28 daysApproximately 28 daysD.D. Approximately 11 yearsApproximately 11 years


G3A11 How long is the typical sunspot G3A11 How long is the typical sunspot cycle?cycle?

A.A. Approximately 8 minutesApproximately 8 minutesB.B. Between 20 and 40 hoursBetween 20 and 40 hoursC.C. Approximately 28 daysApproximately 28 days

D.D. Approximately 11 yearsApproximately 11 years


G3A12 What is the K-index?G3A12 What is the K-index?

A.A. An index of the relative position of sunspots on the An index of the relative position of sunspots on the surface of the sunsurface of the sun

B.B. A measure of the short term stability of the Earth's A measure of the short term stability of the Earth's magnetic fieldmagnetic field

C.C. A measure of the stability of the sun's magnetic A measure of the stability of the sun's magnetic fieldfield

D.D. An index of solar radio flux measured at Boulder, An index of solar radio flux measured at Boulder, ColoradoColorado


G3A12 What is the K-index?G3A12 What is the K-index?


B.B. A measure of the short term stability of A measure of the short term stability of the Earth's magnetic fieldthe Earth's magnetic field

C.C. A measure of the stability of the sun's magnetic A measure of the stability of the sun's magnetic fieldfield



G3A13 What is the A-index?G3A13 What is the A-index?


B.B. The amount of polarization of the sun's electric fieldThe amount of polarization of the sun's electric fieldC.C. An indicator of the long term stability of the Earth's An indicator of the long term stability of the Earth's

geomagnetic fieldgeomagnetic fieldD.D. An index of solar radio flux measured at Boulder, An index of solar radio flux measured at Boulder,

ColoradoColorado


G3A13 What is the A-index?G3A13 What is the A-index?


B.B. The amount of polarization of the sun's electric fieldThe amount of polarization of the sun's electric fieldC.C. An indicator of the long term stability of An indicator of the long term stability of the Earth's geomagnetic fieldthe Earth's geomagnetic field



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

A.A. HF communications are improvedHF communications are improvedB.B. HF communications are disturbedHF communications are disturbedC.C. VHF/UHF ducting is improvedVHF/UHF ducting is improvedD.D. VHF/UHF ducting is disturbedVHF/UHF ducting is disturbed


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

A.A. HF communications are improvedHF communications are improvedB.B. HF communications are disturbedHF communications are disturbed

C.C. VHF/UHF ducting is improvedVHF/UHF ducting is improvedD.D. VHF/UHF ducting is disturbedVHF/UHF ducting is disturbed


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

A.A. 28 days28 daysB.B. 14 days14 daysC.C. The effect is instantaneousThe effect is instantaneousD.D. 20 to 40 hours20 to 40 hours


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

A.A. 28 days28 daysB.B. 14 days14 daysC.C. The effect is instantaneousThe effect is instantaneous

D.D. 20 to 40 hours20 to 40 hours


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

A.A. Aurora that can reflect VHF signalsAurora that can reflect VHF signalsB.B. Higher signal strength for HF signals passing Higher signal strength for HF signals passing

through the polar regionsthrough the polar regionsC.C. Improved HF long path propagationImproved HF long path propagationD.D. Reduced long delayed echoesReduced long delayed echoes


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

A.A. Aurora that can reflect VHF signalsAurora that can reflect VHF signalsB.B. Higher signal strength for HF signals passing Higher signal strength for HF signals passing

through the polar regionsthrough the polar regionsC.C. Improved HF long path propagationImproved HF long path propagationD.D. Reduced long delayed echoesReduced long delayed echoes

Maximum usable frequency (MUF)Maximum usable frequency (MUF)

• 15-meter band should offer the best chance 15-meter band should offer the best chance of communication between two points if the of communication between two points if the maximum usable frequency (MUF) between maximum usable frequency (MUF) between the two stations is 22 MHzthe two stations is 22 MHz

• 20-meter band should offer the best chance 20-meter band should offer the best chance of communication between two points if the of communication between two points if the maximum usable frequency (MUF) between maximum usable frequency (MUF) between the two stations is 16 MHzthe two stations is 16 MHz


G3B Maximum usable frequency (MUF) G3B Maximum usable frequency (MUF) cont’dcont’d

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

• A reliable way to determine if the MUF is high A reliable way to determine if the MUF is high enough to support 28-MHz propagation enough to support 28-MHz propagation between your station and Western Europe is between your station and Western Europe is to listen on a 28-MHz international beaconto listen on a 28-MHz international beacon

• Radio waves with frequencies below the MUF Radio waves with frequencies below the MUF are usually bent back to the Earth after they are usually bent back to the Earth after they are sent into the ionosphereare sent into the ionosphere


G3B MUF and LUFG3B MUF and LUF

• The factors that affect the MUF are:The factors that affect the MUF are:• Path distance and locationPath distance and location• Time of day and seasonTime of day and season• Solar radiation and ionospheric disturbanceSolar radiation and ionospheric disturbance

• LUF stands for lowest usable frequency LUF stands for lowest usable frequency between two pointsbetween two points

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


G3B Propagation “hops”G3B Propagation “hops”

• Maximum distance along the Earth’s surface Maximum distance along the Earth’s surface that is normally covered in one hop:that is normally covered in one hop:• Using the F2 region is Using the F2 region is 2,500 miles2,500 miles• Using the E region is Using the E region is 1,200 miles1,200 miles

• When the LUF exceeds the MUF, no HF radio When the LUF exceeds the MUF, no HF radio frequency will support communication over the frequency will support communication over the pathpath

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

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



Ionospheric LayersIonospheric Layers


Critical AngleCritical Angle


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

A.A. At the summer solsticeAt the summer solsticeB.B. Only at the maximum point of the solar cycleOnly at the maximum point of the solar cycleC.C. Only at the minimum point of the solar cycleOnly at the minimum point of the solar cycleD.D. At any point in the solar cycleAt any point in the solar cycle


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

A.A. At the summer solsticeAt the summer solsticeB.B. Only at the maximum point of the solar cycleOnly at the maximum point of the solar cycleC.C. Only at the minimum point of the solar cycleOnly at the minimum point of the solar cycle

D.D. At any point in the solar cycleAt any point in the solar cycle


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

A.A. 7 days later7 days laterB.B. 14 days later14 days laterC.C. 28 days later28 days laterD.D. 90 days later90 days later


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

A.A. 7 days later7 days laterB.B. 14 days later14 days later

C.C. 28 days later28 days laterD.D. 90 days later90 days later


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

A.A. Frequencies below 3.5 MHzFrequencies below 3.5 MHzB.B. Frequencies near 3.5 MHzFrequencies near 3.5 MHzC.C. Frequencies at or above 10 MHzFrequencies at or above 10 MHzD.D. Frequencies above 20 MHzFrequencies above 20 MHz


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

A.A. Frequencies below 3.5 MHzFrequencies below 3.5 MHzB.B. Frequencies near 3.5 MHzFrequencies near 3.5 MHzC.C. Frequencies at or above 10 MHzFrequencies at or above 10 MHz

D.D. Frequencies above 20 MHzFrequencies above 20 MHz


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

A.A. 10 meters10 metersB.B. 15 meters15 metersC.C. 20 meters20 metersD.D. 40 meters40 meters



A.A. 10 meters10 metersB.B. 15 meters15 meters

C.C. 20 meters20 metersD.D. 40 meters40 meters



A.A. 80 meters80 metersB.B. 40 meters40 metersC.C. 20 meters20 metersD.D. 2 meters2 meters



A.A. 80 meters80 metersB.B. 40 meters40 meters

C.C. 20 meters20 metersD.D. 2 meters2 meters


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

A.A. Select a frequency just below the MUFSelect a frequency just below the MUFB.B. Select a frequency just above the LUFSelect a frequency just above the LUFC.C. Select a frequency just below the critical frequencySelect a frequency just below the critical frequencyD.D. Select a frequency just above the critical frequencySelect a frequency just above the critical frequency


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

A.A. Select a frequency just below the MUFSelect a frequency just below the MUFB.B. Select a frequency just above the LUFSelect a frequency just above the LUFC.C. Select a frequency just below the critical frequencySelect a frequency just below the critical frequencyD.D. Select a frequency just above the critical frequencySelect a frequency just above the critical frequency


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

A.A. Listen for signals on a 28 MHz international beaconListen for signals on a 28 MHz international beaconB.B. Send a series of dots on the 28 MHz band and listen Send a series of dots on the 28 MHz band and listen

for echoes from your signalfor echoes from your signalC.C. Check the strength of TV signals from Western Check the strength of TV signals from Western

EuropeEuropeD.D. Listen to WWV propagation signals on the 28 MHz Listen to WWV propagation signals on the 28 MHz

bandband


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

A.A. Listen for signals on a 28 MHz Listen for signals on a 28 MHz international beaconinternational beacon

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

C.C. Check the strength of TV signals from Western Check the strength of TV signals from Western EuropeEurope

D.D. Listen to WWV propagation signals on the 28 MHz Listen to WWV propagation signals on the 28 MHz bandband


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

A.A. They are bent back to the EarthThey are bent back to the EarthB.B. They pass through the ionosphereThey pass through the ionosphereC.C. They are completely absorbed by the ionosphereThey are completely absorbed by the ionosphereD.D. They are bent and trapped in the ionosphere to They are bent and trapped in the ionosphere to

circle the Earthcircle the Earth


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




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




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

A.A. They are bent back to the EarthThey are bent back to the EarthB.B. They pass through the ionosphereThey pass through the ionosphere

C.C. They are completely absorbed by the They are completely absorbed by the ionosphereionosphere

D.D. They are bent and trapped in the ionosphere to They are bent and trapped in the ionosphere to circle the Earthcircle the Earth


G3B07 What does LUF stand for?G3B07 What does LUF stand for?

A.A. The Lowest Usable Frequency for communications The Lowest Usable Frequency for communications between two pointsbetween two points

B.B. The Longest Universal Function for communications The Longest Universal Function for communications between two pointsbetween two points

C.C. The Lowest Usable Frequency during a 24 hour The Lowest Usable Frequency during a 24 hour periodperiod

D.D. The Longest Universal Function during a 24 hour The Longest Universal Function during a 24 hour periodperiod


G3B07 What does LUF stand for?G3B07 What does LUF stand for?

A.A. The Lowest Usable Frequency for The Lowest Usable Frequency for communications between two pointscommunications between two points

B.B. The Longest Universal Function for communications The Longest Universal Function for communications between two pointsbetween two points

C.C. The Lowest Usable Frequency during a 24 hour The Lowest Usable Frequency during a 24 hour periodperiod

D.D. The Longest Universal Function during a 24 hour The Longest Universal Function during a 24 hour periodperiod


G3B08 What does MUF stand for?G3B08 What does MUF stand for?

A.A. The Minimum Usable Frequency for communications The Minimum Usable Frequency for communications between two pointsbetween two points

B.B. The Maximum Usable Frequency for The Maximum Usable Frequency for communications between two pointscommunications between two points

C.C. The Minimum Usable Frequency during a 24 hour The Minimum Usable Frequency during a 24 hour periodperiod

D.D. The Maximum Usable Frequency during a 24 hour The Maximum Usable Frequency during a 24 hour periodperiod


G3B08 What does MUF stand for?G3B08 What does MUF stand for?

A.A. The Minimum Usable Frequency for communications The Minimum Usable Frequency for communications between two pointsbetween two points

B.B. The Maximum Usable Frequency for The Maximum Usable Frequency for communications between two pointscommunications between two points

C.C. The Minimum Usable Frequency during a 24 hour The Minimum Usable Frequency during a 24 hour periodperiod

D.D. The Maximum Usable Frequency during a 24 hour The Maximum Usable Frequency during a 24 hour periodperiod


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

A.A. 180 miles180 milesB.B. 1,200 miles1,200 milesC.C. 2,500 miles2,500 milesD.D. 12,000 miles12,000 miles


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

A.A. 180 miles180 milesB.B. 1,200 miles1,200 miles

C.C. 2,500 miles2,500 milesD.D. 12,000 miles12,000 miles


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

A.A. 180 miles180 milesB.B. 1,200 miles1,200 milesC.C. 2,500 miles2,500 milesD.D. 12,000 miles12,000 miles


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

A.A. 180 miles180 milesB.B. 1,200 miles1,200 miles

C.C. 2,500 miles2,500 milesD.D. 12,000 miles12,000 miles


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

A.A. No HF radio frequency will support communications No HF radio frequency will support communications over the pathover the path

B.B. HF communications over the path are enhanced at HF communications over the path are enhanced at the frequency where the LUF and MUF are the samethe frequency where the LUF and MUF are the same

C.C. Double hop propagation along the path is more Double hop propagation along the path is more commoncommon

D.D. Propagation over the path on all HF frequencies is Propagation over the path on all HF frequencies is enhancedenhanced


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

A.A. No HF radio frequency will support No HF radio frequency will support communications over the pathcommunications over the path

B.B. HF communications over the path are enhanced at HF communications over the path are enhanced at the frequency where the LUF and MUF are the samethe frequency where the LUF and MUF are the same

C.C. Double hop propagation along the path is more Double hop propagation along the path is more commoncommon

D.D. Propagation over the path on all HF frequencies is Propagation over the path on all HF frequencies is enhancedenhanced


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

A.A. Path distance and locationPath distance and locationB.B. Time of day and seasonTime of day and seasonC.C. Solar radiation and ionospheric disturbanceSolar radiation and ionospheric disturbanceD.D. All of these choices are correctAll of these choices are correct


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

A.A. Path distance and locationPath distance and locationB.B. Time of day and seasonTime of day and seasonC.C. Solar radiation and ionospheric disturbanceSolar radiation and ionospheric disturbance

D.D. All of these choices are correctAll of these choices are correct


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

A.A. Periodic fading approximately every 10 secondsPeriodic fading approximately every 10 secondsB.B. Signal strength increased by 3 dBSignal strength increased by 3 dBC.C. The signal will be cancelled causing severe The signal will be cancelled causing severe

attenuationattenuationD.D. A well-defined echo can be heardA well-defined echo can be heard


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

A.A. Periodic fading approximately every 10 secondsPeriodic fading approximately every 10 secondsB.B. Signal strength increased by 3 dBSignal strength increased by 3 dBC.C. The signal will be cancelled causing severe The signal will be cancelled causing severe

attenuationattenuationD.D. A well-defined echo can be heardA well-defined echo can be heard


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

A.A. Short hop sky-wave propagation on the 10 meter Short hop sky-wave propagation on the 10 meter bandband

B.B. Long hop sky-wave propagation on the 10 meter Long hop sky-wave propagation on the 10 meter bandband

C.C. Severe attenuation of signals on the 10 meter bandSevere attenuation of signals on the 10 meter bandD.D. Long delayed echoes on the 10 meter bandLong delayed echoes on the 10 meter band


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

A.A. Short hop sky-wave propagation on the 10 Short hop sky-wave propagation on the 10 meter bandmeter band

B.B. Long hop sky-wave propagation on the 10 meter Long hop sky-wave propagation on the 10 meter bandband

C.C. Severe attenuation of signals on the 10 meter bandSevere attenuation of signals on the 10 meter bandD.D. Long delayed echoes on the 10 meter bandLong delayed echoes on the 10 meter band

G3C Ionospheric layersG3C Ionospheric layers• D layer of the ionosphereD layer of the ionosphere

• Closest to the surface of the EarthClosest to the surface of the Earth• Most absorbent of long skip signals during daylight Most absorbent of long skip signals during daylight

hours on frequencies below 10 MHzhours on frequencies below 10 MHz• F2 regionF2 region

• Expected to reach its maximum height at your location Expected to reach its maximum height at your location at noon during the summerat noon during the summer

• Mainly responsible for the longest distance radio wave Mainly responsible for the longest distance radio wave propagation because it is the highest ionospheric regionpropagation because it is the highest ionospheric region

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

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


G3C HF ScatterG3C HF Scatter• Long distance communications on 40,60,80 Long distance communications on 40,60,80

and 160-meter bands are more difficult and 160-meter bands are more difficult during the day because the D layer absorbs during the day because the D layer absorbs these frequencies during daylight hoursthese frequencies during daylight hours

• HF scatter signalsHF scatter signals• OneOne characteristic is that they have a wavering characteristic is that they have a wavering

soundsound• Often sound distorted because energy is Often sound distorted because energy is

scattered into the skip zone through radio wave scattered into the skip zone through radio wave pathspaths

• In the skip zone, they are usually weak because In the skip zone, they are usually weak because only a small part of the signal energy is scattered only a small part of the signal energy is scattered into the skip zoneinto the skip zone


G3C HF scatter cont’dG3C HF scatter cont’d

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

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


G3C Near Vertical Incidence Sky waves G3C Near Vertical Incidence Sky waves (NVIS)(NVIS)

• NVIS propagation is short distance HF NVIS propagation is short distance HF propagation using high elevation anglespropagation using high elevation angles

• A horizontal dipole antenna placed between A horizontal dipole antenna placed between 1/8 and ¼ wavelength above the ground 1/8 and ¼ wavelength above the ground will be most effective for skip will be most effective for skip communications on 40 meters during the daycommunications on 40 meters during the day



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

A.A. The D layerThe D layerB.B. The E layerThe E layerC.C. The F1 layerThe F1 layerD.D. The F2 layerThe F2 layer


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

A.A. The D layerThe D layerB.B. The E layerThe E layerC.C. The F1 layerThe F1 layerD.D. The F2 layerThe F2 layer


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

A.A. At noon during the summerAt noon during the summerB.B. At midnight during the summerAt midnight during the summerC.C. At dusk in the spring and fallAt dusk in the spring and fallD.D. At noon during the winterAt noon during the winter


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

A.A. At noon during the summerAt noon during the summerB.B. At midnight during the summerAt midnight during the summerC.C. At dusk in the spring and fallAt dusk in the spring and fallD.D. At noon during the winterAt noon during the winter


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

A.A. Because it is the densest ionospheric layerBecause it is the densest ionospheric layerB.B. Because it does not absorb radio waves as much as Because it does not absorb radio waves as much as

other ionospheric regionsother ionospheric regionsC.C. Because it is the highest ionospheric regionBecause it is the highest ionospheric regionD.D. All of these choices are correctAll of these choices are correct


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

A.A. Because it is the densest ionospheric layerBecause it is the densest ionospheric layerB.B. Because it does not absorb radio waves as much as Because it does not absorb radio waves as much as

other ionospheric regionsother ionospheric regionsC.C. Because it is the highest ionospheric Because it is the highest ionospheric regionregion

D.D. All of these choices are correctAll of these choices are correct


G3C04 What does the term "critical G3C04 What does the term "critical angle" mean as used in radio wave angle" mean as used in radio wave propagation?propagation?

A.A. The long path azimuth of a distant stationThe long path azimuth of a distant stationB.B. The short path azimuth of a distant stationThe short path azimuth of a distant stationC.C. The lowest takeoff angle that will return a radio The lowest takeoff angle that will return a radio

wave to the Earth under specific ionospheric wave to the Earth under specific ionospheric conditionsconditions

D.D. The highest takeoff angle that will return a radio The highest takeoff angle that will return a radio wave to the Earth under specific ionospheric wave to the Earth under specific ionospheric conditionsconditions


G3C04 What does the term "critical G3C04 What does the term "critical angle" mean as used in radio wave angle" mean as used in radio wave propagation?propagation?

A.A. The long path azimuth of a distant stationThe long path azimuth of a distant stationB.B. The short path azimuth of a distant stationThe short path azimuth of a distant stationC.C. The lowest takeoff angle that will return a radio The lowest takeoff angle that will return a radio

wave to the Earth under specific ionospheric wave to the Earth under specific ionospheric conditionsconditions

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


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

A.A. The F layer absorbs these frequencies during The F layer absorbs these frequencies during daylight hoursdaylight hours

B.B. The F layer is unstable during daylight hoursThe F layer is unstable during daylight hoursC.C. The D layer absorbs these frequencies during The D layer absorbs these frequencies during

daylight hoursdaylight hoursD.D. The E layer is unstable during daylight hoursThe E layer is unstable during daylight hours


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

A.A. The F layer absorbs these frequencies during The F layer absorbs these frequencies during daylight hoursdaylight hours

B.B. The F layer is unstable during daylight hoursThe F layer is unstable during daylight hoursC.C. The D layer absorbs these frequencies The D layer absorbs these frequencies during daylight hoursduring daylight hours

D.D. The E layer is unstable during daylight hoursThe E layer is unstable during daylight hours


G3C06 What is a characteristic of HF G3C06 What is a characteristic of HF scatter signals?scatter signals?

A.A. They have high intelligibilityThey have high intelligibilityB.B. They have a wavering soundThey have a wavering soundC.C. They have very large swings in signal strengthThey have very large swings in signal strengthD.D. All of these choices are correctAll of these choices are correct


G3C06 What is a characteristic of HF G3C06 What is a characteristic of HF scatter signals?scatter signals?

A.A. They have high intelligibilityThey have high intelligibilityB.B. They have a wavering soundThey have a wavering sound

C.C. They have very large swings in signal strengthThey have very large swings in signal strengthD.D. All of these choices are correctAll of these choices are correct


G3C07 What makes HF scatter signals G3C07 What makes HF scatter signals often sound distorted?often sound distorted?

A.A. The ionospheric layer involved is unstableThe ionospheric layer involved is unstableB.B. Ground waves are absorbing much of the signalGround waves are absorbing much of the signalC.C. The E-region is not presentThe E-region is not presentD.D. Energy is scattered into the skip zone through Energy is scattered into the skip zone through

several radio wave pathsseveral radio wave paths


G3C07 What makes HF scatter signals G3C07 What makes HF scatter signals often sound distorted?often sound distorted?

A.A. The ionospheric layer involved is unstableThe ionospheric layer involved is unstableB.B. Ground waves are absorbing much of the signalGround waves are absorbing much of the signalC.C. The E-region is not presentThe E-region is not present

D.D. Energy is scattered into the skip zone Energy is scattered into the skip zone through several radio wave pathsthrough several radio wave paths


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

A.A. Only a small part of the signal energy is scattered Only a small part of the signal energy is scattered into the skip zoneinto the skip zone

B.B. Signals are scattered from the troposphere which is Signals are scattered from the troposphere which is not a good reflectornot a good reflector

C.C. Propagation is through ground waves which absorb Propagation is through ground waves which absorb most of the signal energymost of the signal energy

D.D. Propagations is through ducts in F region which Propagations is through ducts in F region which absorb most of the energyabsorb most of the energy


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

A.A. Only a small part of the signal energy is Only a small part of the signal energy is scattered into the skip zonescattered into the skip zone

B.B. Signals are scattered from the troposphere which is Signals are scattered from the troposphere which is not a good reflectornot a good reflector

C.C. Propagation is through ground waves which absorb Propagation is through ground waves which absorb most of the signal energymost of the signal energy

D.D. Propagations is through ducts in F region which Propagations is through ducts in F region which absorb most of the energyabsorb most of the energy


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

A.A. Ground waveGround waveB.B. ScatterScatterC.C. Sporadic-E skipSporadic-E skipD.D. Short-path skipShort-path skip


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

A.A. Ground waveGround waveB.B. ScatterScatter

C.C. Sporadic-E skipSporadic-E skipD.D. Short-path skipShort-path skip


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

A.A. The communication is during a sunspot maximumThe communication is during a sunspot maximumB.B. The communication is during a sudden ionospheric The communication is during a sudden ionospheric

disturbancedisturbanceC.C. The signal is heard on a frequency below the The signal is heard on a frequency below the

maximum usable frequencymaximum usable frequencyD.D. The signal is heard on a frequency above the The signal is heard on a frequency above the

maximum usable frequencymaximum usable frequency


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

A.A. The communication is during a sunspot maximumThe communication is during a sunspot maximumB.B. The communication is during a sudden ionospheric The communication is during a sudden ionospheric

disturbancedisturbanceC.C. The signal is heard on a frequency below the The signal is heard on a frequency below the

maximum usable frequencymaximum usable frequencyD.D. The signal is heard on a frequency above The signal is heard on a frequency above the maximum usable frequencythe maximum usable frequency


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

A.A. Absorption will be minimumAbsorption will be minimumB.B. Absorption is greater for vertically polarized wavesAbsorption is greater for vertically polarized wavesC.C. Absorption approaches maximumAbsorption approaches maximumD.D. Absorption is greater for horizontally polarized Absorption is greater for horizontally polarized

waveswaves


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

A.A. Absorption will be minimumAbsorption will be minimumB.B. Absorption is greater for vertically polarized wavesAbsorption is greater for vertically polarized wavesC.C. Absorption approaches maximumAbsorption approaches maximumD.D. Absorption is greater for horizontally polarized Absorption is greater for horizontally polarized

waveswaves


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

A.A. The F2 layerThe F2 layerB.B. The F1 layerThe F1 layerC.C. The E layerThe E layerD.D. The D layerThe D layer


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

A.A. The F2 layerThe F2 layerB.B. The F1 layerThe F1 layerC.C. The E layerThe E layer

D.D. The D layerThe D layer


G3C13 What is Near Vertical Incidence G3C13 What is Near Vertical Incidence Sky-wave (NVIS) propagation?Sky-wave (NVIS) propagation?

A.A. Propagation near the MUFPropagation near the MUFB.B. Short distance HF propagation using high elevation Short distance HF propagation using high elevation

anglesanglesC.C. Long path HF propagation at sunrise and sunsetLong path HF propagation at sunrise and sunsetD.D. Double hop propagation near the LUFDouble hop propagation near the LUF


G3C13 What is Near Vertical Incidence G3C13 What is Near Vertical Incidence Sky-wave (NVIS) propagation?Sky-wave (NVIS) propagation?

A.A. Propagation near the MUFPropagation near the MUFB.B. Short distance HF propagation using high Short distance HF propagation using high elevation angleselevation angles

C.C. Long path HF propagation at sunrise and sunsetLong path HF propagation at sunrise and sunsetD.D. Double hop propagation near the LUFDouble hop propagation near the LUF


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

A.A. A vertical antennaA vertical antennaB.B. A horizontal dipole placed between 1/8 and 1/4 A horizontal dipole placed between 1/8 and 1/4

wavelength above the groundwavelength above the groundC.C. A left-hand circularly polarized antennaA left-hand circularly polarized antennaD.D. A right-hand circularly polarized antennaA right-hand circularly polarized antenna


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

A.A. A vertical antennaA vertical antennaB.B. A horizontal dipole placed between 1/8 A horizontal dipole placed between 1/8 and 1/4 wavelength above the groundand 1/4 wavelength above the ground

C.C. A left-hand circularly polarized antennaA left-hand circularly polarized antennaD.D. A right-hand circularly polarized antennaA right-hand circularly polarized antenna


G3 - RADIO WAVE PROPAGATION G3 - RADIO WAVE PROPAGATION [3 Exam Questions - 3 Groups][3 Exam Questions - 3 Groups]

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G3 - RADIO WAVE PROPAGATION [3 Exam Questions - 3 Groups]