16 terms

G3 A Radio Propagation

Radio Propagation
STUDY
PLAY
G3A01 -What is the sunspot number? A. A measure of solar activity based on counting sunspots and sunspot groups B. A 3 digit identifier which is used to track individual sunspots C. A measure of the radio flux from the Sun measured at 10.7 cm D. A measure of the sunspot count based on radio flux measurements
(A)
G3A02 -What effect does a Sudden Ionospheric Disturbance have on the daytime ionospheric propagation of HF radio waves? A. It enhances propagation on all HF frequencies B. It disrupts signals on lower frequencies more than those on higher frequencies C. It disrupts communications via satellite more than direct communications D. None, because only areas on the night side of the Earth are affected
(B)
G3A03 -Approximately how long does it take the increased ultraviolet and X-ray radiation from solar flares to affect radio-wave propagation on the Earth? A. 28 days B. 1 to 2 hours C. 8 minutes D. 20 to 40 hours
(C)
G3A04 -Which of the following amateur radio HF frequencies are least reliable for long distance communications during periods of low solar activity? A. 3.5 MHz and lower B. 7 MHz C. 10 MHz D. 21 MHz and higher
(D)
G3A05 -What is the solar-flux index? A. A measure of the highest frequency that is useful for ionospheric propagation between two points on the Earth B. A count of sunspots which is adjusted for solar emissions C. Another name for the American sunspot number D. A measure of solar radiation at 10.7 cm
(D)
G3A06 -What is a geomagnetic storm? A. A sudden drop in the solar-flux index B. A thunderstorm which affects radio propagation C. Ripples in the ionosphere D. A temporary disturbance in the Earth's magnetosphere
(D)
G3A07 -At what point in the solar cycle does the 20 meter band usually support worldwide propagation during daylight hours? A. At the summer solstice B. Only at the maximum point of the solar cycle C. Only at the minimum point of the solar cycle D. At any point in the solar cycle
(D)
G3A08 -Which of the following effects can a geomagnetic storm have on radio-wave propagation? A. Improved high-latitude HF propagation B. Degraded high-latitude HF propagation C. Improved ground-wave propagation D. Improved chances of UHF ducting
(B)
G3A09 -What effect do high sunspot numbers have on radio communications? A. High-frequency radio signals become weak and distorted B. Frequencies above 300 MHz become usable for long-distance communication C. Long-distance communication in the upper HF and lower VHF range is enhanced D. Microwave communications become unstable
(C)
G3A10 -What causes HF propagation conditions to vary periodically in a 28-day cycle? A. Long term oscillations in the upper atmosphere B. Cyclic variation in the Earth's radiation belts C. The Sun's rotation on its axis D. The position of the Moon in its orbit
(C)
G3A11 -Approximately how long is the typical sunspot cycle? A. 8 minutes B. 40 hours C. 28 days D. 11 years
(D)
G3A12 -What does the K-index indicate? A. The relative position of sunspots on the surface of the Sun B. The short term stability of the Earth's magnetic field C. The stability of the Sun's magnetic field D. The solar radio flux at Boulder, Colorado
(B)
G3A13 -What does the A-index indicate? A. The relative position of sunspots on the surface of the Sun B. The amount of polarization of the Sun's electric field C. The long term stability of the Earth's geomagnetic field D. The solar radio flux at Boulder, Colorado
(C)
G3A14 -How are radio communications usually affected by the charged particles that reach the Earth from solar coronal holes? A. HF communications are improved B. HF communications are disturbed C. VHF/UHF ducting is improved D. VHF/UHF ducting is disturbed
(B)
G3A15 -How long does it take charged particles from coronal mass ejections to affect radio-wave propagation on the Earth? A. 28 days B. 14 days C. 4 to 8 minutes D. 20 to 40 hours
(D)
G3A16 -What is a possible benefit to radio communications resulting from periods of high geomagnetic activity? A. Aurora that can reflect VHF signals B. Higher signal strength for HF signals passing through the polar regions C. Improved HF long path propagation D. Reduced long delayed echoes
(A)
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