3.5 KiB
3.5 KiB
G3B – Maximum Usable Frequency; Lowest Usable Frequency; short path and long path propagation; determining propagation conditions; ionospheric refraction
- G3B01 (D)
What is a characteristic of skywave signals arriving at your location by both short-path and long-path propagation? #card
- A. Periodic fading approximately every 10 seconds
- B. Signal strength increased by 3 dB
- C. The signal might be cancelled causing severe attenuation
- D. A slightly delayed echo might be heard
- G3B02 (D)
What factors affect the MUF? #card
- A. Path distance and location
- B. Time of day and season
- C. Solar radiation and ionospheric disturbances
- D. All these choices are correct
- G3B03 (A)
Which frequency will have the least attenuation for long-distance skip propagation? #card
- A. Just below the MUF
- B. Just above the LUF
- C. Just below the critical frequency
- D. Just above the critical frequency
- G3B04 (A)
Which of the following is a way to determine current propagation on a desired band from your station? #card
- A. Use a network of automated receiving stations on the internet to see where your transmissions are being received
- B. Check the A-index
- C. Send a series of dots and listen for echoes
- D. All these choices are correct
- G3B05 (A)
How does the ionosphere affect radio waves with frequencies below the MUF and above the LUF? #card
- A. They are refracted back to Earth
- B. They pass through the ionosphere
- C. They are amplified by interaction with the ionosphere
- D. They are refracted and trapped in the ionosphere to circle Earth
- G3B06 (C)
What usually happens to radio waves with frequencies below the LUF? #card
- A. They are refracted back to Earth
- B. They pass through the ionosphere
- C. They are attenuated before reaching the destination
- D. They are refracted and trapped in the ionosphere to circle Earth
- G3B07 (A)
What does LUF stand for? #card
- A. The Lowest Usable Frequency for communications between two specific points
- B. Lowest Usable Frequency for communications to any point outside a 100-mile radius
- C. The Lowest Usable Frequency during a 24-hour period
- D. Lowest Usable Frequency during the past 60 minutes
- G3B08 (B)
What does MUF stand for? #card
- A. The Minimum Usable Frequency for communications between two points
- B. The Maximum Usable Frequency for communications between two points
- C. The Minimum Usable Frequency during a 24-hour period
- D. The Maximum Usable Frequency during a 24-hour period
- G3B09 (C)
What is the approximate maximum distance along the Earth’s surface normally covered in one hop using the F2 region? #card
- A. 180 miles
- B. 1,200 miles
- C. 2,500 miles
- D. 12,000 miles
- G3B10 (B)
What is the approximate maximum distance along the Earth’s surface normally covered in one hop using the E region? #card
- A. 180 miles
- B. 1,200 miles
- C. 2,500 miles
- D. 12,000 miles
- G3B11 (A)
What happens to HF propagation when the LUF exceeds the MUF? #card
- A. Propagation via ordinary skywave communications is not possible over that path
- B. HF communications over the path are enhanced
- C. Double-hop propagation along the path is more common
- D. Propagation over the path on all HF frequencies is enhanced
- G3B12 (D)
Which of the following is typical of the lower HF frequencies during the summer? #card
- A. Poor propagation at any time of day
- B. World-wide propagation during daylight hours
- C. Heavy distortion on signals due to photon absorption
- D. High levels of atmospheric noise or static