What is a characteristic of skywave signals arriving at your location by both short-path and long-path propagation?

1. A Periodic fading approximately every 10 seconds
2. B Signal strength increased by 3 dB
3. C The signal might be cancelled causing severe attenuation
4. D A slightly delayed echo might be heard

What factors affect the MUF?

1. A Path distance and location
2. B Time of day and season
3. C Solar radiation and ionospheric disturbances
4. D All these choices are correct

Which frequency will have the least attenuation for long-distance skip propagation?

1. A Just below the MUF
2. B Just above the LUF
3. C Just below the critical frequency
4. D Just above the critical frequency

Which of the following is a way to determine current propagation on a desired band from your station?

1. A Use a network of automated receiving stations on the internet to see where your transmissions are being received
2. B Check the A-index
3. C Send a series of dots and listen for echoes
4. D All these choices are correct

How does the ionosphere affect radio waves with frequencies below the MUF and above the LUF?

1. A They are refracted back to Earth
2. B They pass through the ionosphere
3. C They are amplified by interaction with the ionosphere
4. D They are refracted and trapped in the ionosphere to circle Earth

What usually happens to radio waves with frequencies below the LUF?

1. A They are refracted back to Earth
2. B They pass through the ionosphere
3. C They are attenuated before reaching the destination
4. D They are refracted and trapped in the ionosphere to circle Earth

What does LUF stand for?

1. A The Lowest Usable Frequency for communications between two specific points
2. B The Lowest Usable Frequency for communications to any point outside a 100-mile radius
3. C The Lowest Usable Frequency during a 24-hour period
4. D The Lowest Usable Frequency during the past 60 minutes

What does MUF stand for?

1. A The Minimum Usable Frequency for communications between two points
2. B The Maximum Usable Frequency for communications between two points
3. C The Minimum Usable Frequency during a 24-hour period
4. D The Maximum Usable Frequency during a 24-hour period

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

1. A 180 miles
2. B 1,200 miles
3. C 2,500 miles
4. D 12,000 miles

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

1. A 180 miles
2. B 1,200 miles
3. C 2,500 miles
4. D 12,000 miles

What happens to HF propagation when the LUF exceeds the MUF?

1. A Propagation via ordinary skywave communications is not possible over that path
2. B HF communications over the path are enhanced
3. C Double-hop propagation along the path is more common
4. D Propagation over the path on all HF frequencies is enhanced

Which of the following is typical of the lower HF frequencies during the summer?

1. A Poor propagation at any time of day
2. B World-wide propagation during daylight hours
3. C Heavy distortion on signals due to photon absorption
4. D High levels of atmospheric noise or static