E3B-2012: Propagation and technique, trans-equatorial; long path; gray-line; multi-path propagation
What is transequatorial propagation?
Propagation between two mid-latitude points at approximately the same distance north and south of the magnetic equator
Propagation between any two points located on the magnetic equator
Propagation between two continents by way of ducts along the magnetic equator
Propagation between two stations at the same latitude
What is the approximate maximum range for signals using transequatorial propagation?
What is the best time of day for transequatorial propagation?
Afternoon or early evening
Late at night
What type of propagation is probably occurring if an HF beam antenna must be pointed in a direction 180 degrees away from a station to receive the strongest signals?
Which amateur bands typically support long-path propagation?
160 to 10 meters
160 to 40 meters
30 to 10 meters
6 meters to 2 meters
Which of the following amateur bands most frequently provides long-path propagation?
Which of the following could account for hearing an echo on the received signal of a distant station?
Receipt of a signal by more than one path
High D layer absorption
Transmit frequency is higher than the MUF
What type of HF propagation is probably occurring if radio signals travel along the terminator between daylight and darkness?
At what time of day is gray-line propagation most likely to occur?
At sunrise and sunset
When the Sun is directly above the location of the transmitting station
When the Sun is directly overhead at the middle of the communications path between the two stations
When the Sun is directly above the location of the receiving station
What is the cause of gray-line propagation?
At twilight, D-layer absorption drops while E-layer and F-layer propagation remain strong
At midday, the Sun being directly overhead superheats the ionosphere causing increased refraction of radio waves
In darkness, solar absorption drops greatly while atmospheric ionization remains steady
At mid afternoon, the Sun heats the ionosphere decreasing radio wave refraction and the MUF
Which of the following describes gray-line propagation?
Long distance communications at twilight on frequencies less than 15 MHz
Backscatter contacts on the 10 meter band
Over the horizon propagation on the 6 and 2 meter bands
Tropospheric propagation on the 2 meter and 70 centimeter bands
● = Unseen
● = Weak
● = Review
● = Learned
● = Incorrect answer