NAVEDTRA 14189A, Ch. 5 Flashcards
The frequency range from ELF to SHF is from below 300 hertz up to how many gigahertz?
30
What is a non-radiating device called that absorbs the rf and has the impedance characteristics of the antenna?
Dummy load
What is a small building called that is physically separated from the transmitter location that contains antenna loading, coupling, and tuning circuits?
Helix House
Which type of antenna is a special form of a rhombic-arranged monopole array that is designed to transmit from a particular location?
Triatic
Communications systems in which portion of the radio frequency spectrum use line-of-sight propagation?
1 to 10 gigahertz
The distance between microwave system hop points ranges from 50 to 150 kilometers (31 to how many statute miles)?
95
The tropo system uses the turbulence in the layer between the troposphere and the stratosphere to bounce signals back to earth and has a transmission range up to 800 kilometers (how many statute miles)?
500
HF has a hop distance (skywave) of about how many miles?
1,400
The distance of one hop for a line-of-sight system is between 31 and how many miles?
95
What was developed by the U.S. Navy as a command tool for commanders in tactical combat situations?
NTDS
How many separate data transmission links does NTDS use to maintain tactical data communications between tactical units?
Three
What provides high-speed, computer-to-computer transfer of tactical information, command orders, and unit status to all tactical data systems?
Link 11
What provides a means of transmitting track information to those units not capable of participating in the link 11 network?
Link 14
What permits the computer to take control of the autopilot in an equipped aircraft?
Link 4a
What is the international distress frequency?
500 kilohertz
What is the survival craft communications frequency?
8,364 kilohertz
What take energy at (or near) the visible light spectrum and convert it to a very narrow and intense beam in the same region?
Lasers
Which color of communications lasers could possibly penetrate the ocean to great depths?
Blue-green
What is a type of two-equipment installation where one unit can be substituted for another in the event of failure?
Doubling up
What acts as a coil and is used with variable inductors for impedance matching of high-power transmitters?
Helix
What are conductors or optical waveguides called that readily pass light?
Fiber optics
