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76 Cards in this Set

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What is propogation?
Movement through a medium
Define Wave
A disturbance that moves through a medium
Define wave motion.
1.A reoccuring disturbance advancing through space. 2. Energy moving/transferring from one point to another.
What are traverse waves?
Traverse waves travel at right angles to te direction of propogation. (light, heat , radio)
What are longitudinal waves?
Longitudinal waves are waves in which the disturbance takes place in the direction of propagation.
List Formulas: velocity, frequency,time, wavelength
V = f x wavelength
T (1 vibration)=1/f
f = 1/ T
Wavelength= v/f
What is the law of reflection?
The angle of incidence is equal to the angle of reflection.
List frequency ranges for light spectrum. red, orange, yellow, green, blue green, blue, indigo, violet
Red = 650-800
Orange = 600- 650
Yellow = 580-600
green = 520- 580
Green blue = 500-520
Blue = 470-500
Indigo = 440-470
violet = 400-440
State the frequency range for VLF waves.
3Hz - 30 Hz
State the frequency range for LF waves.
30Hz - 300Hz
State the frequency range for MF waves.
300 Hz - 3 MHz
State the frequency range for HF waves.
3 MHz - 30 MHz
State the frequency range for VHF waves.
30 MHz - 300 MHz
State the frequency range for UHF waves.
300 MHz - 3 GHz
State the frequency range for SHF waves
3 GHz- 30 GHz
State the frequency range for EHF.
30 GHz- 300 GHz
What is the major advantage of the telegraph over earlier mentods of communiction?
Range
Radio waves trave at what speed?
Speed of light
Which type of energy cannot be seen, heard, or felt?
Radio waves
What is the wave law of reflection?
The angle of incidence is equal to the angle of reflection.
What is the vehicle through which a wave travels from point to point?
Medium
The reception of an AM-band radio signal over mountains can be explained by which of the following principles of wave propagation?
Diffraction
What wave propagatiion principle accounts for the alleged increase in frequency ans a train whistle approaches and the alleged decrease in frequency as it moves away?
Doppler Effect
Longitudinal wave disturbances that travel through a medium are known as what type of waves?
Sound
Varying which of the following wavve characteristics will cause the length of sound waves to vary?
Frequency
What are the 3 basic characteristics of sound?
Pitch intensity and quality
In sound terms, what is the same as a wave reflection?
Echo
Multiple reflections of sound waves are
Reverberation
A cavity that vibrates at its own natural frequency and makes a sound louder than other frequencies demonstrates what sound wave term?
Resonance
The scientist, J.C. Maxwell, developed the theory that small packets of electromagnetic energy called photons produce:
Light
Define light beam
A large volume of light radiating in a fiven direction
What are the primary colors of light
RGB redgreen blue
What are the secondary colors of light
Magenta yellow and cyan
What causes sunlight to separate ino different wavelengths and display a rainbow of colors when passed thru a prism?
Dispersion
The sun, gas flames, and electric light filaments are visible because they are
Self luminous
Define translucence
Substance are able to transmit light waves but objects cannot be seen through them.
Define transparence
Substances that transmit almost all of the light waves falling upon them
the electromagnetic range arranges waves in order of its
frequency
what type of wave has the highest frequency?
X Ray
What device is used to radiate and or collect electromagnetic waves
Antenna
The electromagnetic field is comprised of
Electric field and magnetic field
The magnetic field radiated from an antenna is produced by what
Electrical Current
The Electric field radiated from an antenna is produced by what property?
Electrical voltage
Applying rf energy to the elements of an antenna results in what relationship between voltage and current?
Rhase relationship where voltage lags current by 90 degres
What field exists close to the conductor of an antenna?
THE iNDUCTION FIELD it also carries a current
What field travels through space after being detached from the current-carrying rod of an antenna?
Radiation
When do electric and magnetic fields on an antenna reach their maximum intensity?
When they are a quarter-cycle apart
When do electric and magnetic fields on an antenna reach their maximum intensity?
When they are a quarter-cycle apart
What is input impedence?
A measure of the voltage to current ration (Ein/I in) at the input end of a transmission line
What is input impedence?
A measure of the voltage to current ration (Ein/I in) at the input end of a transmission line
Name an advantage of a shielded pair transmission line
Uniform capacitance (no loss) throughout the line
Name an advantage of a shielded pair transmission line
Uniform capacitance (no loss) throughout the line
What is the #1 advanage of coaxial cable lines?
Low radiation losses
What is the #1 advanage of coaxial cable lines?
Low radiation losses
Define radiatiON
When transmission line loss is caused by magnetic line of force not returning to the conductor
Define radiatiON
When transmission line loss is caused by magnetic line of force not returning to the conductor
What is the standard characteristic impedance of a transmission line
50-600 ohms
What is the standard characteristic impedance of a transmission line
50-600 ohms
Define incident waves
The initial waves that travel from the source to the load of a transmission line
Define incident waves
The initial waves that travel from the source to the load of a transmission line
Define reflected waves
Waves that travel from the output end to the input end of a transmission line
Define reflected waves
Waves that travel from the output end to the input end of a transmission line
What characteristics control the velocity of propagation?
Capacitance and inductance
What characteristics control the velocity of propagation?
Capacitance and inductance
Current X voltage =
he total charge on a transmission line
Current X voltage =
he total charge on a transmission line
What is the total # of moving waves in an AC signal
2
What is the general maximum distance for Line Of Sight Communications?
25 miles
Transmission of informatiion to a satellite is don on what frequency?
UP-Link
An earth terminal receives signals on what frequency?
DOwnlink
Define perigree
THe part of a satellite's orbit closest to the earth
In a LOS communication system, propagatiion is affected bywhich of the following layers of the atmosphere?
Troposphere upto 16 Km
Radio waves refract off of what atmosheric layer?
Ionosphere
Airplanes fly in this layer of the atmoshpere.
Stratosphere also contains our O zone layer Upto 50 Km
Discuss the mesosphere.
Too high for aircraft 80 Km, too low for satellites, meteors burn up here
Dicscuss thermosphere
500-1,000 Km above the earth, contains ionosphere where satellites orbit, solar flares and gravity affects the radio wave because many wave atoms have lost electrons causing them to be charged ions influenced by these things