Signal Characteristics

Question 1

What is a Cycle?

Answer 1

One positive and one negative iteration of a wave, representing a full 360 degrees.

Question 2

What is a Period?

Answer 2

Time it takes to complete one cycle, measured in seconds.

Question 3

What is Frequency?

Answer 3

Number of cycles completed in one second, measured in Hertz

Question 4

What is Phase?

Answer 4

Denotes the particular point in the cycle of a waveform, measured as an angle in degrees

Question 5

What is wavelength?

Answer 5

The distance of one cycle, measured at the beginning and end of the waveform.

Question 6

What is amplitude?

Answer 6

Value of the power of a sine wave, measured in decibels.

Question 7

What is Signal Propagation?

Answer 7

How an EM wave travels through a medium from a transmitter to receiver.

Question 8

What are the three Signal Propagation Mechanisms?

Answer 8

1. Reflection - when a signal bounces off a surface in a different direction
2. Diffraction - occurs when the signal bends around an object
3. Scattering - occurs when the signal encounters small objects and gets scattered in multiple directions

Question 9

What is Free Space Loss?

Answer 9

Power loss due to spreading of the wave’s energy.

Question 10

List the four Natural Interference/Propagation Effects

Answer 10

1. Scintillation
2. Faraday Rotation
3. Water/Atmosphere Absorption
4. Free Space Loss

Question 11

What is Polarization?

Answer 11

Refers to the direction of an electromagnetic wave’s E-field in reference to the earth’s surface

Question 12

What are the two categories of Polarization?

Answer 12

1. Linear (Vertical and Horizontal)
2. Circular (Right Hand Circular and Left Hand Circular)

Question 13

What is an advantage and disadvantage of Linear Polarization

Answer 13

Advantage:
Ability to re-use same frequency and bandwidth on a transponder without interference

Disadvantage:
Precise orientation of polarizer with EM wave is required to receive full signal strength

Question 14

What is an advantage and disadvantage of Circular Polarization?

Answer 14

Advantage:
Not significantly impacted by Faraday Rotation

Disadvantage:
If utilizing an Orthomode Transducer to receive both RH and LH simultaneously, you will incur a -3dB loss

Question 15

Frequency Band and Range Chart

Answer 15

UHF: 300 MHz - 1 GHz

L: 1-2 GHz
S: 2-4 GHz
C: 4-8 GHz
X: 8-12 GHz
Ku: 12-18 GHz
K: 18-27 GHz
Ka: 27-40 GHz