Week 2

Question 1

What is RF

Answer 1

Radio Frequency

Question 2

What is the characteristics of Electromagnetic/RF signals?

Answer 2

Amplitude, Wavelength (lambda(cm)), Frequency(Hz(number of oscilaltion per seconds)

Question 3

How to calculate frequency(Hz)

Answer 3

f(Hz)=c (300,000km/s)/lambda (cm)

Question 4

Type of Radio Frequency interference

Answer 4

Refraction, Diffraction, Scattering, Absorbtion, Amplification, Attenuation

Question 4

Formula to calculate power at distance

Answer 4

p= P/4pir^2 Watts/m2

Question 5

Formula to calculate power received from a satellite dish

Answer 5

A of efficiency= 4pi d^2 n(efficiency of plate)

Question 6

What power will receive based on:
Output power is 100mW
The receiver is 100m from the transmitter (isotropic)
The receiver is 0.25m radius (with efficiency 55%)

Answer 6

Use power at distance formula, coupled with parabolic dish efficiency calculator.
0.1/4pi(100)^2 * 4pi(0.5)^2*0.55 =Watts/m2

Question 7

What is Voltage Standing Wave Ratio

Answer 7

How efficient RF signal transmitted from source to load

When impedence exists.
It is a wave caused by impedance mismatch between connectors, causing opposite flow of currect in a alternative current circuit

Question 8

How do we calculate Voltage Standing Wave Ratio (Return loss)

Answer 8

Find power= (current-resistance/current+resistance)

Then
VSWR=(1+POWER/1-POWER)

Question 9

What is decibals(dB)

Answer 9

Decibals is known as the unit of change, to calculate the differences between two signals

Question 10

How to calculate decibals

Answer 10

log(power in mW/1mW)*10=dBm

Question 11

What is RSSI

Answer 11

RECEIVED SIGNAL STRENGTH INDICATOR is a relative value of the strength and quality of an RF signal being received by the antenna

Question 12

What affects network connectivity

Answer 12

path loss, noise, shadowing, multipath, frequency dispersion

Question 13

What is EIRP

Answer 13

Effective Isotropic Radiated power

Question 14

What does EIRP DO

Answer 14

Amount of power emitted from a isotropic antenna to produce peak power density observed in direction of maximum antenna gain

Question 15

Q1: calculate the EIRP value.
Assuming output of transmitter is 100mW
Cable loss is 3dB
Antenna is 6dBi

Answer 15

convert the transmitter to decibals,
log(100)*10= 20dB
Then, 20dB-3dB+6dB

Question 16

Calculate both watts value and decibals value:
Assuming Transmitter is 100mW
cable loss is 3dB
Antenna is 10dBi

Answer 16

Value for dB is 27dBm
value for watts is 500 mW