Calculating Signal Loss

Question 1

Signal Loss

Answer 1

• Usually gradual
  
  • Signal strength diminish over distance
• Attenuation
  
  • Loss of intensity as signal moves through a medium

-Electrical signals through copper ; light through fiber

Question 2

Decibels

DB

Answer 2

• Signal strength ratio measurements
  
  • One-tenth of a bel
  • Capital B for Alexander Grand Bell
• Logarithmic Scale (Add & Subtract losses & Gains)
  
  • 3dB = 2x the signal
  • 10dB = 10x the signal
  • 20dB = 100x the signal
  • 30dB = 1000x the signal

Question 3

Calculating dB loss

Answer 3

• Additional & Subtractio
  
  • Easy to calculate

-Signal loss calculation
Total loss through 1km of fiber

• Add the loss through each section
  
  • 1km fiber = 3.5dB
  • Patch panel at each end = .5dB
  • (x2 patch panels) = 1dB Total loss = 4.5dB

Question 4

dB loss Symptoms

Answer 4

• No connectivity (No signal)
• Intermittent connectivity
• Poor performance
  
  • Signal too weak
  • CRC errors . data corruption

-Test each connection