Feeders

• Electromagnetic waves in free space travel at the speed of light
• In transmission lines the speed of the wave is slowed down by a factor K called the velocity factor of the line
• A half wave in free space is:
  • 150÷ƒ , where ƒ is in MHz, result is in meters
  • (492÷ƒ result in feet)
• A half wave transmission line length in meters is the free space value × K, where K (the velocity factor) is always less than 1 and depends on the type of cable used

Course Guide Topics

1. Purpose
2. Types of feeder
3. Characteristic Impedance
4. Parallel Conductor Line
5. Preventing Line Radiation
6. Balanced Line
7. Coaxial Line (Coax) (1)
8. Coaxial Line (Coax) (2)
9. Waveguide
10. Velocity Factor
11. Velocity Factor (Contd)
12. Terminated Line
    (Matched Case) (1)
13. Terminated Line
    (Matched Case) (2)
14. Terminated Line
    (Unmatched Case)
15. Standing Waves (1)
16. Standing Waves (2)
17. Standing Waves (3)
18. Line Loss (1)
19. Line Loss (2)
20. Matching
21. Matching – Quarter Wave Transformer (1)
22. Matching – Quarter Wave Transformer (2)
23. Lines as Tuned Circuits
24. Open Circuit
25. Short Circuit
26. Stubs
27. Stub Characteristics
28. Antenna Tuning Units – ATU
29. Balance/Unbalance
30. Baluns
31. Typical Baluns
32. 1:1 Current Balun
33. 4:1 Voltage Balun
34. 1:1 Voltage Balun
35. 4:1 Transmission Line Voltage Balun