Transmission Lines for the Terrified

Jeff 9V1AS Filename:BB249_70

Hopefully, by the end of this talk, you will be able to answer the questions:1. "What is reflection coefficient?" 2. "What is VSWR" 3. "What is matching?" 4. "What are standing waves?" 5. "How much of my transmitted power is going out when my VSWR is 2?" 6. “What happens if the XYL keys up the 300W Linear while I am adjusting the spacers on the open wire feeder?”7. Why 50 ohms?8. Explain velocity factor

Jeff 9V1AS

Jeff 9V1AS

What is characteristic impedance?

Jeff 9V1AS

Yes, I can see your formulae, but I still can’t grasp the concept of characteristic impedance!

OK, let’s try again

Jeff 9V1AS

Characteristic Impedance Formulae for common transmission line types

Jeff 9V1AS

Why 50 ohms?

Jeff 9V1AS

Why 50 ohms?

Jeff 9V1AS

Why 50 ohms?

Jeff 9V1AS

Transmission and reflection

Jeff 9V1AS

Standing waves along a mismatched line (1)

Jeff 9V1AS

Standing waves along a mismatched line (2)

Jeff 9V1AS

What happens to the voltage and current for various terminations.

Jeff 9V1AS

V and I distribution for the special cases of ¼ and ½ lambda

Jeff 9V1AS

Lumped equivalents for TLs just less, equal, greater than ¼ lambda

Jeff 9V1AS

Different lengths can behave like different lumped circuits!

What’s the catch?.....

Jeff 9V1AS

Some special properties of ¼ and ½ lambda lines

Jeff 9V1AS

Jeff 9V1AS

"This is the last time you're coming home late from your ham radio club meeting"!

Jeff 9V1AS