Advanced Qualification · A-007 Feedlines and matching · A-007-001-009
What advantage does a pi-L network have over a pi-network for impedance matching between a vacuum tube linear amplifier and a multiband antenna?
- A Higher efficiency
- B Lower losses
- C Greater transformation range
- D Greater harmonic suppression
Correct answer: D — Greater harmonic suppression. From the official ISED question bank, verified word for word.
Why
A pi-L network adds an extra inductor and capacitor to the standard pi-network, creating a steeper filter that blocks unwanted harmonic frequencies more effectively before they reach the antenna. The full explanation — and one for every question — is in Pro.
Practise this section
Feedlines and matching at the advanced level: transmission line theory, impedance transformation, stubs and matching networks.