Advanced Qualification · A-007 Feedlines and matching · A-007-003-005
The driven element of a Yagi antenna is connected to a coaxial transmission line. The coax braid is connected to the centre of the driven element and the centre conductor is connected to a variable capacitor in series with an adjustable mechanical arrangement on one side of the driven element. The type of matching is:
- AT match
- Bzeta match
- Cgamma match
- Dlambda match
Correct answer: C — gamma match. From the official ISED question bank, verified word for word.
Why
This setup describes a gamma match because it uses a single wire running parallel to one side of the driven element, connected to the coax centre conductor through a series capacitor, while the coax braid connects directly to the element centre. The full explanation — and one for every question — is in Pro.
Practise this section
Feedlines and matching is section A-007 of the Advanced exam: Feedlines and matching at the advanced level: transmission line theory, impedance transformation, stubs and matching networks.
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