Advanced Qualification · A-007 Feedlines and matching · A-007-005-010
En service radioamateur, quelle erreur d'uniformité de surface devriez-vous tenter de ne pas excéder pour un réflecteur parabolique?
- A0,1 lambda
- B0,25 lambda
- C5 mm (0.2 po), peu importe la fréquence
- D1% du diamètre
Correct answer: A — 0,1 lambda. Question tirée de la banque officielle d'ISDE.
Why
A surface error limit of 0.1 lambda ensures the reflected radio waves stay in step, or in phase, so they combine to form a strong signal rather than cancelling each other out. 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.
Drill A-007 — free, no account