Basic Qualification · B-005 Basic electronics and theory · B-005-008-011
Un radioamateur local rapporte que votre émission 2 mètres en simplex, à 100 W, lui donne une lecture de 30 dB au-dessus de S9. Pour réduire votre signal à S9, quelle puissance devez-vous utiliser?
- A33,3 W
- B0,1 W
- C1 W
- D10 W
Correct answer: B — 0,1 W. Question tirée de la banque officielle d'ISDE.
Why
To drop a signal from 30 dB over S9 down to just S9, you must reduce the power by exactly 30 decibels. The full explanation — and one for every question — is in Pro.
Practise this section
Basic electronics and theory is section B-005 of the Basic exam: The theory: Ohm's law, power, series and parallel circuits, AC and DC, frequency and wavelength, decibels, and the metric prefixes the exam leans on.
Drill B-005 — free, no account