General exam question G4A12
Subelement G4, AMATEUR RADIO PRACTICES· Group G4A
Which of the following is a common use of the dual-VFO feature on a transceiver?
- A.To allow transmitting on two frequencies at once
- B.To permit full duplex operation -- that is, transmitting and receiving at the same time
- C.To transmit on one frequency and listen on another (correct answer)
- D.To improve frequency accuracy by allowing variable frequency output (VFO) operation
WhyA common use of a transceiver's dual-VFO feature is to transmit on one frequency while listening on another. A dual-VFO transceiver lets the operator park one VFO on a transmit frequency and the other on a different receive frequency, which is exactly what's needed for split operation, transmitting on one frequency while listening on another, answer C. It doesn't enable transmitting on two frequencies simultaneously, doesn't provide full duplex, and "VFO" already means variable frequency oscillator, so D's claim about improving frequency accuracy doesn't describe what having two of them is for.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2023-2027 NCVEC Element 3 pool (public domain); the explanation above is original writing, see our methodology.
Related questions
- G4A01What is the purpose of the notch filter found on many HF transceivers?
- G4A02What is the benefit of using the opposite or “reverse” sideband when receiving CW?
- G4A03How does a noise blanker work?
- G4A04What is the effect on plate current of the correct setting of a vacuum-tube RF power amplifier’s TUNE control?
- G4A05Why is automatic level control (ALC) used with an RF power amplifier?