CRAC Class B (2025) — Questions 571–580

RIT = Receive Incremental Tuning. It shifts only the receive frequency by a small amount (typically ±9.9 kHz) without moving the transmit (main) frequency, useful when the other station's signal is slightly off (A). XIT (B) is the transmit counterpart; SPLIT (C) is independent Tx/Rx; clearing memory (D) is unrelated.

XIT = Transmit Incremental Tuning. It offsets only the transmit frequency slightly while the main (receive) tuning stays put (A). It is the transmit counterpart of RIT (B); SPLIT (C) and memory clear (D) are different functions.

SPLIT means operating with receive and transmit on different frequencies (A). It is distinct from XIT/RIT (small offsets of one side) and from memory clear (D). Often the transmit VFO is offset to a separate frequency while receiving on another.

Split is primarily used to manage a pile-up: the DX station transmits on one frequency and asks callers to transmit a few kHz away so it can hear them amid the crowd (A). It is also used when correspondents are in different regions/bands and must operate on different frequencies to complete the contact (B). C (hiding conversation) is not a legitimate purpose, and D (can't make gear co-frequency) is a misuse rather than the intended scenario.

An SSB/CW signal that sounds off-pitch is slightly off your receive tuning; RIT lets you retune the receive frequency a few kHz without moving your transmit frequency, restoring normal pitch (A). Bandwidth (B) affects selectivity, squelch (C) gates the audio, and AGC speed (D) affects audio dynamics — none fix pitch.

CW-R (CW reverse) flips which sideband the receiver demodulates. Since CW is often received with a sideband plus BFO, reversing can move an adjacent interfering signal out of your passband, reducing/eliminating interference (A). It does not generate a cancelling sideband (B), double capacity (C), or prevent keying (D).

QSK / full break-in means the transceiver switches to receive between individual CW elements (dots/dashes), so you can hear the other station — or your own keying — in the infinitesimally short gaps (A). It does not require manual switching (B), speed up the keyer (C), or raise power (D).

Selectable IF bandwidth lets you match the filter to the mode (narrow for CW, wide for AM), rejecting out-of-band noise and adjacent stations to improve SNR (A). The other options describe multi-receiver architectures, not the benefit of bandwidth choice itself.

Matching bandwidth to mode: CW is narrow (100 Hz or 400 Hz) (A); SSB needs ~2.7 kHz (B); AM is widest among these voice modes at ~6 kHz (C). FT8, however, has a very small necessary bandwidth (~50 Hz) and is best received with the narrowest filter (100 Hz), not 400 Hz, so D is incorrect. The official key marks A, B, C.

Matching the receive bandwidth to the mode's necessary bandwidth excludes the maximum amount of out-of-band noise and interference, giving the optimal SNR (A). Input impedance (B), dynamic range (C), and band visibility (D) are not the reasons for bandwidth matching.