CRAC Class A (2025) — Questions 251–260
U0250. Regulations and international amateur radio practice require the following as the necessary contents of an amateur station log:
法规和国际业余无线电惯例要求业余电台日志应记载的必要内 容是：
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The required log (电台日志) essentials are: date/time, frequency, mode, the correspondent's call sign, and signal reports (RST/RS). Option A matches. Names, equipment, QTH, and weather are not mandatory log fields.
U0251. Exchanging QSL cards between amateur radio stations has multiple meanings, including: (Choose all that apply.)
业余无线电台交换QSL卡具有多重意义，包括：
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QSL cards serve many purposes: confirming contacts (本地/国 内/全球) (A), recording station/equipment performance including homebrew (B), supporting award (奖状) applications (C), and the hobby of collecting/displaying cards (D). All four are valid meanings of QSL exchange.
U0252. What contents should a QSL card at least cover? (Choose all that apply.)
QSL卡片应至少涵盖哪些内容：
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A valid QSL card must carry: both call signs (A), signal reports and time (B), mode and frequency (C), and the operator's signature/stamp plus the station's return address (D). All four are minimum required contents so the card can serve as proof of contact.
U0253. Regarding the use of QSL cards, which of the following statements is correct?
关于QSL卡片的用法，以下说法正确的是：
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A QSL used for a non-contact purpose (e.g., a face-to-face "Eyeball QSO") must state that in the mode field, and blank cards should not be handed out. Option A is correct. B (giving blank cards as photos/name cards) and D (filling a wrong/absent call with a name) defeat the card's purpose; C (confirming a contact that never happened) is fraudulent.
U0254. When you receive a QSL card mailed from overseas and the envelope also contains one or more IRCs (International Reply Coupons), you should:
收到国外寄来的QSL卡片时，如果信封中夹带有一张或多张 IRC，则应：
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An overseas QSL with IRCs (国际回信券) is a direct request for a return card. The correct step is to verify the contact in your log, then return your QSL directly to the sender's address (using the IRC for postage). Option A is correct; B skips verification, C routes via the bureau (not "direct" as requested by IRCs), and D is dismissive and wrong.
U0255. The correct way to fill in and mail a QSL card is:
填写和邮寄QSL卡片的正确做法是：
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For a prompt direct return, mail your card to the other station's address with a SASE (self-addressed stamped envelope) enclosed. Option A is correct. B (correction fluid/overwriting) makes a card look altered; C confuses QTH (operating location) with mailing address (should go in the address area, not QTH); D is contradictory — "via bureau" vs "QSL DIRECT".
U0256. When exchanging QSL cards, we sometimes meet a special kind of radio enthusiast who only sends us a listening (SWL) card. After confirming the card's contents we promptly return a card out of respect. This kind of enthusiast is:
交换QSL卡片时，我们时有遇见一类特殊的无线电爱好者，他 们仅向我们寄发收听卡片。而我们在确认卡片所载内容之后会 立即回卡以示敬意。这类爱好者是：
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A shortwave listener (短波收听者, SWL) is not a licensed transmitting operator but sends "listener" QSLs confirming they heard your station. Option A is correct. Broadcast enthusiasts listen to broadcasts (not typically sending amateur QSLs), and DIY/monitor labels do not fit.
U0257. When working through a repeater, we should preset the radio's receive/transmit offset in advance, so we can smoothly handle operations on the uplink or downlink frequencies and avoid setting things up mid-contact and making mistakes. The uplink/downlink frequency offsets of amateur repeaters in the 144 MHz and 430 MHz bands are, respectively:
通过中继台进行通联时，我们应事先设好电台的接收和发射频 差，以便顺利应对上行或下行频率上的各种操作，避免边联络 边设置，忙中出错。144和430MHz频段业余中继台的上下行 频差分别为：
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In China, 2 m (144 MHz) repeaters use a 0.6 MHz offset (typically −0.6 MHz) and 70 cm (430 MHz) repeaters use a 5 MHz offset (typically +5 MHz). Option A gives the correct pair. B lists channel step sizes, not offsets; C/D are wrong offsets.
U0258. If you call a specific amateur station through a repeater, you should:
如果通过中继台呼叫一部业余电台，你应当：
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A directed call through a repeater uses the same format as any directed call: name the station you're calling, then your own call. Option A is correct. B (break, break) and C (a CQ) are not directed calls; D is passive and unnecessary.
U0259. The principle for using an amateur repeater is:
业余中继台的使用原则是：
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Repeaters must stay available for emergencies, so their uplink/downlink should be idle except for brief necessary contacts (A). B (keep busy) defeats that purpose; C/D (association notices, student study chat) are not the stated priority principle and can congest the machine. 呼叫程序与守听 Calling Procedure and Listening