CRAC Class C (2025) — Questions 21–30
U0020. The international organization that coordinates international radio management is:
协调国际无线电管理的国际组织是：
Exam tips · 考试提示
The international organization coordinating radio management is the 国际电信联盟 (International Telecommunication Union, ITU). IARU is the amateur union, not the regulator; the UN General Assembly and UNESCO are not the radio-coordination body.
U0021. The International Amateur Radio Union (IARU) supports its member societies in viewing the development of amateur radio as a:
国际业余无线电联盟支持会员协会在发展业余无线电时把它看 成一种：
Exam tips · 考试提示
The IARU supports member societies in viewing amateur radio development as a 国家资源 (national resource). The other options (economic stimulus, leisure, defense reserve) are not the IARU's stated framing.
U0022. Which of the following communications does NOT fall within the scope of telecommunication?
下述通信不属于电信（telecommunication）范畴：
Exam tips · 考试提示
电信 (telecommunication) is the transmission of signs, signals, text, images, sounds, etc., by wire, radio, optical, or other electromagnetic means. 邮政通信 (postal communication) is physical mail, not telecommunication.
U0023. Which of the following statements about radio communication is correct?
关于无线电通信的正确说法：
Exam tips · 考试提示
无线电通信 (radio communication) is the transmission, emission, or reception of symbols, signals, text, images, sounds, or other information by radio waves (A). B over-broadens to all EM including light; C wrongly excludes other information types; D misclassifies heating as communication.
U0024. Which of the following statements about terrestrial radio communication is correct?
关于地面无线电通信（terrestrial radio communication）的 正确说法是：
Exam tips · 考试提示
地面无线电通信 (terrestrial radio communication) includes communication between stations on or near the Earth's surface — aeronautical communication is terrestrial (A). Maritime is also terrestrial (B wrong); not all amateur contacts are terrestrial (satellite ones are not, C wrong); skywave/ionospheric communication is still terrestrial (D wrong).
U0025. Radio waves are:
无线电波是指：
Exam tips · 考试提示
无线电波 (radio waves) are electromagnetic waves propagating in space at frequencies below 3,000 GHz (A). B wrongly includes all EM below 3,000 GHz regardless of propagation; C/D use wrong frequency ranges. 业余无线电台的设置与审批 Amateur Station Establishment and Approval
U0040. Where an amateur radio station license needs to continue to be used after its validity period expires, an application to renew the license should be submitted to the radio management authority that made the licensing decision within which of the following periods?
业余无线电台执照有效期届满后需要继续使用的，应当在下列 期限内向作出许可决定的无线电管理机构申请更换业余无线电 台执照：
Exam tips · 考试提示
License renewal must be applied for 30 working days before expiry (期限届满30个工作日前) to the original licensing authority. The other periods (half-year/two/three months after) are wrong.
U0041. Where the particulars recorded in an amateur radio station license are to be changed, which procedure should be followed?
变更业余无线电台执照载明事项的，应当办理下列手续：
Exam tips · 考试提示
Changing recorded particulars requires promptly applying to the original licensing authority for a change (A). You may not wait until expiry (B), skip it if model/serial unchanged (C), or merely file a record (D).
U0042. When ceasing to use an amateur radio station, the license cancellation procedure should be handled with which of the following authorities?
终止使用业余无线电台的，应向下列哪个机构办理业余无线电 台执照注销手续：
Exam tips · 考试提示
When ceasing station use, cancellation is handled by the authority that made the licensing decision (作出许可决定的无线电管理机构) (A). The national authority, CRAC, or entrusted units are not the correct default.
U0043. Which of the following statements about ceasing to use an amateur radio station is correct? (Choose all that apply.)
关于终止使用业余无线电台的，下列说法正确的是：
Exam tips · 考试提示
On cessation you must promptly cancel (A) and return the license, then dismantle and properly dispose of the station/antenna within 60 working days of cancellation (B). C (6 months) and D (just return) are wrong.