CRAC Bilingual Exam Manual (Class A / B / C) | 中国业余无线电台操作技术能力验证英中对照手册
The complete CRAC Class C question bank — 1229 questions in exam reading order. Click any question to jump to its bilingual Q&A card.
Radio Management Laws and Regulations无线电管理法规与规章 · 26 questions
- The administrative regulation specifically addressing radio management in our country, and its enacting author…
- The document specifically governing amateur radio stations in our country, and its enacting authority, are, re…
- The authority legally responsible for the supervision and administration of amateur radio stations in our coun…
- The regulatory document that specifically defines the radio-management terms "amateur service", "amateur-satel…
- When did the latest Measures for the Administration of Amateur Radio Stations (《业余无线电台管理办法》) come into force?
- The process of entering a specific frequency band into the Table of Frequency Allocations, stipulating that th…
- The process of specifying that a radio frequency or channel is to be used, within a designated area and under …
- The process of authorizing a radio station to use a radio frequency or channel under specified conditions is c…
- In the Table of Frequency Allocations, when a band is marked as allocated to multiple services, those services…
- Radiation means energy flow from any source emitted outward in the form of radio waves. Which of the following…
- Emission means: radiation or radiation products produced by a radio transmitting station. Which of the followi…
- Which of the following statements about general radio terminology is correct? (Choose all that apply.)
- Which of the following statements about an amateur radio station is correct?
- Which of the following statements about the amateur service and the amateur-satellite service is correct? (Cho…
- Which of the following statements about the definition of an amateur radio operator is correct? (Choose all th…
- Which of the following statements about emission class is correct? (Choose all that apply.)
- Which of the following statements about single-sideband (SSB) emission is correct?
- Which of the following statements about the definition of interference is correct? (Choose all that apply.)
- Which of the following statements about the definition of harmful interference is correct? (Choose all that ap…
- Which of the following statements about secondary-service stations is correct? (Choose all that apply.)
- The international organization that coordinates international radio management is:
- The International Amateur Radio Union (IARU) supports its member societies in viewing the development of amate…
- Which of the following communications does NOT fall within the scope of telecommunication?
- Which of the following statements about radio communication is correct?
- Which of the following statements about terrestrial radio communication is correct?
- Radio waves are:
Amateur Station Establishment and Approval业余无线电台的设置与审批 · 11 questions
- Where an amateur radio station license needs to continue to be used after its validity period expires, an appl…
- Where the particulars recorded in an amateur radio station license are to be changed, which procedure should b…
- When ceasing to use an amateur radio station, the license cancellation procedure should be handled with which …
- Which of the following statements about ceasing to use an amateur radio station is correct? (Choose all that a…
- Which of the following statements about amateur repeaters is INCORRECT? (Choose all that apply.)
- Which of the following statements about amateur beacon stations is INCORRECT? (Choose all that apply.)
- Which of the following statements about amateur repeaters are correct? (Choose all that apply.)
- Which of the following statements about establishing an amateur repeater is correct? (Choose all that apply.)
- The establishment and technical parameters of an amateur repeater should satisfy the following key conditions:
- Which of the following amateur radio stations are licensed by the national radio management authority? (Choose…
- Which of the following applications to establish and operate an amateur radio station should be submitted to t…
Operator Capability Verification操作技术能力验证 · 16 questions
- The national radio management authority and its entrusted organizations may organize and implement the followi…
- Into which classes is amateur radio operator-capability divided?
- The main difference between amateur radio stations of different classes lies in: (Choose all that apply.)
- The permitted operating frequency range and maximum transmit power for a Class A amateur radio station are:
- For a person who has obtained the Class B amateur radio operator certificate, the operating frequency bands an…
- For a person who has obtained the Class C amateur radio operator certificate, the operating frequency bands an…
- Which of the following requirements must be met to participate in the Class A amateur radio operator-capabilit…
- Which of the following requirements must be met to participate in the Class B amateur radio operator-capabilit…
- Which of the following requirements must be met to participate in the Class C amateur radio operator-capabilit…
- A person who has obtained the Class A amateur radio operator certificate may apply to establish and operate th…
- A person who has obtained the Class B amateur radio operator certificate may apply to establish and operate th…
- A person who has obtained the Class C amateur radio operator certificate may apply to establish and operate th…
- Which of the following statements about conducting special technical tests, QSOs, and similar activities is co…
- Which of the following is correct regarding minors establishing and operating amateur radio stations? (Choose …
- Which of the following statements about amateur radio operator-capability verification is correct? (Choose all…
- Regarding persons who lawfully obtained a Class B amateur radio operator-capability verification certificate b…
Amateur Station Call Signs业余无线电台呼号 · 4 questions
- Among the following call-sign prefixes, which one belongs to the same CQ zone as Egypt?
- The prefixes 3V, 4X, 5A and 6Y respectively represent the countries:
- The call sign of China's NCDXF/IARU beacon station is:
- Which of the following call-sign prefixes do NOT belong to space amateur radio stations? (Choose all that appl…
Lawful Establishment and Operation业余无线电台的法定设置与使用 · 36 questions
- The necessary step for lawfully establishing and operating an amateur radio station is:
- The statutory purpose of an amateur radio station is:
- When applying to establish and operate an amateur radio station equipped with multiple transmitting devices, y…
- The essential technical measure for an amateur repeater is:
- A group has lawfully established an amateur repeater. The correct practice is:
- The principle for choosing the same-band transmit/receive offset of a 144 MHz or 430 MHz analog FM amateur rep…
- The radio transmitting equipment used by an amateur radio station must meet the following conditions: (Choose …
- "I am not an amateur radio operator; I applied for a station just for driving convenience and don't need to fo…
- An amateur operator hears what is clearly man-made interfering transmission from a non-amateur station on an a…
- Retransmitting broadcast stations, internet chat, telephone calls, or other stations' contact signals through …
- An amateur station relays messages for other persons, units, or organizations during communication. The correc…
- An amateur radio association broadcasts public-interest notices and technical-training lectures to its members…
- The correct practice regarding the language used during amateur radio communications is:
- May a person who possesses the operating-technical capability prescribed by the national radio management auth…
- Persons who have not obtained the corresponding amateur radio station license or the corresponding operating-t…
- The legal responsibility that an amateur radio station licensee bears for their radio transmitting equipment i…
- The rule that an amateur radio operator must follow when using amateur radio receiving equipment is:
- When an amateur radio operator inadvertently receives information from non-amateur and non-amateur-satellite s…
- May an amateur radio station transmit signals received from broadcast stations, recordings of audio/video prog…
- The state's attitude toward using amateur radio stations to publish or disseminate information that violates t…
- A taxi installs an amateur radio station and uses it to relay information about passengers; the nature of this…
- The proper attitude toward using amateur radio communications to promote amateur radio products or advance oth…
- Using your own amateur station to deliberately jam the normal communications of other amateur stations with a …
- Whether amateur radio activities are conducted in an orderly manner affects the safety and effectiveness of ra…
- Amateur radio stations may be used for the following purposes:
- The group of people who meet the basic conditions of an amateur radio operator is:
- Amateur radio stations are prohibited from engaging in the following activities: (Choose all that apply.)
- Amateur radio stations shall comply with which of the following provisions: (Choose all that apply.)
- Which of the following uses of an amateur radio station exceed the rule of transmitting/receiving signals with…
- Which of the following radio transmitting equipment that has NOT obtained type approval may NOT be established…
- In using an amateur radio station, one may not engage in the following activities: (Choose all that apply.)
- In using an amateur radio station, one shall conform to the following provisions: (Choose all that apply.)
- Regarding the language used during amateur radio communications, the correct practices are: (Choose all that a…
- Which of the following statements about emergency communication by amateur radio stations is correct?
- The conditions under which an amateur radio station is permitted to communicate with non-amateur radio station…
- Amateur radio operators, in responding to emergency incident handling, shall comply with the following provisi…
Supervision and Spectrum Resources监督检查与频谱资源 · 28 questions
- The amateur radio station licensee shall accept supervision and inspection of the amateur radio station and it…
- Which of the following statements about radio spectrum resources is correct? (Choose all that apply.)
- Which of the following statements about radio frequencies, services, and stations is correct? (Choose all that…
- "Whoever, in violation of state regulations, arbitrarily establishes or uses a radio station, or arbitrarily u…
- The use of radio frequencies must be approved by the radio management authority, based fundamentally on "radio…
- Radio control refers to the compulsory management, implemented in accordance with the law, of the emission, ra…
- Radio control refers to the management of which nature, implemented in accordance with the law within a specif…
- When radio control is implemented within a specific time period and area, the management measures related to a…
- The bodies that decide to implement radio control are: (Choose all that apply.)
- Those who violate radio-control orders and radio-control instructions shall be punished in accordance with the…
- An amateur station that violates radio-control orders and instructions may, in accordance with regulations, be…
- For using a radio frequency without authorization, the radio management authority may, according to the specif…
- For arbitrarily establishing or operating an amateur radio station, the radio management authority may, accord…
- Arbitrarily establishing or using a radio station to engage in fraudulent or other unlawful activities may, ac…
- For establishing or operating an amateur radio station not in accordance with the permitted matters and requir…
- For intentionally transmitting or receiving radio signals beyond the matters recorded in the amateur radio sta…
- For arbitrarily compiling or using an amateur radio station call sign, the radio management authority may, acc…
- Where an amateur station interferes with the normal conduct of radio services, the radio management authority …
- Where an amateur station causes harmful interference to radio frequencies involving personal safety, such as d…
- For researching, producing, selling, or repairing high-power radio transmitting equipment without taking effec…
- For overseas organizations or individuals conducting radio-parameter testing or radio monitoring within the te…
- For providing domestic radio-parameter data involving national security to overseas organizations or individua…
- For producing or importing radio transmitting equipment for sale or use within the country that has not obtain…
- For selling radio transmitting equipment that, under Article 44 of these Regulations, should have obtained typ…
- Regarding violations of the Radio Regulations of the People's Republic of China (《中华人民共和国无线电管理条例》), which of t…
- For concealing relevant circumstances, providing false materials, or making false commitments when applying fo…
- For obtaining an amateur radio station license by deceptive, bribing, or other improper means, the following p…
- In the Law on Public Security Administration Punishments of the People's Republic of China (《中华人民共和国治安管理处罚法》),…
Frequency Allocation and Emission频率划分与发射特性 · 50 questions
- When an amateur radio station transmits on a frequency where the amateur service or amateur-satellite service …
- The correct statement about the use of amateur frequencies is:
- In the Table of Frequency Allocations, when a band is allocated to the amateur service or amateur-satellite se…
- In the Table of Frequency Allocations, when a band is allocated to the amateur service or amateur-satellite se…
- The frequency bands allocated by our country exclusively to the amateur service and amateur-satellite service …
- The bands below 30 MHz that our country allocates for shared use between the amateur service (and amateur-sate…
- In the VHF and UHF range, our country allocates the amateur service (and amateur-satellite service) for shared…
- The number of bands our country allocates for shared use with other services where the amateur service is the …
- The bands below 1200 MHz that our country allocates for shared use where the amateur service is a secondary se…
- The highest frequency band allocated by our country to the amateur service and amateur-satellite service, and …
- The international amateur community colloquially calls the three HF bands added to the amateur (and amateur-sa…
- The so-called 40 m amateur band, its frequency ranges in ITU Regions 1, 2, and 3 and the amateur-service usage…
- The frequency range of the so-called 160 m amateur band and the amateur-service usage status are respectively:
- The frequency range of the so-called 80 m amateur band and the amateur-service usage status are respectively:
- The frequency range of the so-called 20 m amateur band and the amateur-service usage status are respectively:
- The frequency range of the so-called 15 m amateur band and the amateur-service usage status are respectively:
- The frequency range of the so-called 10 m amateur band and the amateur-service usage status are respectively:
- The frequency range of the so-called 6 m amateur band and the amateur-service usage status are respectively:
- The frequency range of the so-called 2 m amateur band and the amateur-service usage status in our country are …
- The frequency range of the so-called 0.7 m (70 cm) amateur band and the amateur-service usage status are respe…
- In the frequency allocation of our country and most others, the amateur service is a secondary service sharing…
- The band allocated by our country to the amateur service and amateur-satellite service that falls within the l…
- Short-wave amateur stations should avoid transmitting within ±500 Hz of the IARU beacon operating frequencies.…
- On the 7 MHz band, the frequency range a Chinese short-wave amateur station may actually occupy when conductin…
- On the 14 MHz band, the frequency range a short-wave amateur station may actually occupy when conducting USB v…
- On the 18 MHz band, the frequency range a short-wave amateur station may actually occupy when conducting USB v…
- On the 21 MHz band, the frequency range a short-wave amateur station may actually occupy when conducting USB v…
- On the 24 MHz band, the frequency range a short-wave amateur station may actually occupy when conducting USB v…
- On the ~29 MHz band, the frequency range a short-wave amateur station may actually occupy when conducting USB …
- On the ~29 MHz band, the frequency range a short-wave amateur station may actually occupy when conducting FM v…
- When conducting local contacts on the 144 MHz band, the frequencies a VHF amateur station should avoid occupyi…
- When conducting local contacts on the 430 MHz band, the frequencies a UHF amateur station should avoid occupyi…
- Where the lower frequency limit of a band allocated to the amateur service is F1, the actual transmit frequenc…
- Where the upper frequency limit of a band allocated to the amateur service is F2, the actual transmit frequenc…
- The ITU's attitude toward the 5–30 MHz short-wave bands is:
- The principle laid down by the International Telecommunication Union for determining the radiated power of a t…
- A club has arranged a net frequency for its members to exchange technical information. When another amateur st…
- The ITU Radio Regulations prohibit all stations from emitting the following kind of wave:
- Which of the following illegal acts will be handled by the radio management authority in accordance with the R…
- The principles for amateur stations using amateur-service frequencies are: (Choose all that apply.)
- The lowest band allocated by our country's Radio Frequency Allocation Regulations to the amateur service is 13…
- The 1,800 kHz–2,000 kHz allocated by our country's Radio Frequency Allocation Regulations to the amateur servi…
- The 28 MHz–29.7 MHz allocated by our country's Radio Frequency Allocation Regulations to the amateur service b…
- The 50 MHz–54 MHz allocated by our country's Radio Frequency Allocation Regulations to the amateur service bel…
- The band allocated by our country's Radio Frequency Allocation Regulations to the amateur service that is clos…
- The 430–440 MHz amateur band is closest to the operating frequencies of public walkie-talkies (citizen-band ra…
- The band allocated by our country's Radio Frequency Allocation Regulations to the amateur service that is clos…
- The band allocated by our country's Radio Frequency Allocation Regulations to the amateur service that is clos…
- The band allocated by our country's Radio Frequency Allocation Regulations to the amateur service that is clos…
- The highest band allocated by our country's Radio Frequency Allocation Regulations to the amateur service is 2…
International Radio Regions国际无线电区域划分 · 27 questions
- To divide radio frequencies worldwide, the International Telecommunication Union (ITU) Radio Regulations presc…
- In amateur radio administration we often use the method of dividing the globe into 3 radio-management Regions.…
- The ITU regional division has a detailed set of rules. In summary, it is roughly:
- Amateur frequency allocation differs slightly among the 3 ITU radio-management Regions. The 40 m amateur band …
- Voice contacts on the 2 m band are usually at 144.035–145.800 MHz, which is also a multi-mode shared sub-band …
- Voice contacts on the 2 m band are usually found in 144.035–145.800 MHz. This is also a multi-mode shared sub-…
- In the 70 cm band, amateurs often conduct voice communication in 438–440 MHz. This is also a multi-mode shared…
- In the 70 cm band, amateurs often conduct voice communication in 438–440 MHz. This is also a multi-mode shared…
- In the 10 m amateur band, the segment reserved for the amateur-satellite service, which voice and other commun…
- In the 144 MHz amateur band, the segment reserved for the amateur-satellite service, which voice and other com…
- In the 430 MHz amateur band, the segment reserved for the amateur-satellite service, which voice and other com…
- During a contact, what method lets you clearly convey the English letters in a call sign or important message?
- When a call sign, term, or necessary text must be spelled out, amateur radio operators generally use the spell…
- When a call sign, term, or necessary text must be spelled out, amateur radio operators generally use the spell…
- When a call sign, term, or necessary text must be spelled out, amateur radio operators generally use the spell…
- When a call sign, term, or necessary text must be spelled out, amateur radio operators generally use the spell…
- When a call sign, term, or necessary text must be spelled out, amateur radio operators generally use the spell…
- When a call sign, term, or necessary text must be spelled out, amateur radio operators generally use the spell…
- When a call sign, term, or necessary text must be spelled out, amateur radio operators generally use the spell…
- When a call sign, term, or necessary text must be spelled out, amateur radio operators generally use the spell…
- Amateur radio operators often use the concept of "CQ zone" when calculating DX communication results or applyi…
- Which of the following "CQ zones" lie within China's territory?
- "ITU zones" are the basis for amateur radio operators joining IARU activities and calculating communication re…
- Amateur radio operators sometimes use well-known alternative phonetic alphabets to spell out call signs, names…
- Amateur radio operators sometimes use well-known alternative phonetic alphabets to spell out call signs, names…
- Amateur radio operators sometimes use well-known alternative phonetic alphabets to spell out call signs, names…
- Amateur radio operators sometimes use well-known alternative phonetic alphabets to spell out call signs, names…
CQ Calls and Initiating ContactsCQ 呼叫与发起联络 · 38 questions
- An amateur station should listen before transmitting (monitor first). But sometimes, because you cannot hear o…
- BH1ZZZ wishes to join an ongoing contact between two other stations. The correct method is:
- If during a contact you hear a station in distress requesting to break in, what should you do?
- When requesting to break into a conversation between two stations, a worthwhile rule of thumb is:
- If you find that an amateur station's transmitting operating technique is not quite standard, but it is not ye…
- An amateur station's communication suffers serious interference from an illegal or unidentified station. The c…
- If you have a lot of important technical matters and personal news to exchange with an amateur station several…
- Regulations and international amateur radio practice require the following as the necessary contents of an ama…
- Exchanging QSL cards between amateur radio stations has multiple meanings, including: (Choose all that apply.)
- What contents should a QSL card at least cover? (Choose all that apply.)
- Regarding the use of QSL cards, which of the following statements is correct?
- When you receive a QSL card mailed from overseas and the envelope also contains one or more IRCs (Internationa…
- The correct way to fill in and mail a QSL card is:
- When exchanging QSL cards, we sometimes meet a special kind of radio enthusiast who only sends us a listening …
- When working through a repeater, we should preset the radio's receive/transmit offset in advance, so we can sm…
- If you call a specific amateur station through a repeater, you should:
- The principle for using an amateur repeater is:
- Deep space means space at a distance from the Earth approximately equal to or greater than which of the follow…
- The orbital inclination of an amateur Earth satellite is defined as including:
- The period of an amateur satellite means:
- A geosynchronous satellite means:
- A Sun-synchronous orbit satellite means:
- A geostationary satellite means:
- The direction of a satellite's ascending pass refers to which part of the orbit:
- The direction of a satellite's descending pass refers to which part of the orbit:
- The satellite's period means:
- A satellite's linear transponder means:
- The characteristics of a satellite linear transponder are:
- Sometimes the received satellite downlink strength shows periodic fast fading; this is because:
- After installing satellite-orbit prediction software, the preparation that must be done before predicting a sa…
- A low-Earth-orbit amateur satellite's transponder has limited coverage. The solution for achieving global amat…
- When conducting amateur satellite communication, using transmit power beyond the normal requirement produces w…
- In amateur satellite communication, how do you determine that your current transmit power is appropriate?
- In communication between a ground station and an amateur satellite, the main factor affecting signal strength …
- In amateur satellite communication, the modes called A, B, K, JA, JD, S, T, etc. indicate:
- The concept of "Doppler effect" appears in both amateur satellite communication and amateur radio direction fi…
- When a ground station conducts amateur satellite communication, the Doppler-shift pattern of the received sate…
- Amateur radio satellites are generally placed in low or elliptical orbits. The main reason is:
Calling Procedure and Listening呼叫程序与守听 · 34 questions
- Before initiating a call, an amateur station should listen for a while and then ask "is anyone using the frequ…
- The method for amateur station BH1ZZZ to initiate a CQ call in FM or SSB voice is:
- The method for amateur station BH1ZZZ to initiate a CQ call in voice is:
- The method for amateur station BH1ZZZ to call BH8YYY in voice is:
- After establishing voice communication, operator Xiaoming wants to give the other station BH1ZZZ a signal repo…
- After establishing voice communication, Xiaoming wants to say he is operating from Chengdu. He can say:
- When listening to SSB contacts between amateur radio operators, we sometimes hear short phrases like "Cheerio.…
- If you answer a CQ call in CW, how do you set your sending speed?
- Before initiating a call, an amateur station should listen for a while, then use a brief query to confirm the …
- The way for amateur station BH1ZZZ to send a CQ call in CW or other text mode is:
- The way for amateur station BH1ZZZ to call BH8YYY in CW or other text mode is:
- After establishing a CW contact, Xiaoming gives the other station an RST report of "579". He can send:
- In a CW contact, after receiving the other station's signal report, we usually acknowledge receipt and thank t…
- In everyday CW contacts, we thank the other party for the nice contact; we can send:
- In CW contests or DX contacts, we thank the other party for the contact. We can send:
- During a CW contact, Xiaoming wants to introduce his name. He can send:
- In CW contacts, the abbreviation "OP" means the operator's name. When Xiaoming introduces his name to the othe…
- In a CW contact, if you know the other operator's name (or they have introduced themselves), you may prefix it…
- In contacts, amateurs often use words like "receiver", "transmitter", "transceiver", and "equipment" to descri…
- In a CW contact, Xiaoming wants to tell the other station his equipment is an X6200. He can send:
- In amateur radio abbreviations, "PWR" means "power". To ask the other station how much transmit power they are…
- The amateur-radio abbreviation "ABT" means "about" or "approximately". If, during a contact, you want to tell …
- The amateur-radio abbreviation "ANT" means "antenna". If you want to tell the other station that you are using…
- When operating in CW or other text modes, we sometimes use the abbreviation "WX" to exchange weather informati…
- During a CW contact, if you want to know how well the other station is copying your signal, besides "QSL ?", y…
- In a CW contact, if the other station copies your message perfectly, they will tell you in their reply using t…
- During a contact, if you want to find out whether your signal is experiencing interference from other stations…
- During a contact, if you want to tell the other station that its signal is experiencing interference from othe…
- During a contact, if you want to find out whether your signal is experiencing atmospheric (static) interferenc…
- During a contact, if you want to tell the other station that its signal is experiencing atmospheric (static) i…
- During a CW contact, the other station sometimes sends the symbol "di-dah di-di-dit". It looks like "AS" sent …
- During a contact, if you receive the short phrase "PSE QSL VIA BURO" sent by the other station, then the "QSL"…
- When ending the current contact and bidding each other farewell, amateur radio operators often use the abbrevi…
- When ending a CW session, we often hear the other station send the symbol "di-di-di dah-di-dah". It looks like…
Q Codes and AbbreviationsQ 简语与常用缩语 · 82 questions
- During QRP operation, if the other station reports your signal is weak, you might ask whether you should incre…
- During a contact, if you believe QRP operation is enough to ensure reliable communication, you can negotiate w…
- When amateur stations conduct communication research or chase awards at power below 5 W, they often append the…
- During a contact, if you want the other station to increase its sending speed, you can send:
- During a contact, if the other station asks you to increase sending speed, you can confirm by asking back. You…
- During a contact, if you want the other station to reduce its sending speed, you can send:
- During a contact, if the other station asks you to reduce sending speed, you can confirm by asking back. You c…
- When ending the day's operating activity, an amateur station often sends the Q-code "QRT". Its meaning is:
- Before ending a contact, we may ask the other party whether there is any further message to convey. At this po…
- When ending a contact, we can tell the other party that there is nothing further here. At this point we may se…
- During a contact, if you wish to ask the other party to join in some amateur radio activity (e.g., "Mulan Weic…
- The meaning of the Q-code "QRV" is:
- When making a call, if you did not hear the other station's call sign clearly, you may use the following phras…
- The meaning of the Q-code "QRZ" is:
- Reading early Chinese amateur radio literature, we may encounter a signal report expressed with a Q-code and f…
- During a contact, if you want to find out whether your signal is fading, you may use the phrase:
- The meaning of the Q-code "QSB" is:
- Xiaoqiang and Xiaoming are practicing CW. If Xiaoqiang asks "Do I have a fault in my sending technique?", he c…
- Xiaoqiang and Xiaoming are practicing CW. Xiaoming thinks Xiaoqiang's technique was poor when sending the lett…
- Xiaoqiang and Xiaoming are practicing CW. Xiaoming thinks Xiaoqiang's sending has a thumping key-click sound. …
- The meaning of the Q-code "QSK" is:
- During a contact, if you need the other station to confirm that it received your message, you may use the phra…
- The meaning of the Q-code "QSL" is:
- The meaning of the Q-code "QSO" is:
- During a contact, if you want to find out whether the other station can help relay a message to "station xxx",…
- The meaning of the Q-code "QSP" is:
- During a contact, if Xiaoming wants Xiaoqiang to help listen out for his FT8 operation on 7074 kHz, he can sen…
- When Xiaoqiang tells Xiaoming that he is listening for FT8 contacts on 7074 kHz, he can send:
- During a contact, if you need to negotiate with the other party to change frequency to nnnn kHz (or MHz), you …
- The meaning of the Q-code "QSY" is:
- During a contact, if you want to know the other station's location, you may use the phrase:
- When ending the current contact and exchanging good wishes, amateur radio operators often use the abbreviation…
- If, during a CW or other text-mode contact, you must ask the other party for the mailing address for their QSL…
- If you need the other party to repeat the previous operation, such as re-sending the call sign or the signal r…
- The meaning of the amateur-radio abbreviation "AHR" is:
- The abbreviation for "amateur radio direction finding" is:
- When exchanging QSL information during a CW contact, we may use the term "post office box." Its abbreviation i…
- The abbreviation for "QSL card bureau (manager)" is:
- In a CW contact, we sometimes copy the abbreviation "CK", which means:
- The abbreviation an amateur station uses when making a general call is:
- When describing a signal coming from a distant place, amateurs often use the abbreviation:
- In a CW contact, we sometimes copy the abbreviation "ES", which means:
- In a CW contact, we sometimes copy the abbreviation "FB", which means:
- In a CW contact, we sometimes copy the abbreviation "FER", which means:
- The abbreviation for the term "frequency" is:
- After establishing a CW contact, we often greet the other party while exchanging signal reports. The abbreviat…
- After establishing a CW contact, we often greet the other party while exchanging signal reports. The abbreviat…
- When ending the current contact and wishing the other party good luck and good results, amateur radio operator…
- The meaning of the amateur-radio abbreviation "GLD" is:
- After establishing a CW contact, we often greet the other party while exchanging signal reports. The abbreviat…
- Sometimes, the DX station we contact still uses "GMT" to express time. The meaning of this time is:
- The meaning of the amateur-radio abbreviation "GN" is:
- The meaning of the amateur-radio abbreviation "GND" is:
- In late December each year, we often hear the abbreviation "HNY" in CW contacts, which means:
- In a CW contact, we sometimes copy the abbreviation "HPE", which means:
- In a CW contact, we sometimes copy the abbreviation "HPY" or "HPI", which means:
- The abbreviation for "high-speed telegraphy" is:
- When an amateur station finishes its current transmission and listens for any station, it should use the abbre…
- When an amateur station finishes its current transmission and listens only for the other station in the contac…
- To express "thank you very much" in a CW contact, we send:
- The meaning of the amateur-radio abbreviation "NW" is:
- During contacts, we sometimes call the other operator "old man." This likens the other party to a close comrad…
- The abbreviation for "operator" is:
- In daily CW (continuous wave) contacts, appropriately using imperative sentences that include the word "please…
- Similar to "QSL", if you have completely copied the message sent by the other station, we often start a new ex…
- In the amateur radio service, the meaning of "SAE" is:
- When amateur radio operators mail QSL cards, they often mention the abbreviation "SASE", whose meaning is:
- In a contact, if you need to correct content you just sent wrongly, you usually start the exchange with "sorry…
- The abbreviation for "temperature" (温度) is:
- The abbreviation for "thank you" (谢谢) is:
- The abbreviation for "thank you" (谢谢你, short) is:
- "Your" or "you are" can be expressed by the abbreviation:
- In CW contacts, we sometimes copy the abbreviation "WL", which means:
- Listening to CW or SSB contacts, we sometimes hear the abbreviation "XYL". Its meaning is:
- There is a class of amateur radio operators honored with the title "YL", and some amateur radio contests have …
- The term "element" (单元) usually refers to an antenna element (radiator). Its abbreviation is:
- When discussing antennas in amateur radio contacts, the abbreviation DP stands for:
- When discussing antennas in amateur radio contacts, the abbreviation GP stands for:
- When discussing antennas in amateur radio contacts, the abbreviation VER stands for:
- When discussing antennas in amateur radio contacts, the abbreviation LW stands for:
- When discussing antennas in amateur radio contacts, the abbreviation YAGI stands for:
- When discussing antennas in amateur radio contacts, the abbreviation BEAM stands for:
Emission Classes发射类别 · 49 questions
- "Class of emission" means a set of characteristics of an emission designated by standard symbols, e.g., the ma…
- "Class of emission" means a set of characteristics of an emission designated by standard symbols, e.g., the ma…
- "Class of emission" means a set of characteristics of an emission designated by standard symbols, e.g., the ma…
- "Class of emission" means a set of characteristics of an emission designated by standard symbols, e.g., the ma…
- "Class of emission" means a set of characteristics of an emission designated by standard symbols, e.g., the ma…
- "Class of emission" means a set of characteristics of an emission designated by standard symbols, e.g., the ma…
- Out-of-band emission means:
- In amateur radio communication the three most basic modulations are abbreviated AM, FM and PM. Their Chinese n…
- Which modulation is widely used for VHF or UHF local contacts?
- Which modulation is widely used for long-distance and weak-signal VHF or UHF voice contacts?
- Which modulation is widely used for HF voice contacts?
- What is the advantage of SSB compared with FM?
- What is the main disadvantage of FM compared with SSB?
- For SSB contacts on VHF and UHF bands, which sideband is usually selected?
- For voice communication on HF bands of 14 MHz and above, which sideband is usually selected?
- For voice communication on bands of 7 MHz and below, which sideband is usually selected?
- Why do amateur stations use lower sideband for voice below 10.1 MHz but upper sideband above 10.1 MHz?
- When initiating an SSB call, the frequency separation between you and nearby stations should be at least:
- Which of the following modulation modes can be classified under amplitude modulation (AM)?
- In the amateur radio service there is a communication mode abbreviated CW. Its meaning is:
- Which modulation mode has the narrowest emission bandwidth?
- Amateur stations generally do not use FM phone for Morse code contacts. This is because:
- Whether FM or SSB modulation, applying an audio signal 10 times the specified input voltage to the microphone …
- Amplitude modulation (AM) is a simple modulation because only the amplitude of the RF carrier varies following…
- An AM signal has not only the lower or upper sideband corresponding to the modulating signal, but may also con…
- A voice signal is modulated by a USB transmitter into an RF signal. From a frequency-domain perspective, this …
- A voice signal is modulated by an LSB transmitter into an RF signal. From a frequency-domain perspective, this…
- Frequency modulation (FM) is a simple modulation because only the frequency of the RF carrier varies following…
- Which of the following determines the frequency deviation of an FM signal?
- Phase modulation (PM) is a simple modulation because only the phase shift of the RF carrier varies following t…
- For a given FM amateur station, the factor that determines its actual transmitted bandwidth is:
- For a given SSB amateur station, the factor that determines its actual transmitted bandwidth is:
- In the amateur radio service, the speed of Morse code signals is often measured in WPM; the method of measurem…
- In the amateur radio service, the signal-timing standard used when calculating the WPM speed of Morse code (wi…
- The necessary emission bandwidth of a CW signal can be calculated using the formula Bn = B × K. Here, B is the…
- The necessary emission bandwidth of a CW signal can be calculated using the formula Bn = B × K. Here, the cons…
- The necessary bandwidth Bn of FM voice depends on the peak frequency deviation D of the FM signal and the high…
- The modulation methods used for slow-scan television (SSTV) and radio facsimile (FAX) in the amateur bands are…
- What amateur radio slow-scan television transmits is:
- A certain amateur station intends to transmit several circuit diagrams with a resolution of 1024×768 pixels or…
- When receiving SSTV signals in modes such as Robot, Scottie, Martin, SC2, or PD, we hear a periodic, very brie…
- SSTV communication provides different transmission modes such as Robot, Scottie, AVT, and Martin. The specific…
- The method of conducting SSTV contacts using a personal computer (PC) and an ordinary voice transceiver is: (C…
- The baseband signal of slow-scan television (SSTV) is normally generated within the audio range and transmitte…
- If the received SSTV or ATV image shows thick horizontal black stripes and the upper and lower half-frames are…
- If the received SSTV or ATV image is tilted left-right, appearing as a parallelogram or slanted thick-stripe p…
- Why can't regular ATV communication be conducted in amateur bands below 1.2 GHz?
- Sometimes, amateur radio operators use FM instead of the classic VSB method commonly used in TV broadcasting t…
- Sometimes, amateur stations use VSB to transmit analog ATV signals. Although this method belongs to AM, it sen…
Digital Communication Modes数字通信方式 · 48 questions
- Yaesu System Fusion, abbreviated YSF, is a communication mode integrating digital voice and data transmission.…
- The Icom D-STAR System provides a data communication mode, whose characteristics are: (Choose all that apply.)
- FreeDV is a digital voice mode. Its characteristics are: (Choose all that apply.)
- Digital amateur television (DATV) is a mode applying digital audio/video compression coding to real-time image…
- When using the DRM protocol for digital slow-scan television (DSSTV) communication, amateurs always tend to tr…
- The class of emission refers to a set of characteristics of an emission designated by means of standard symbol…
- The class of emission refers to a set of characteristics of an emission designated by means of standard symbol…
- The class of emission refers to a set of characteristics of an emission designated by means of standard symbol…
- The main considerations in choosing different modulation methods for amateur radio communication are: (Choose …
- To satisfy the requirement of "technical characteristics of stations" in our Radio Frequency Allocation Regula…
- Which of the following services use data modes for communication? (Choose all that apply.)
- Frequency-shift telegraphy refers to: a frequency-modulation telegraph technique in which the telegraph signal…
- The modulation method of RTTY is:
- Digital communication often involves the two parameters "symbol rate", which describes the change of signal st…
- Digital communication often involves the two parameters "symbol rate", which describes the change of signal st…
- Digital communication often involves the two parameters "symbol rate", which describes the change of signal st…
- Digital communication often involves the two parameters "symbol rate", which describes the change of signal st…
- Some commonly used amateur radio digital communication protocols only support the transmission of 5-bit or 7-b…
- Among the error-control techniques in amateur data communication there are two kinds: "forward error correctio…
- Among the error-control techniques in amateur data communication there are two kinds: "forward error correctio…
- The method of conducting RTTY contacts using a personal computer (PC) and an ordinary voice transceiver is:
- The operating method for conducting PSK31 contacts using a personal computer (PC) and an ordinary voice transc…
- The operating method for conducting HF PACKET contacts using a personal computer (PC) and an ordinary voice tr…
- PACKET is an amateur radio communication mode developed by enthusiasts using the AX.25 packet communication pr…
- In VHF packet communication (PACKET), which modulation mode is most widely used?
- APRS signals frequently appear on the 2 m amateur band. Their main purpose is:
- Compared with binary serial modes such as RTTY and APRS, the method of simultaneously transmitting multiple bi…
- If messages are transmitted at the same information transfer rate, the symbol rate when using MFSK16 is lower …
- According to whether the clocks at the transmitting and receiving ends of serial data communication are kept r…
- According to whether the clocks at the transmitting and receiving ends of serial data communication are kept r…
- When performing serial asynchronous digital communication, both sides must set the same baud rate, number of d…
- RTTY, as often called by amateur radio operators, is also known as frequency-shift telegraphy — a frequency-sh…
- International Telegraph Alphabet No. 2 (ITA2) has always played an important role in the amateur radio service…
- What is PSK31?
- The modulation method of PSK31 is:
- What is FT8?
- The modulation method of FT8 is:
- Regarding the digital communication mode JT65, which of the following descriptions is correct: (Choose all tha…
- FT8 signals are commonly found on HF and VHF amateur bands. The advantages of this mode are: (Choose all that …
- When answering a station's FT8 call, how should we use the waterfall display provided by the logging software …
- FT4 is a communication mode similar to FT8. Its characteristics are: (Choose all that apply.)
- When preparing for FT8, FT4, or JT65 contacts, we need to feed the audio baseband output of the logging softwa…
- An amateur radio station transmits in FM with an RF output power of 10 W, and its power-supply efficiency is a…
- An amateur radio station transmits in CW with a carrier output power of 10 W, and its power-supply efficiency …
- An amateur radio station transmits in SSB with a peak output power of 10 W, and its power-supply efficiency is…
- An amateur radio station transmits in SSB with a peak output power of 10 W, and its power-supply efficiency is…
- An amateur radio station transmits in SSB with a peak output power of 10 W, and its power-supply efficiency is…
- An amateur radio station transmits in SSB with a peak output power of 10 W, and its power-supply efficiency is…
DX and Contest OperatingDX 与竞赛操作 · 42 questions
- How do you call all DX stations?
- Which of the following describes good habits for participating in DX contacts and amateur radio contests?
- Participating in DX net communication helps establish contacts with some rare stations. The correct practice i…
- If there is an unavoidable strong noise source near a short-wave amateur station that affects reception of wea…
- BD0ZZ hears a CW call from an amateur station and wishes to contact it. However, he only caught the district n…
- BD0ZZ hears an SSB call from an amateur station and wishes to contact it. However, he only caught the district…
- The meaning of the DX Summit message "PY2SS 28005.3 KH6/N6GQ simplex, fading signal in SA 2040 15 Feb 2012" is…
- The meaning of the DX Summit message "JA2WS 14009.6 E51WWA Calling CQ, no takers, Cook Is 0052 14 Feb 2018" is…
- SSTV contacts on the 20 m band are most commonly found at:
- IOTA activity on the 20 m band is most commonly found at:
- According to contest convention, the frequencies generally NOT used for the IOTA contest are:
- Generally speaking, the best time period for 10 m band DX communication is:
- When applying for the WAS (Worked All States) award, which of the following call-sign cards cannot be used as …
- To apply for the 5-band WAZ award (5BWAZ), at least how many zone cards must be submitted:
- For amateur radio operators in our country, which of the following stations is the rarest and most difficult t…
- To apply for the satellite and 6 m WAZ awards, at least how many zone QSL cards must be submitted?
- To apply for the 160 m WAZ award, at least how many zone QSL cards must be submitted?
- On 14022 kHz many stations are eagerly sending their call signs. They are calling a rare station whose transmi…
- Taking Beijing as the center, the great-circle distances to the DXCC entities 3X, HZ, G, and OE, arranged from…
- When we use a directional antenna to contact amateur stations in Europe, we often point the antenna toward rou…
- To erect a horizontally polarized half-wave dipole in Beijing in an attempt to contact amateur stations in New…
- A fragment of a certain amateur station's CW signal is "B1CRA TEST UP 5", meaning:
- During an HF contest, answering a contest station's CQ is a basic operation. We can first listen to it for a w…
- In the CQ WW contest, which of the following categories is NOT allowed to use CW Skimmer to assist in finding …
- If during the IARU HF World Championship you hear a station sending "5NNJARL", its call sign is most likely:
- A 20-year-old female university student from Beijing participates in the IARU HF World Championship SSB single…
- A 20-year-old female university student from Beijing participates in the ALL ASIAN DX CONTEST SSB single-opera…
- A 20-year-old female university student from Beijing participates in the CQ WW CW contest. A signal report she…
- If during an amateur radio contest you hear the exchange message "599NJ", the contest is likely to be:
- Amateur radio operators often use the Maidenhead Grid Square Locator to indicate their station's location. For…
- The Maidenhead grid locator system used in amateur radio contacts may have the encoding format:
- The encoding amateur radio operators use to mark their own station location with the Maidenhead grid locator m…
- To facilitate time calculation, the Earth is divided into several time zones; the method of dividing each theo…
- To facilitate time calculation, the Earth is divided into time zones; the naming rule of each theoretical time…
- To facilitate time calculation, the Earth is divided into time zones; Beijing's situation is:
- To facilitate time calculation, the Earth is divided into time zones; the theoretical division is 15 degrees p…
- Given Beijing time, the corresponding UTC time should be:
- Given UTC time, the corresponding Beijing time should be:
- Given an amateur station is in a West-N time zone (N an integer from 0 to 12), its local time should be ___ th…
- Given an amateur station is in an East-N time zone (N an integer from 0 to 12), its local time should be ___ t…
- If while participating in an amateur radio CW contest you copy "B4" or "WKD", it means:
- Why should everyone submit logs promptly when participating in contests?
Transceivers and Receiver Systems收发信机与接收系统 · 33 questions
- If the surroundings are noisy during SSB or CW communication (QSO), which device can replace the radio's speak…
- Full-featured small transceivers often have functions abbreviated "NB" and "SQL" on the panel. What is the dif…
- Some vehicles' spark plugs radiate impulse interference. This may cause the receiver's AGC to act too early, s…
- What function does "MODE" on the panel of a full-featured small transceiver represent?
- What function does the symbol ATT on the transceiver panel represent?
- What function does the symbol AGC on the transceiver panel represent?
- Since full-featured receivers have AGC, why do many models also have an attenuator (ATT) switch?
- Regarding the receiver "overload" phenomenon, which of the following descriptions is correct? (Choose all that…
- The situation in which the receiver's AGC function should be turned off is:
- The situation in which a shorter AGC time constant should be selected is:
- The situation in which a longer AGC time constant should be selected is:
- On most small full-featured transceivers you can see the symbol PRE on the panel. What function does it repres…
- What function does the symbol ALC on the transceiver panel represent?
- In an SSB transmitter, what is the main function of transmit automatic level control (ALC)?
- When an amateur station conducts SSB voice communication, if the other party reports that although your speech…
- Even with the transmitter's ALC turned on, setting the microphone gain too high can still lead to:
- Why is it necessary to turn off ALC when sending AFSK signals with an SSB transceiver?
- What is the function of the speech compression feature in an SSB transmitter?
- What function does the symbol PROC on the transceiver panel represent?
- When transmitting, what problem may improper adjustment of speech compression cause?
- Why should the speech compression function be turned off when sending AFSK signals with an SSB transceiver?
- When an amateur station measures transmit power and antenna SWR by transmitting, what must be noted and done i…
- An SSB amateur station needs to transmit a steady continuous signal to test and check the antenna SWR. The cou…
- What function do the symbols AT or TUNE on the transceiver panel represent?
- When listening with a communications receiver that has separate RF/IF gain and audio gain controls, you can se…
- Compared with VHF or UHF communication, what is the biggest difference of HF communication?
- Which of the following methods can reduce the RF current that may be induced in the audio cable of a microphon…
- When an amateur repeater shares one antenna for uplink and downlink, a ___ must be inserted between the receiv…
- When an amateur repeater shares one antenna for uplink and downlink, a duplexer is inserted between the receiv…
- Before erecting an amateur repeater you must check whether there are nearby transmitters on other frequencies …
- A certain amateur repeater's transmitter is often triggered by intermittent interference signals, mixed with i…
- Once an FM amateur repeater's transmitter is started by an uplink signal, it keeps transmitting even after the…
- An FM amateur repeater's transmitter can be normally started by an uplink signal. But after the uplink signal …
Transceiver Front-Panel Controls收发信机面板控制 · 24 questions
- The Chinese name of RIT on the amateur transceiver panel and its meaning are:
- The Chinese name of XIT on the amateur transceiver panel and its meaning are:
- The Chinese name of SPLIT on the amateur transceiver panel and its meaning are:
- For what scenarios is the split (SPLIT) operation mode of an amateur station mainly used? (Choose all that app…
- Which function can make an SSB or CW signal that sounds high or low in pitch become normal?
- Some transceivers have a CW-R function that reverses the sideband used when receiving CW. This function is ben…
- Some transceivers have a QSK function, i.e. "full break-in". The specific meaning is:
- What is the advantage of a receiver with multiple bandwidth selections?
- An amateur receiver's IF filter bandwidth offers choices of 100 Hz, 400 Hz, 2.7 kHz and 6 kHz. If choosing app…
- We always want the receiver's receive bandwidth to match the necessary bandwidth of the current operating mode…
- When participating in VHF amateur radio contests or EME communication experiments, we may need to add an exter…
- Where in the amateur radio equipment should an external low-pass filter used to enhance rejection of spurious …
- When conducting multi-operator multi-station HF contests, to prevent as much as possible the transmitter's har…
- A stub filter, sometimes called a branch-line filter (coax stub), is a band-pass or band-reject filter made fr…
- Some transceivers have an RX ANT connector. This connector is used to:
- Some transceivers have a built-in auxiliary receiver, mainly used for: (Choose all that apply.)
- Diversity reception uses multiple receivers to simultaneously capture the same signal, to obtain more complete…
- When participating in contests or DX contacts, we may need a standalone SDR receiver to assist CW or FT8 decod…
- Which interfaces are used when interconnecting a transceiver and a linear power amplifier? (Choose all that ap…
- Why is it necessary to connect an automatic level control (ALC) line when using a linear power amplifier?
- When using an HF linear power amplifier in a multi-station contest environment, we try to improve the purity o…
- The general method for adjusting an electron-tube (vacuum-tube) HF linear power amplifier is:
- Properly produced electron-tube HF linear amplifiers generally connect a very large inductance RF choke to gro…
- The inner side of the chassis cover of an electron-tube linear amplifier usually has an interlock switch. Remo…
Antenna Fundamentals天线的作用 · 70 questions
- The function of a transmitting antenna is:
- The function of a receiving antenna is:
- Regarding antenna gain, which of the following statements is correct? (Choose all that apply.)
- Antenna gain expressed in dBi means:
- What is an "ideal point-source antenna"? And what is its significance for amateur radio?
- Antenna gain expressed in dBd means:
- The half-wave dipole is a practical antenna capable of radiating radio waves. To obtain the lowest input imped…
- The antenna gain indicator given in a certain commercial antenna manual is expressed in dB. Its meaning is:
- The reason we call a vertical grounded antenna an "omnidirectional antenna" is:
- If a vertically grounded (ground-plane) antenna is required to have a main lobe at a horizontal launch angle o…
- Regarding the maximum-radiation direction of a vertically grounded (ground-plane) antenna whose element is 1/4…
- Which of the following statements about the "rubber-duck" antennas supplied with most handheld transceivers is…
- What problem may be encountered when using a handheld transceiver with a flexible "rubber-duck" antenna for co…
- If, when erecting an antenna, you find mains-powered equipment such as power lines near the site, what should …
- The vertically grounded antenna (GP) consists of a vertical element with an electrical length of 1/4 wavelengt…
- Which of the following descriptions about antenna loading is correct?
- The element of a resonant vertically grounded antenna must be at least 1/4 wavelength long. If site constraint…
- Antenna A has a gain of 6.15 dBi and antenna B has a gain of 1 dBd. If both antennas are erected under the sam…
- Antenna A has a gain of 0 dBd and antenna B has a gain of 2 dBi. If both are erected under the same conditions…
- Two VHF vertical omnidirectional antennas are used for transmitting. Antenna A has a gain of 4.5 dBd and anten…
- Two VHF vertical omnidirectional antennas are used for transmitting. Antenna A has a gain of 2.9 dBd and anten…
- When amateur radio operators discuss antenna systems they often mention the term "standing-wave ratio (SWR)". …
- During a contact, if the transceiver's SWR meter reads 4:1, this means:
- Xiaoqiang uses a 50 Ω feed line no shorter than 1/4 wavelength to connect the transceiver and antenna. While t…
- Most transmitters reduce output power when the SWR exceeds a certain value. This is in order to:
- When connecting an antenna with coaxial cable, why is it better for the SWR to approach 1:1?
- Which of the following situations may cause the SWR displayed by an amateur transmitter to be unstable?
- During SSB contacts, even when the antenna/feed system has no fault, the SWR reading is sometimes unstable. Th…
- We all know the feed line between transmitter and antenna should match the antenna impedance. Otherwise, stand…
- For amateur radio communication, the most suitable characteristic impedance of coaxial cable is:
- Transmission lines come in many types, but why is coaxial cable usually chosen when setting up an amateur stat…
- When purchasing coaxial cable for use as an antenna feed line for an amateur station, which electrical paramet…
- We all know to choose a low-loss feed line for the amateur station. But what problems can feed-line loss cause…
- Moisture ingress is a main cause of coaxial cable failure and damage. Moisture penetration can cause: (Choose …
- When installing coaxial cable outdoors, why is the cable jacket required to resist ultraviolet (UV) light?
- Compared with coaxial cable filled with organic dielectric, what is the disadvantage of air-dielectric coaxial…
- If the signal frequency passing through a coaxial cable rises, the coaxial cable's:
- Several feed lines of equal outer diameter are listed below. Which has lower loss in the VHF/UHF bands?
- For signals at 400 MHz or higher, the coaxial connector that should be preferred is:
- Which of the following statements about the Type M coaxial connector is correct?
- Which of the following statements about a vertical antenna is correct? (Choose all that apply.)
- Which of the following descriptions about a horizontally polarized dipole antenna is correct? (Choose all that…
- Stations A and B are 10 km apart, both using 1/2-wavelength horizontal dipole antennas for UHF communication. …
- Stations A and B are 10 km apart, using 1/2-wavelength horizontal and vertical dipole antennas respectively fo…
- Stations A and B are 10 km apart, using 1/2-wavelength horizontal and vertical dipoles respectively for UHF. N…
- Stations A and B are 10 km apart, using left-hand and right-hand circularly polarized antennas pointed at each…
- Stations A and B are 10 km apart, using left-hand and right-hand circularly polarized antennas pointed at each…
- Stations A and B are 10 km apart, using left-hand circular polarization (A) and a half-wave horizontal dipole …
- Stations A and B are 10 km apart, using left-hand circular polarization (A) and a half-wave horizontal dipole …
- Stations A and B are 10 km apart, using left-hand circular polarization (A) and a half-wave horizontal dipole …
- Stations A and B are 10 km apart, using left-hand circular polarization (A) and a half-wave horizontal dipole …
- Stations A and B are 10 km apart, using left-hand and right-hand circularly polarized antennas pointed at each…
- Assume both receiving and transmitting antennas use half-wave dipoles. For short-distance communication betwee…
- A right-hand polarized wave means, on any plane perpendicular to the direction of propagation, when viewed alo…
- In line-of-sight communication, given the transmitting antenna is a left-hand circularly polarized antenna poi…
- A satellite's downlink uses a right-hand circularly polarized antenna, flies from north to south, and the ante…
- It is known that a satellite's downlink transmitting antenna is a dipole pointing at the ground. Because the s…
- An amateur station using a half-wave vertical dipole for a contact receives an S4 signal strength at the other…
- An amateur station transmitting with a half-wave vertical dipole yields an S4 received signal at the other end…
- Two amateurs use half-wave vertical dipoles to contact each other; each receives the other's signal at S4. Now…
- Even on an open plain or vast desert, the strength of locally received VHF/UHF signals changes periodically as…
- A phenomenon in VHF/UHF contacts: if a distant station gives a poor signal report, merely moving a few steps o…
- The effect of multipath propagation on UHF or VHF data communication is:
- When using VSB (vestigial sideband) for ATV (amateur television) communication, even when the signal is relati…
- The main factor that determines the maximum range of ultra-short-wave (VHF/UHF) line-of-sight propagation is:
- Sometimes amateur stations hundreds of kilometres apart can make VHF/UHF beyond-line-of-sight direct contacts.…
- Sometimes we can receive "beyond-line-of-sight propagation" signals from over a thousand kilometres away on th…
- What causes tropospheric atmospheric ducting?
- If you receive a VHF signal from over a thousand kilometres away, the most likely reason is:
- Sometimes "beyond-line-of-sight propagation" signals up to 500 km away may appear in VHF/UHF amateur bands. Th…
Antenna Systems and Matching天线系统与匹配 · 42 questions
- The ideal operating state of an antenna system composed of a half-wave dipole and a transmission line should b…
- The end effect of antenna elements, phase shift of signals, etc., affect the speed of electromagnetic wave pro…
- To make a half-wave dipole antenna operating at frequency f (in MHz). The length of each element arm (in meter…
- The propagation speed of radio waves in a medium is lower than the speed of light; its ratio to the speed of l…
- To build a certain phased antenna array operating at frequency f (in MHz), a coaxial cable of 1/4 wavelength i…
- If a dipole antenna is to have low input impedance when resonant at the operating frequency, the total length …
- The necessary and sufficient condition for a dipole antenna to resonate at the desired operating frequency is:
- Which of the following resonant dipole antennas has peak gain in the direction perpendicular to the element?
- The method to raise a dipole antenna's resonant frequency is:
- Between the antenna and feed line a component commonly called a "balun" is often inserted. The origin of "balu…
- Between the antenna and feed line a component commonly called a "balun" is often inserted. Its main function i…
- A dipole whose two arms each have an electrical length of 1/4 wavelength, with the center broken and fed via a…
- A horizontally polarized dipole oriented north–south, center-fed, connected via 50-ohm cable to a 50-ohm trans…
- The launch (takeoff) angle of short-wave horizontal dipole antennas (including Yagi, etc.) is mainly determine…
- When erecting a short-wave antenna, the launch angle should roughly be chosen according to:
- When erecting a short-wave antenna, the antenna height should roughly be planned according to:
- In DX communication aimed at a specific target, the basic method to calculate the antenna's optimal launch ang…
- The effect of ground conductivity around the transmitting/receiving antenna on long-distance HF communication …
- If the height of a horizontal dipole antenna is lowered to 1/10 wavelength above ground, what change occurs in…
- On a good conducting ground, the main factor affecting the radiation elevation angle of a short-wave (HF) ante…
- When building your own HF dipole, if space limits prevent spreading the element to its natural resonant length…
- The figure shows a 14/21/29 MHz triband dipole commonly used by Chinese amateur radio operators for field-comm…
- The figure shows the 14/21/29 MHz triband dipole commonly used by Chinese amateur radio operators for field co…
- The element of a resonant dipole must be at least half a wavelength long. If erection space forces you to shor…
- For amateur services that must change bands frequently, operators sometimes parallel the dipoles of the used b…
- What is a Yagi antenna (八木天线)?
- A Yagi is a directional antenna made by adding directors and a reflector to a normal dipole (driven element). …
- How is the front-to-back ratio (前后比) of a Yagi antenna defined?
- A traveling-wave antenna radiates as RF current travels along a continuously matched long-wire structure. Comm…
- Traveling-wave antennas commonly used in amateur radio, such as the T2FD and the Beverage (贝伐列奇), have a non-i…
- Xiaoming connects a coil at the midpoint of a 20 m wire and lifts the wire horizontally to a hanging position …
- To lower the radiation elevation angle, Xiaoming hangs half of the T2FD dipole vertically. He connects the fol…
- Which of the following statements about a loop antenna is correct?
- If the space for erecting an antenna is limited, a magnetically coupled tunable loop antenna may be an option.…
- During field operations or emergency-communication drills, amateurs may find that contacting HF stations 100–2…
- What is the function of a transceiver-built-in or connected antenna tuner (天线调谐器, colloquially 天调)?
- Regarding the claim that an antenna tuner (天调) improves contacts, which of the following descriptions is corre…
- An antenna is connected via a 50 Ω feed line to a 50 Ω-output transceiver. You plan to insert an antenna tuner…
- A tower-top antenna is connected via 50 Ω feed line to a 50 Ω-output transceiver. You must insert an antenna t…
- Footnote 5.67A of the Radio Frequency Allocation Regulations of the PRC (《中华人民共和国无线电频率划分规定》) says: amateur-ser…
- An antenna has a gain of 3.85 dBd and 10 W is fed into it. Its equivalent isotropically radiated power (EIRP) …
- An antenna has a gain of 5.15 dBi and 10 W is fed into it. Its effective radiated power (ERP) is:
Transmission Lines传输线 · 58 questions
- Transmission lines are commonly used to connect the station and the antenna. The more common transmission line…
- Regarding the characteristic impedance of coaxial cable, which of the following statements is correct? (Choose…
- A 50 Ω coaxial cable is terminated at its far end with a 50 Ω load resistor. If you measure the near-end imped…
- A 50 Ω coaxial cable is left open at its far end. If you measure the near-end impedance at different frequenci…
- A 50 Ω coaxial cable is short-circuited at its far end. If you measure the near-end impedance at different fre…
- When measuring a mismatched antenna's impedance with an antenna analyzer, you will find the reading changes wi…
- The electric field produced by a source (e.g., an antenna) creates a displacement current, exciting a varying …
- The two components of an electromagnetic wave are:
- How fast do radio waves travel in a vacuum?
- When an electromagnetic wave propagates in a vacuum, the distance it travels in each cycle is the same. This d…
- If the frequency of a radio wave is known, its wavelength is:
- Regarding the frequency, period, and wavelength of radio waves, which of the following descriptions is correct…
- Radio waves in free space gradually weaken as the propagation distance increases. What law does the degree of …
- Radio waves in free space spread and weaken with distance, forming path loss. The loss can be described as L =…
- In free space, stations A and B are 100 km apart, both using 0 dBi antennas at 145 MHz. If the transmitter pow…
- In free space, stations A and B are 100 km apart, both using 0 dBi antennas at 145 MHz. If the transmitter pow…
- In free space, stations A and B are 100 km apart, both using 0 dBi antennas at 145 MHz. If the transmitter pow…
- In free space, stations A and B are 100 km apart, both using 0 dBi antennas at 145 MHz. If the transmitter pow…
- In free space, station A contacts station B 100 km away on 145 MHz and receives an S8 report. If the distance …
- In free space, station A contacts station B 100 km away on 145 MHz and receives an S8 report. If the distance …
- In free space, station A contacts station B 100 km away on 145 MHz and receives an S8 report. If both switch t…
- In free space, station A contacts station B 100 km away on 145 MHz and receives an S8 report. If station A red…
- An amateur station transmitting at 100 W gets an S8 report from the other station. Now it reduces power to 25 …
- An amateur station transmitting at 80 W gets an S8 report. Now it drops to 5 W for a QRP experiment. The other…
- Regarding the wave impedance Z of electromagnetic waves, which of the following descriptions is correct? (Choo…
- In electromagnetic-field theory, the statement that intensity is inversely proportional to the square of the d…
- Sometimes you need to compare the actual radiation of different omnidirectional vertical antennas at zero elev…
- A typical amateur-method for measuring antenna gain is shown. A field-strength meter or receiver at a distant,…
- A typical amateur-method for measuring antenna gain is shown. A field-strength meter or receiver at a distant,…
- If classified by propagation form, radio waves are roughly divided into:
- As the name implies, a ground wave is a radio wave that propagates along the ground; its attenuation character…
- Which component of the atmosphere enables radio waves to propagate worldwide?
- The HF-communication terms "silent zone" (skip zone) and "skip distance" mean:
- "Attenuation" and "fading" are both common terms in radio communication. Their meanings are respectively:
- After a radio signal is repeatedly reflected between the ground and the ionosphere, what changes occur? (Choos…
- When observing a short-wave 2FSK data signal such as RTTY with an SDR receiver's spectrum display, we should s…
- Assuming both the receiving and transmitting antennas are half-wave dipoles, in long-distance contacts relying…
- Two amateur stations A and B, 2000 km apart, both use half-wave horizontal dipoles for HF contacts. If one sta…
- The main factors affecting the short-wave propagation characteristics of the ionosphere are: (Choose all that …
- HF enthusiasts mostly know the term "Maximum Usable Frequency (MUF)." Its meaning is: (Choose all that apply.)
- If the Maximum Usable Frequency (MUF) is known to be 20 MHz, the amateur band with the highest success rate fo…
- If arranged from highest to lowest altitude above the Earth's surface, the ionospheric layers that mainly affe…
- If arranged from highest to lowest electron (ion) density, the ionospheric layers that mainly affect short-wav…
- The influence of the ionosphere on short-wave propagation is mainly reflected in: (Choose all that apply.)
- When discussing DX communication on low short-wave bands such as 1.9 MHz or 3.5 MHz, amateur operators often m…
- Amateur operators often use the "gray line" to establish DX contacts on low short-wave bands such as 1.9 MHz o…
- If you try to contact a certain amateur station via the "long path," your directional antenna should point:
- The parameters necessary for short-wave ionospheric propagation prediction are: (Choose all that apply.)
- When attempting a propagation prediction, the minimum value of the solar flux can be taken as about 50. Its ma…
- Common indicators of geomagnetic activity are the A-index and the K-index. The range of the K-index is:
- The average period of sunspot activity is about:
- The strength of sunspot activity is described by the "sunspot number (SSN)." The general rule is:
- A solar flare can trigger a Sudden Ionospheric Disturbance (SID). Its effect on short-wave communication is:
- Amateur operators often use a parameter abbreviated F107 when predicting HF propagation. Its meaning is:
- Amateur operators often use the parameter abbreviated F107 when predicting HF propagation; its value is genera…
- China's Radio Frequency Allocation Regulations (《无线电频率划分规定》) state that the 122.25–123 GHz amateur band is all…
- Among the following bands, the one most severely affected by rainfall is:
- According to ITU recommendations, vegetation absorbs radio waves to some extent. The general rule is:
Transmitters and Modulation发射机与调制 · 72 questions
- When testing a self-made amateur radio transmitting device, before it passes inspection by a radio testing org…
- In a radio transmitter, the role of the modulator is:
- The main factors that ensure good receiving capability of an amateur radio communication receiver are: (Choose…
- The role of a receiver's demodulator is:
- The main factor to consider when selecting a demodulator is:
- In the sub-audible tone squelch system (CTCSS), roughly what range within the audio band do the tones occupy?
- For a more refined receiver, its specification sheet often lists a "passband rectangular coefficient" or "pass…
- According to the technical specifications, two amateur radio receivers have different "passband rectangular co…
- The main role of a receiver preamplifier is:
- During FM voice communication, can we accurately judge how strong the other station's signal is solely from ho…
- The effect of receiving a WFM signal with a handheld transceiver set to NFM mode is:
- The effect of receiving an NFM signal with a handheld transceiver set to WFM mode is:
- When there is no signal, an FM receiver outputs a strong "shhh" noise. Regarding this noise, the correct descr…
- Which of the following circuits can demodulate an FM signal?
- What is "discrimination" (frequency discrimination, 鉴频)?
- Which of the following can demodulate an AM signal?
- What is "detection" (检波)?
- Regarding the AGC function of a transceiver, the correct statements are: (Choose all that apply.)
- When studying modern communication technology or building amateur radio projects, we often encounter a "DC rec…
- What is the role of the mixer commonly found in receivers and transmitters?
- In a superheterodyne transceiver, the mixer's operation can be divided into "up-conversion" and "down-conversi…
- Superheterodyne amateur transceivers often have a control on the panel for selecting the IF filter bandwidth. …
- In a superheterodyne amateur transceiver, the component responsible for suppressing image-frequency interferen…
- In a superheterodyne receiver the received signal frequency is lower (or higher) than the local-oscillator fre…
- In a superheterodyne receiver the received signal frequency is lower (or higher) than the local-oscillator fre…
- In a superheterodyne receiver the received signal frequency is lower (or higher) than the local-oscillator fre…
- In a superheterodyne receiver the received signal frequency is lower (or higher) than the local-oscillator fre…
- The efficiency of an amateur radio transmitter means:
- The efficiency of an amateur radio transmitter is always significantly below 1. The lost portion of energy:
- If an amateur radio station operates at a DC voltage of 13.8 V, with an FM RF output power of N watts and a po…
- If an amateur radio station operates at an AC voltage of 220 V, with an FM RF output power of N watts and a po…
- If an amateur radio station transmits FM at an RF output power of N watts with a power-supply efficiency of ab…
- The average power supplied to the antenna feeder by a radio transmitter over one RF cycle under no-modulation …
- If a voice transmitter has the same peak output power under different modulation modes, then with no voice inp…
- Which of the following technical indicators describes a receiver's ability to reject adjacent-frequency interf…
- A receiver's ability to reject interference signals near its operating frequency can be expressed by selectivi…
- The flatness of a receiver's frequency response when receiving SSB voice signals can be expressed by selectivi…
- A receiver's ability to reject strong interference signals far from its operating frequency can be expressed b…
- A receiver's ability to reject strong interference signals at a frequency twice the IF away from its operating…
- What is the significance of the magnitude of a receiver's sensitivity indicator?
- What is the significance of expressing a receiver's sensitivity in terms of power level, and what are the comm…
- What is the significance of expressing a receiver's sensitivity in terms of voltage level, and what are the co…
- Most amateur radio receivers have a signal-strength indication function. In the VHF/UHF bands, the minimum sca…
- Two models of amateur transceivers, A and B, give receiver sensitivity indicators of 0.1 μV and 0.15 μV respec…
- When the output signal meets the specified quality standard, the minimum input-signal voltage measured at the …
- When the output signal meets the specified quality standard, the minimum input-signal voltage measured at the …
- When the output signal meets the specified quality standard, the minimum input-signal voltage measured at the …
- When the output signal meets the specified quality standard, the minimum input-signal voltage measured at the …
- When the output signal meets the specified quality standard, the minimum input-signal voltage measured at the …
- When the output signal meets the specified quality standard, the minimum input-signal voltage measured at the …
- Given a receiver whose antenna input impedance is 50 Ω and whose sensitivity specification is 2 μV, the corres…
- Given a receiver whose antenna input impedance is 50 Ω and whose sensitivity specification is 1 μV, the corres…
- The main factor limiting the sensitivity of a modern radio receiver is:
- The term "signal-to-noise ratio (SNR)" is widely used in amateur radio. It refers to:
- For amateur communication that must receive very weak signals, such as EME contacts, the receiver noise figure…
- The squelch sensitivity of a receiver is:
- For amateur communication that must receive very weak signals, such as EME contacts, the receiver noise figure…
- For amateur communication that must receive very weak signals, such as EME contacts, the receiver noise figure…
- For amateur communication that must receive very weak signals, such as EME contacts, the receiver noise figure…
- In radio communication, the "noise temperature" indicator is often used to describe the internal-noise magnitu…
- For an ideal amplifier or receiver that produces no internal noise, the noise figure Fn, noise figure NF, and …
- Suppose an antenna amplifier used for the amateur-satellite service operates at standard temperature (17 °C), …
- The necessary bandwidth is: for a given emission class, the bandwidth just sufficient to ensure the required q…
- For Morse-code (CW) communication at a speed of 25 WPM, accounting for propagation fading and similar factors,…
- For RTTY communication using single sideband, at a speed of 50 baud with a frequency shift of 170 Hz, the nece…
- For single-sideband voice communication that intermittently also transmits RTTY messages at 50 baud with a 70 …
- For ordinary frequency-modulation (FM) voice communication, the necessary bandwidth is approximately:
- A commercial amateur single-sideband transceiver has a voice channel of 300–3000 Hz, with the high audio frequ…
- Modern transceivers are mostly designed and built on DSP technology. Because their main functions are implemen…
- Most SDR transceivers provide a band spectrum display; its basic uses are: (Choose all that apply.)
- Some SDR transceivers can provide encoding/decoding functions for signals such as CW, RTTY, or FT8. This is be…
- Compared with analog transceivers, why can most SDR transceivers provide more flexible filtering?
Radio Direction Finding (ARDF)无线电测向 · 17 questions
- Which of the following activities is suitable for amateur radio operators to organize as competitions or to us…
- Which of the following items, combined with a receiver, can be used for ARDF activities?
- The hidden transmitters used in amateur radio direction-finding activities belong to which category of equipme…
- The IARU (International Amateur Radio Union) rules for amateur radio direction-finding championships require t…
- The receiving antenna of an 80 m-band amateur direction-finder is mostly a combination of a loop antenna and a…
- Sometimes, the shielded loop antenna used in 160/80 m-band amateur direction-finders is replaced by a ferrite-…
- Sometimes a 2 m-band ARDF receiver is optionally fitted with a Yagi antenna having only two elements (a driven…
- Sometimes amateur operators build a 2 m-band ARDF receiver using an HB9CV antenna. Which of the following stat…
- In the data-communication segment of HF amateur bands, we sometimes hear on SSB a signal consisting of two ton…
- In the data-communication segment of HF amateur bands, we sometimes hear on SSB a signal whose tone stays cons…
- In HF amateur bands, we sometimes hear on SSB a signal whose tone varies periodically, and within each period …
- The spectrum of a CW signal appears as:
- The spectrum of an RTTY signal appears as:
- The spectrum of an SSB voice signal appears as:
- The spectrum of an AM voice signal appears as:
- The spectrum of an FM voice signal appears as:
- The spectrum of a PSK31 signal appears as:
Amateur Radio Satellites业余无线电卫星 · 8 questions
- In the amateur radio field, the abbreviation AMSAT refers to:
- When describing amateur radio satellites, the abbreviation OSCAR (奥斯卡) is often used. The origin of this name …
- The launch year, name, international OSCAR number, and transponder mode of China's first amateur satellite are…
- The best time to conduct EME (Earth-Moon-Earth / moonbounce) communication experiments is:
- When installing a preamplifier for occasions requiring reception of extremely weak signals, such as EME commun…
- For communication scenarios needing reception of VHF/UHF weak signals, such as moonbounce experiments, amateur…
- Which of the following amateur bands is most suitable for meteor-scatter communication?
- Which of the following communication modes can be used for meteor-scatter and tropospheric-scatter communicati…
Conductors and Current导体与电流 · 64 questions
- Electrostatic discharge (ESD) is a common electromagnetic phenomenon that accompanies daily life at all times.…
- If a conductor is placed in an electrostatic field, the conductor will exhibit the following characteristics: …
- Direct current (DC) is defined by the direction of charge motion never changing. Which of the following descri…
- Alternating current (AC) is defined by the direction of charge motion alternating with time. Which of the foll…
- Which of the following terms can be used to describe the number of times per second that alternating current c…
- What is the relationship between the "wavelength" frequently mentioned by amateur radio operators and the freq…
- The physical quantity "electromotive force (EMF)" describes:
- The physical quantity "voltage" describes:
- The peak value of a sinusoidal AC voltage or current refers to: ("x＾m" means "x to the power m")
- The peak-to-peak value of a sinusoidal AC voltage or current refers to:
- The RMS (root-mean-square) voltage of any AC voltage refers to: ("x＾m" means "x to the power m")
- The physical quantity "current" describes:
- The physical quantity "resistance" describes:
- The physical quantity "power" describes:
- Ohm's law for DC circuits states: (Choose all that apply.)
- The kinds of current that are not impeded by resistance in a circuit are:
- The term "impedance" describes:
- The unit of electromotive force is:
- The unit of voltage is:
- The unit of current is:
- The unit of resistance is:
- The unit of impedance is:
- The unit of power is:
- The unit of frequency is:
- In the legal system of units, the prefix k has the following mathematical meaning and verbal meaning respectiv…
- In the legal system of units, the prefix m has the following mathematical meaning and verbal meaning respectiv…
- In the system of legal units of measurement, what are the mathematical significance and textual meaning of the…
- In the system of legal units of measurement, what are the mathematical significance and textual meaning of the…
- In the system of legal units of measurement, what are the mathematical significance and textual meaning of the…
- In the system of legal units of measurement, what are the mathematical significance and textual meaning of the…
- In the system of legal units of measurement, what are the mathematical significance and textual meaning of the…
- In the system of legal units of measurement, what are the mathematical significance and textual meaning of the…
- Which of the following amateur radio abbreviations can express the term "radio frequency" or specifically refe…
- The term "audio frequency" (音频) refers to the frequency of sounds that people can generally hear. Which of the…
- The commonly used nominal impedances of the transmission interfaces for radio communication and related test e…
- 1,805,000 Hz can be expressed as:
- 2430 MHz can be expressed as:
- A resistor of 1 ohm resistance is connected in parallel with a 13.8-volt power source; the power dissipated by…
- 5 W can be expressed as:
- 0.25 W can be expressed as:
- 0.4 kW can be expressed as:
- A power source is a kind of power-supply device commonly used by amateur radio operators. Our understanding of…
- The direction of the electromotive force (EMF, 电动势) across the two terminals of a power source is:
- The direction of the voltage across the two terminals of a power source is:
- External power sources for supplying amateur radio equipment come in several types. Common ones include: (Choo…
- Which of the following batteries can be recharged? (Choose all that apply.)
- How can a 12-volt lead-acid battery be charged when the mains power is out?
- When using a storage battery to power a radio station, how should the battery operating time be estimated?
- The effect of a power source's internal resistance on a circuit is:
- Some transceivers have a fuse in series in the 13.8 V DC supply line, followed by a diode of very high rated c…
- Some transceivers have a reset button marked with a number near the 13.8 V DC power socket. What is its functi…
- Which physical quantities can a multimeter be used to measure?
- For a simple sinusoidal AC voltage measured with a multimeter's AC voltage range, the reading is the ___ of th…
- For a simple sinusoidal AC voltage measured with a multimeter's DC voltage range, the reading should be regard…
- When using a multimeter to measure current, how should the meter be connected into the circuit?
- Which of the following practices may damage a multimeter?
- When measuring the resistance between two points of a circuit with a multimeter's resistance range, what preco…
- A method that can be used to roughly judge whether a dry-cell battery has failed is:
- Using a multimeter's resistance range to measure a quarter-wavelength grounded antenna with an impedance of 50…
- Using a multimeter's resistance range to measure a quarter-wavelength grounded antenna with an impedance of 50…
- Using a multimeter's resistance range to measure the center-feed-point impedance of a home-built quarter-wavel…
- Using a multimeter's resistance range to measure the resistance between the center conductor and the shield of…
- Using a multimeter's resistance range to measure the resistance between the center conductor and the shield of…
- Which soldering material is relatively suitable for amateur radio construction and repair?
Ohm's Law and Resistance欧姆定律与电阻 · 67 questions
- Connect a load of resistance R to a source of voltage U. Regarding the current I in the load and the power P c…
- A current I flows through a load of resistance R. Regarding the voltage U across the load and the power P cons…
- A resistive load has voltage U across it and current I flowing through it. Regarding the load's resistance R a…
- A resistive load has voltage U across it and consumes power P. Regarding the load's resistance R and the curre…
- Two loads have resistances R1 and R2. R1's resistance is N times R2's. After connecting them in parallel to a …
- Two loads have resistances R1 and R2. R1's resistance is N times R2's. After connecting them in series to a so…
- Given that devices A and B operate at the same voltage, if A consumes N times the electrical power of B, which…
- Given that devices A and B operate at the same voltage, if the current through A is N times that through B, wh…
- After connecting N identical resistive loads in series to a source, compared with connecting each load separat…
- After connecting N identical resistive loads in parallel to a source, compared with connecting each load separ…
- For a resistive load, if the voltage across it is increased by n%, then: ('x＾m' means 'x to the power m')
- For a resistive load, if the voltage across it is decreased by n%, then: ('x＾m' means 'x to the power m')
- For a sinusoidal AC signal with a peak-to-peak value of 100 V, its RMS voltage is:
- For a sinusoidal AC signal with a peak value of 100 V, its RMS voltage is:
- For a square-wave signal with a minimum of -50 V and a peak-to-peak of 100 V, its RMS voltage is:
- For a square-wave signal with a minimum of 0 V and a peak-to-peak of 100 V, its RMS voltage is:
- For a triangular-wave signal with a minimum of -50 V and a peak-to-peak of 100 V, its RMS voltage is:
- For a triangular-wave signal with a minimum of 0 V and a peak-to-peak of 100 V, its RMS voltage is:
- For a sinusoidal AC signal with a peak-to-peak value of 100 V, its average value is:
- For a sinusoidal AC signal with a peak value of 100 V, its average value is:
- For a square-wave signal with a minimum of -50 V and a peak-to-peak of 100 V, its average value is:
- For a square-wave signal with a minimum of 0 V and a peak-to-peak of 100 V, its average value is:
- For a triangular-wave signal with a minimum of -50 V and a peak-to-peak of 100 V, its average value is:
- For a triangular-wave signal with a minimum of 0 V and a peak-to-peak of 100 V, its average value is:
- Drive two identical resistive loads with a 120 V battery bank and an AC transformer of 120 V peak voltage resp…
- Drive two identical resistive loads with a 120 V battery bank and an AC transformer of 120 V RMS voltage respe…
- Drive two identical resistive loads with a 120 V battery bank and a 120 V RMS AC transformer with a series dio…
- Drive two identical resistive loads with a 120 V battery bank and a 120 V peak AC transformer through a capaci…
- Drive two identical resistive loads with a 120 V RMS, 50 Hz AC source and a 120 V RMS, 10 kHz square-wave sour…
- The component capable of storing energy in the form of an electric field is:
- If a sinusoidal AC voltage is applied across a capacitor, the magnitude of the current flowing through the cap…
- For a capacitor whose capacitive reactance is measured as some number of ohms at a certain frequency, if the f…
- The component capable of storing energy in the form of a magnetic field is:
- If a sinusoidal AC voltage is applied across a coil, the magnitude of the current flowing through the coil:
- For an inductive coil whose inductive reactance is measured as some ohms at a certain frequency, if the freque…
- The term "phase difference" is typically used to describe the lead or lag relationship in time between two per…
- Connecting two sinusoidal voltage sources of equal amplitude and with a phase difference of 360° in series yie…
- Connecting two sinusoidal voltage sources of equal amplitude and with a phase difference of 180° in series yie…
- Connecting two sinusoidal voltage sources of equal amplitude and with a phase difference of 90° in series yiel…
- When a sinusoidal AC voltage is applied across a capacitor, the current through it is a sinusoidal AC current.…
- If a sinusoidal AC current flows through a capacitor, the voltage across it is a sinusoidal AC voltage. The ph…
- When a sinusoidal AC voltage is applied across a coil, the current through it is a sinusoidal AC current. The …
- If a sinusoidal AC current flows through a coil, the voltage across it is a sinusoidal AC voltage. The phase o…
- An R–C series circuit is suddenly connected to a DC voltage U; the voltage across capacitor C will:
- Given a resistor R and capacitor C, the product of the resistance and capacitance is called the time constant …
- When an R–C series circuit is suddenly connected to a DC voltage U, the voltage across resistor R will:
- Given a resistor R and capacitor C, the product RC is the time constant τ. When connected in series and sudden…
- When an R–C series circuit is suddenly connected to DC voltage U, the current through resistor R will:
- When an R–C series circuit is suddenly connected to DC voltage U, the current through capacitor C will:
- An R–C parallel circuit is connected to a DC supply of voltage U. When the supply is suddenly disconnected, th…
- An R–C parallel circuit is connected to a DC supply of voltage U. When the supply is suddenly disconnected, th…
- An R–C parallel circuit is connected to a DC supply of voltage U. When the supply is suddenly disconnected, th…
- An R–C parallel circuit is connected to a DC supply of voltage U. When the supply is suddenly disconnected, th…
- An R–L series circuit is suddenly connected to a DC voltage U; the voltage across inductor L will:
- Given a resistor R and inductor L, the product of the resistance and inductance is the time constant τ. When R…
- Given a resistor R and inductor L, the product RL is the time constant τ. When connected in series and suddenl…
- When an R–L series circuit is suddenly connected to a DC voltage U, the voltage across resistor R will:
- When an R–L series circuit is suddenly connected to a DC voltage U, the current through resistor R will:
- When an R–L series circuit is suddenly connected to a DC voltage U, the current through inductor L will:
- An R–L parallel circuit is placed in a DC circuit of current I. When the circuit is suddenly opened, the volta…
- A series or parallel circuit of a capacitor and an inductor has a state in which, at a particular frequency, t…
- The resonant frequency f of an LC resonant circuit made of a coil of inductance L and a capacitor of capacitan…
- The total impedance of a series circuit consisting of a coil of inductance L and a capacitor of capacitance C …
- The total impedance of a parallel circuit consisting of a coil of inductance L and a capacitor of capacitance …
- The Q value of a resonant circuit we usually discuss refers to the "loaded Q" after the circuit is connected t…
- From the magnitude of the Q of a resonant circuit or a resonant antenna circuit we can conclude:
- The bandwidth (BW) of a resonant circuit is:
Circuit Components and Symbols电路元件与符号 · 77 questions
- The circuit-component symbol in the accompanying figure represents:
- By manufacturing material, common resistors include: (Choose all that apply.)
- Among components used in assembling an amateur transceiver, the one that is usually marked with a rated dissip…
- A resistor's "rated power" means:
- Surface-mount devices (SMDs) are widely used in amateur radio projects. The size codes 0402, 0603, 0805, 1206 …
- A resistor's color bands are, in order, brown, orange, orange, black. Its resistance is:
- A resistor's color bands are, in order, yellow, white, red, silver. Its resistance is:
- A resistor's color bands are, in order, silver, black, orange, orange, brown. Its resistance is:
- A chip resistor is marked "2R7". Its resistance is:
- A chip resistor is marked "3802". Its resistance is:
- When building circuits with higher operating voltages, one should pay attention to component voltage ratings t…
- A potentiometer is a three-terminal resistive element whose contact end slides on the resistive body. It can b…
- Which of the following components can be used to implement volume adjustment?
- A capacitor is formed by two electrodes insulated from each other. If subdivided by manufacturing material, co…
- The monolithic capacitor (独石电容) that we often use is a:
- Among the components used in assembling amateur transceivers, those typically marked with a rated voltage-with…
- When building homemade circuit projects, hobbyists often replace electrolytic capacitors of about 1–100 µF wit…
- In a circuit diagram, if the capacitance value of an electrolytic capacitor is not marked with a unit, the def…
- In a circuit diagram, if the capacitance of a non-electrolytic capacitor is marked with an integer or decimal …
- If you see a non-electrolytic capacitor's value marked with a 3-digit code on a circuit diagram or the actual …
- If you see a resistance value marked with a 3-digit code on a circuit diagram or the actual component, it shou…
- If you see a resistance marked with 2–3 digits and a letter (e.g., 8R2, 2K7, 1M5) on a diagram or component, i…
- In a circuit diagram, if the capacitance of a non-electrolytic capacitor is marked with a decimal less than 1,…
- In amateur transceivers, the component used to block DC or to provide a bypass for AC signals is:
- When building homemade projects, hobbyists often place a large capacitor in parallel with one or more small ca…
- Suppose a 1000 µF capacitor is connected across a circuit. Which of the following would NOT seriously disturb …
- Which of the following components are made from a coil (wire winding)? (Choose all that apply.)
- Inductors come in many types. Those commonly used in RF circuits include: (Choose all that apply.)
- The quality factor Q of an inductor is the ratio of its inductance to its loss resistance. Which of the follow…
- A magnetic-core inductor made with a suitable magnetic material has lower loss than an air-core inductor of th…
- Suppose a 100 µH coil is connected across a circuit. Which of the following would NOT seriously disturb the ci…
- Xiao Ming used a 4.2 V low-voltage battery and several passive components for a circuit experiment. While conn…
- A switch is an electronic part that controls a circuit using on/off states. The following can be used as switc…
- The single-pole double-throw (SPDT) switch is a commonly used switching element. What does "single-pole double…
- Which of the following components can protect other components in a circuit from overcurrent surges?
- Among the components used in assembling amateur transceivers, those typically marked with a rated current are:…
- In amateur projects, fuses are often glass- or ceramic-bodied fuse cartridges used to enhance circuit safety. …
- A relay is a switch with electrical isolation, often used to control high-power or high-voltage circuits with …
- If a switching device is used to control whether a relay's armature coil is energized — for example, with the …
- If a switching device controls whether a relay's armature coil is energized, a small capacitor or a reverse-bi…
- If a relay controls a DC load, we sometimes connect a small capacitor across the relay's contacts. Its purpose…
- Electromagnetic induction is the phenomenon where a conductor placed in a changing magnetic field develops an …
- The electromagnetic term "mutual inductance" (互感现象) means:
- Why is a transformer's iron core built from many insulated silicon-steel laminations of large cross-section an…
- For an ideal transformer, the turns ratio of primary to secondary determines the voltage ratio. Suppose an ide…
- For an ideal transformer, the turns ratio determines the voltage ratio. Suppose an ideal transformer has 120 p…
- In RF circuits, one use of a transformer is impedance transformation. A certain HF transformer wound on a ferr…
- If an antenna has an impedance of 450 Ω, what turns ratio transformer is needed to transform it to 50 Ω?
- A transmission-line transformer is an RF transformer designed using transmission-line theory and is widely use…
- Using a solid wire as a connection in an RF circuit at frequencies of tens of megahertz produces which phenome…
- For solid copper wire and a hollow copper tube of the same material, diameter, and length, how do their heat l…
- A capacitor measures a capacitive reactance of 100 Ω at 50 Hz. One would infer its reactance at 5 MHz should b…
- An inductor coil measures an inductive reactance of 10 Ω at 50 Hz. One would infer its reactance at 5 MHz shou…
- Which of the following are active devices? (Choose all that apply.)
- Which of the following components allows current to flow in only one direction?
- What are the two electrodes of a diode called?
- How can you identify the cathode (negative terminal) of a semiconductor diode by its appearance?
- What device does the abbreviation LED stand for?
- Among the following devices, which can be used as an indicator lamp?
- What must be observed when connecting an LED to a DC supply?
- Which of the following components can convert alternating current into pulsating direct current?
- The forward conduction voltage drop of a silicon rectifier diode is approximately:
- When reading a circuit diagram or running a circuit simulation, if you see the symbol "BJT", it denotes:
- The three basic electrodes of a field-effect transistor are:
- The three basic electrodes of a bipolar junction transistor are:
- The three basic electrodes of a vacuum triode are:
- What is the minimum number of pins a vacuum triode must have?
- The most commonly used parameter, unit, and symbol describing the amplification ability of a field-effect tran…
- The most commonly used parameter, unit, and symbol describing the amplification capability of a bipolar transi…
- The most commonly used parameter, unit, and symbol describing the amplification capability of an electronic tr…
- If the control electrodes of devices are arranged in order of increasing input impedance, they could be:
- Which of the following components can be used to achieve the function of controlling a larger current with a s…
- Which of the following components can be used both as an electronic switch and as an amplifier?
- An integrated circuit refers to:
- The basic concept of an ideal operational amplifier is: (Choose all that apply.)
- What type of integrated circuit does an integrated operational amplifier belong to?
- Some integrated circuits commonly seen in amateur radio projects, such as operational amplifiers and microproc…
Transistor Amplifier Circuits晶体管放大电路 · 106 questions
- The circuit shown in the figure is:
- In the transistor amplifier circuit below, the common name and function of Rc is:
- In the transistor amplifier circuit below, the common name and function of Re is:
- In the transistor amplifier circuit below, the common name and function of Rb1 is:
- In the transistor amplifier circuit below, the common name and function of Cb is:
- In the transistor amplifier circuit below, the common name and function of Ce is:
- In the transistor amplifier circuit below, the common name and function of Cc is:
- The function of the following circuit is:
- The following circuit is a:
- A metal-oxide semiconductor field-effect transistor (MOSFET) is often used in circuits that have only two stat…
- Regarding the amplification of a field-effect transistor amplifier, which of the following statements is corre…
- Regarding the amplification of a bipolar-junction transistor amplifier, which of the following statements is c…
- For bipolar-junction transistor amplifiers, ordered from lowest to highest input impedance:
- For bipolar-junction transistor amplifiers, ordered from lowest to highest current gain:
- For bipolar-junction transistor amplifiers, ordered from lowest to highest voltage gain:
- For bipolar-junction transistor amplifiers, ordered from lowest to highest output impedance:
- In a bipolar-junction transistor amplifier circuit, the configuration commonly called an emitter follower is:
- Which of the following statements about the amplification of a triode (electron-tube) amplifier is correct? (C…
- A small-signal amplifier is:
- A large-signal amplifier is:
- Among the following amplifiers, the one with the lowest power-supply efficiency is:
- Among the following amplifiers, the one with the highest power-supply efficiency is:
- Among the following amplifiers, the one with the smallest waveform distortion is:
- Among the following amplifiers, the one with the largest waveform distortion is:
- Among the following amplifiers, the one suitable for use as an audio power amplifier is:
- Among the following amplifiers, the one suitable for use as an audio small-signal amplifier is:
- Among the following amplifiers, those suitable for use as a CW RF power amplifier are: (Choose all that apply.…
- Among the following amplifiers, those suitable for use as an FM RF power amplifier are: (Choose all that apply…
- Among the following amplifier circuits, those suitable for use as an SSB RF power amplifier are: (Choose all t…
- Amateur radio operators often divide amplifiers into Classes A, B, C, D, etc., which in circuit theory corresp…
- Some of the Classes A, B, C, D amplifiers can linearly amplify an audio signal. The correct descriptions are: …
- All of the Classes A, B, C, D amplifiers can be used to amplify RF signals. Regarding this conclusion, the cor…
- Amateur radio operators often use Class AB amplifiers as RF power amplifiers. Their characteristics are: (Choo…
- Although a single-ended Class B or Class AB amplifier has waveform distortion, generates harmonics, and even h…
- If the output-waveform distortion of Classes A, B, C, D amplifiers is arranged from smallest to largest, the c…
- If Classes A, B, C, D amplifiers are used as RF power amplifiers, arranged from highest to lowest power-supply…
- Why do Class B or Class AB audio amplifiers need push-pull operation, while a linear RF amplifier of the same …
- Among Classes A, B, C, D, which class can serve as a single-transistor linear power amplifier for a 10 kHz to …
- Among Classes A, B, C, D, which classes can all serve as the FM RF power amplifier of a handheld transceiver? …
- Among Classes A, B, C, D, which classes can all serve as a CW RF power amplifier? (Power-supply efficiency not…
- Among Classes A, B, C, D, the one suited to a small-signal amplifier is:
- Among Classes A, B, C, D, all the classes that belong to large-signal amplifiers are:
- Many amateur radio audio power amplifiers use two series-connected output power transistors, each handling the…
- HF-band vacuum-tube linear amplifiers mostly use the common-grid circuit configuration. The advantages of this…
- Sometimes amateur radio operators use two power transistors in parallel to build the final or driver stage of …
- Negative feedback in an amplifier refers to a circuit that:
- Amateur radio equipment makes extensive use of negative-feedback techniques in amplifier design. The character…
- From the viewpoint of energy conversion, "matching" between a circuit and its load means: (Choose all that app…
- When a signal source with constant internal resistance is impedance-"matched" to its load, the power dissipate…
- A circuit's "nonlinear distortion" means that, compared with the input signal, its output signal undergoes the…
- An active device can transform a single-frequency input into a complex periodic signal whose waveform deviates…
- What is the spectral difference between a sinusoidal or cosine signal of frequency f and a complex periodic si…
- The spectral characteristic of a single infinitely narrow pulse is:
- A signal that contains only one frequency component is:
- A signal that has uniformly distributed continuous frequency components across the entire spectrum is:
- While an amateur station was transmitting an SSB voice signal, a pair of headphones connected to a certain cir…
- While an amateur station was transmitting CW (continuous wave), a pair of headphones connected to a certain ci…
- The hobbyist Xiao-qiang was experimenting with a circuit. When powered on, a nearby receiver picked up a bird-…
- Two signals of frequencies f1 and f2 passing through the same nonlinear element intermodulate with each other;…
- The term "beat" (差拍) refers to a phenomenon: (Choose all that apply.)
- Amateur radio operators often use a frequency multiplier to obtain an output at an integer multiple of the inp…
- Through which of the following circuits does a sinusoidal AC signal generate higher-order harmonics? (Choose a…
- Among the following modulation modes, those in which the modulated signal's amplitude remains constant are: (C…
- Among the following modulation modes, those in which applying a modulating signal of a specific frequency and …
- Among the following modulation modes, those in which applying a modulating signal of a specific frequency and …
- Among the following modulation modes, the one in which the modulated signal's carrier phase remains constant i…
- Among the following modulation modes, the one in which the modulated signal's carrier amplitude remains consta…
- Among the following modulation modes, the one whose modulated signal contains only a single set of sidebands c…
- A diode ring modulator can be used to build a product detector. The function of this detector is:
- A diode ring modulator can be used to build the mixer of a superheterodyne receiver. The function of this mixe…
- A diode ring modulator can be used to build the mixer of a heterodyne transmitter. The function of this mixer …
- A diode ring modulator can be used to generate a double-sideband suppressed-carrier AM signal. Its operating p…
- A diode ring modulator can be used to generate ordinary AM (amplitude modulation) signals with an unsuppressed…
- The essential elements for constituting an oscillator are:
- Inserting a wire at the SSB (single sideband) receiver's antenna port, with the other end placed near a transi…
- The metrological term "ppm" frequently appears in transmitter equipment spec sheets or amateur radio literatur…
- Sometimes we see a function abbreviated VFO on the panel or in the function menu of an amateur transceiver. It…
- Sometimes we see a function or circuit block abbreviated VXO in a homebrew amateur transceiver or its schemati…
- Sometimes we see a circuit abbreviated VCO in amateur radio literature or a device schematic. It stands for:
- Sometimes we see a component abbreviated XTAL in amateur radio literature or a device schematic. It stands for…
- To improve the frequency stability of radio equipment, various high-Q (quality factor) piezoelectric resonator…
- Regarding TCXO or OCXO mentioned in the manuals of high-end radio communication equipment, the following descr…
- Although nonlinear distortion in a circuit mainly comes from active devices, the inductors or transformers in …
- A circuit's "phase distortion" means the output signal, compared with the input, undergoes the following chang…
- A circuit's "frequency distortion" means the output signal waveform, compared with the input, undergoes the fo…
- When assembling an amateur transceiver, hams often use resonant circuits (tank circuits) to select signals of …
- Building a frequency multiplier uses a high-performance band-pass filter or some LC resonant circuit with exce…
- The "cutoff frequency" of a low-pass filter refers to:
- The "3 dB bandwidth" of a band-pass filter refers to:
- A filter has a parameter called "passband ripple." It refers to:
- When describing a receiver's band-preselection filter and a transmitter's output filter, some technical docume…
- Suppose an amateur repeater's receiver and transmitter share one antenna, with uplink and downlink frequencies…
- To prevent the RF energy emitted by an HF amateur station from interfering with a telephone placed near the an…
- If the normal transmission of an HF amateur station interferes with a VHF television near the antenna, a possi…
- If 50 Hz AC passes through a full-wave rectifier and is applied to a resistive load, what is the waveform acro…
- In a rectifier-filter circuit, the role of the bleed resistor is:
- When building a switching power supply, a relay-driving circuit, or even an indicator-lamp-driving circuit, we…
- In the power supply for an amateur transceiver, a switching power supply can be more compact and lightweight t…
- The general working process of a communication switching power supply that converts 220 V AC input to 13.8 V D…
- Sometimes a local oscillator (LO) using a PLL (phase-locked loop) frequency synthesizer adds phase noise to th…
- Many amateur transceivers use a direct digital frequency synthesizer (DDS) in their local-oscillator circuit. …
- A resistor is a passive component, so why does it also produce noise?
- The noise of active devices mainly includes: (Choose all that apply.)
- Why do an overly long coaxial cable, or a coaxial cable with too high a VSWR (standing-wave ratio), add noise …
- Why does the atmosphere also have noise?
- A poor-quality switching power supply adds electromagnetic noise to a radio receiver. The main source is:
Digital Logic Gates数字逻辑门 · 22 questions
- The two-input AND gate is one of the simplest digital logic circuits. If the two inputs are respectively 00, 0…
- The two-input OR gate is one of the simplest digital logic circuits. If the two inputs are respectively 00, 01…
- The two-input XOR (exclusive-OR) gate is one of the simplest digital logic circuits. If the two inputs are res…
- The two-input NAND (NOT-AND) gate is one of the simplest digital logic circuits. If the two inputs are respect…
- The two-input NOR (NOT-OR) gate is one of the simplest digital logic circuits. If the two inputs are respectiv…
- The two-input XNOR (exclusive-NOR / equivalence) gate is one of the simplest digital logic circuits. If the tw…
- A D flip-flop is a sequential logic circuit with data input D, clock input CK, and data output Q. Suppose the …
- A D flip-flop has data input D, clock input CK, and data output Q. If the inverted Q is fed back to D, what ha…
- When building SDR (software-defined radio) projects, especially direct-RF-sampling digital transceivers, we us…
- The first step of digital signal processing (DSP) is converting the analog signal to a digital signal. To ensu…
- The first step of digital signal processing (DSP) is converting the analog signal to a digital signal. The qua…
- During digital-to-analog conversion, to correctly reconstruct the analog signal the DAC's sample rate should b…
- Convert an analog signal of frequency f and maximum voltage U into a digital signal. If the digital signal mus…
- When writing SDR software, hams often use an I/Q sequence centered at 0 Hz, using both positive and negative f…
- In an SDR transceiver, the main functions are all implemented by digital signal-processing algorithms, includi…
- Since analog filters already support amateur radio communication successfully, why do we still develop and use…
- In an SDR system, mixing (frequency translation) of I/Q signals can be done using the algorithm:
- In an SDR system, demodulating an AM complex signal can be done using the algorithm:
- Digital filters in an SDR system come in several types. The common ones are: (Choose all that apply.)
- When building an SDR transmitter, the algorithms that can generate an SSB (single sideband) signal are: (Choos…
- In an SDR system, the fast Fourier transform (FFT) can be used to: (Choose all that apply.)
- When using an SDR transceiver, we often see window-function options related to the spectrum display in the sys…
Measurement and Instruments测量与仪表 · 47 questions
- A multimeter's DC voltage range is used to measure a bipolar symmetric square-wave voltage (duty cycle 1:1). T…
- If a moving-coil (magneto-electric) multimeter's AC voltage range is used to measure a bipolar symmetric squar…
- Using an analog (pointer) multimeter's DC voltage range to measure a square-wave voltage whose minimum value i…
- A multimeter's resistance range is used to measure a circuit. At first the meter indicates a very small resist…
- To check whether an electrolytic capacitor is sound, one should use: (Choose all that apply.)
- Using an analog multimeter's resistance range to measure a common component, the first time the test leads are…
- An analog multimeter's voltage range has an "ohms-per-volt" (ohms per volt) specification. A larger ohms-per-v…
- Using a digital multimeter's DC voltage range to measure the voltage of a constant-amplitude audio signal betw…
- Among the following charts, the one most easily used to express and explain the principle of PSK modulation is…
- Among the following charts, the one most easily used to express and explain the principle of analog FM modulat…
- Among the following charts, the one most easily used to express and explain the principle of SSB modulation is…
- Among the following charts, the one most easily used to express and explain the principle of RTTY modulation i…
- Among the following charts, the one most easily used to express and explain the principle of SSTV modulation i…
- Among the following charts, the one most easily used to express and explain the difference in operating points…
- Among the following charts, the one most easily used to express and explain the degree of temperature drift of…
- The illustrated circuit is a simple field-strength meter commonly used by amateur radio operators. The functio…
- Using a small dipole antenna about 10 cm per arm in parallel with a crystal diode and a DC microammeter to mak…
- When using a network analyzer or antenna analyzer to measure cables and antennas, calibration standards are re…
- What should you pay attention to when choosing an SWR meter for your FM station?
- If you use an SWR meter to measure the output power of a transmitter, where should you place the meter?
- An amplifier has a signal gain of 20 dB. This means:
- When an RF signal passes through a certain circuit, a loss of 20 dB is produced. This lost energy:
- The output signal power of a circuit is 100 times the input signal power. The gain of this circuit is:
- The output signal power of a circuit is 1,000,000 times the input signal power. The gain of this circuit is:
- The output signal power of a circuit is 5 times the input signal power. The gain of this circuit is approximat…
- The input signal power of a circuit is half the output signal power. The gain of this circuit is approximately…
- The output signal voltage of a circuit is 100 times the input signal voltage. The gain of this circuit is:
- The output signal voltage of a circuit is 10,000 times the input signal voltage. The gain of this circuit is: …
- The output signal voltage of a circuit is 10 times the input signal voltage. The gain of this circuit is appro…
- The input signal voltage of a circuit is half the output signal voltage. The gain of this circuit is approxima…
- The output signal power of a circuit is 1/100 of the input signal power. The gain of this circuit is:
- The output signal power of a circuit is one millionth of the input signal power. The gain of this circuit is:
- The output signal power of a circuit is 1/5 of the input signal power. The gain of this circuit is approximate…
- The output signal power of a circuit is half the input signal power. The gain of this circuit is approximately…
- The output signal voltage of a circuit is 1/100 of the input signal voltage. The gain of this circuit is:
- The output signal voltage of a circuit is one ten-thousandth of the input signal voltage. The gain of this cir…
- The output signal voltage of a circuit is 1/10 of the input signal voltage. The gain of this circuit is approx…
- The output signal voltage of a circuit is half the input signal voltage. The gain of this circuit is approxima…
- If a signal passes in sequence through three circuits with gains of x dB, y dB, and z dB, then the total gain …
- If, after passing through a circuit with a gain of x dB, a signal is split equally into two paths by a power s…
- A receiver's signal-strength meter (S-meter) is graduated 1 to 9 with a 6 dB step per division. A station tran…
- A receiver's signal-strength meter (S-meter) is graduated 1 to 9 with a 6 dB step per division. A station tran…
- An RF signal with a power of 0 dBm passes through a circuit with a gain of 23 dB; the output power is: (Choose…
- An RF signal with a power of 0 dBμ passes through a circuit with a gain of 36 dB; the output power is: (Choose…
- An RF signal with a power of 0 dBW passes through a circuit with a gain of −36 dB; the output power is: (Choos…
- An RF signal with a power of −133 dBm passes through a circuit with a gain of 60 dB; the output power is: (Cho…
- Using an oscilloscope's AC-coupling mode, the measured voltage waveform of an equal-amplitude audio signal in …
Transmitter Technical Specs发射设备技术指标 · 31 questions
- The following indicators of amateur radio transmitting equipment must comply with relevant national regulation…
- The radio transmitting equipment of an amateur station should meet the following principal technical indicator…
- Frequency tolerance (频率容限) means: (Choose all that apply.)
- Frequency tolerance is an important indicator of transmitting equipment, and is usually expressed in the follo…
- Spurious-domain emission power is an important indicator of transmitting equipment, and is usually expressed i…
- Spurious emission (杂散发射) means: (Choose all that apply.)
- The principal technical-indicator requirements that dedicated amateur radio transmitting equipment must satisf…
- Which of the following situations produces damped-wave (减幅波) radiation:
- According to the national standard GB 8702-2014 'Electromagnetic Environment Control Limits' (《电磁环境控制限值》), fro…
- According to the national standard GB 8702-2014 'Electromagnetic Environment Control Limits' (《电磁环境控制限值》), pub…
- Why do the exposure limits in China's 'Electromagnetic Environment Control Limits' (《电磁环境控制限值》) standard diffe…
- Regarding self-made, modified, or assembled radio transmitting equipment, which of the following statements is…
- Do VHF and UHF signals in the air belong to which of the following types of radiation?
- Installing lightning protection for an amateur station is to prevent lightning damage. The main components of …
- The function of lightning-protection grounding is:
- Regarding the grounding of a lightning protection installation, the most basic requirement is:
- For an ordinary building, how large at most can the protection zone of a single lightning rod be:
- Which of the following conductive materials is most suitable for connecting the various grounded components at…
- What should be noted when installing a lightning arrester for a coaxial feed line?
- Which of the following is an effective measure for lightning-protection grounding of an antenna tower?
- Considering that the actual working environment necessarily has some humidity, then according to the limits fo…
- If the contact voltage is the same, how does the safety threat to the human body from touching a bare conducto…
- If you touch with both hands the two endpoints of circuits whose voltage effective values are the same but who…
- If it is unavoidable and you must repair live radio equipment powered by the mains, you should:
- A live equipment chassis can endanger personal safety. The relevant preventive measures include: (Choose all t…
- Even after the equipment's power cord has been unplugged, what safety risk may still be encountered during rep…
- For self-made equipment powered by 220 V AC mains, the safety measures should at least include:
- How can you ensure a self-made amateur radio project has high electrical safety? (Choose all that apply.)
- What potential risk exists when using an ordinary 12 V lead-acid battery to power the station?
- If a lead-acid battery is charged or discharged too fast, what risk arises?
- If electrical equipment, cables, or a power device catches fire, the correct action is:
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