CRAC Bilingual Manual: 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 regulations:

1. Afrequency tolerance and spurious-domain emission power
2. Bfrequency-modulation deviation and modulation index
3. Cfrequency tolerance and out-of-band emission
4. Dallotted frequency band and necessary bandwidth

The radio transmitting equipment of an amateur station should meet the following principal technical indicators prescribed by the state:

1. AIt meets the frequency tolerance and meets the maximum permissible power level of spurious emission
2. BSpurious emission is not lower than the maximum permissible power level, the supply voltage and frequency conform to national grid standards, and standard antenna impedance is used
3. CSpurious emission is not lower than the maximum permissible power level, frequency drift is not lower than the frequency tolerance, and power-supply efficiency meets energy-saving requirements
4. DThe operating frequency range is wide enough, spurious emission is not lower than the maximum permissible power level, and the bandwidth is greater than the permitted minimum

Frequency tolerance (频率容限) means: (Choose all that apply.)

1. Athe maximum permissible deviation of the center frequency of the band occupied by the emission from the assigned frequency
2. Bthe maximum permissible deviation of the characteristic frequency of the emission from the reference frequency
3. Cthe maximum permissible deviation of the center frequency of the band occupied by the emission from the highest frequency
4. Dthe maximum permissible deviation of the characteristic frequency of the emission from the necessary frequency

Frequency tolerance is an important indicator of transmitting equipment, and is usually expressed in the following units: (Choose all that apply.)

1. Aparts per million (ppm)
2. Bhertz (Hz)
3. Cpercent
4. Dmegahertz (MHz)

Spurious-domain emission power is an important indicator of transmitting equipment, and is usually expressed in the following units: (Choose all that apply.)

1. Aabsolute power in dBm
2. Bdecibels relative to carrier power, dBc
3. Crelative value below PEP transmit power, in dB
4. Dabsolute power (watts)

Spurious emission (杂散发射) means: (Choose all that apply.)

1. Aemission on one or more frequencies outside the necessary bandwidth whose level can be reduced without affecting the transmission of the corresponding information
2. Bspurious emission includes harmonic emissions and parasitic emissions
3. Cspurious emission includes intermodulation products and frequency-conversion products
4. Dspurious emission includes harmonic emissions and out-of-band emissions

The principal technical-indicator requirements that dedicated amateur radio transmitting equipment must satisfy include:

1. Afrequency tolerance and spurious radiation not exceeding the limits, and the transmit frequency not exceeding the amateur service and amateur-satellite service frequencies prescribed by the state
2. Bfrequency tolerance not lower than the limit, spurious radiation not exceeding the limit, and the transmit frequency not exceeding the amateur service and amateur-satellite service frequencies prescribed by the state
3. Cfrequency tolerance and spurious radiation not exceeding the limits, and the transmit frequency including the amateur service and amateur-satellite service frequencies
4. Dtransmit power not lower than the power limit, and output impedance conforms to industrial standards

Which of the following situations produces damped-wave (减幅波) radiation:

1. Asparking at a circuit contact point
2. Bkeying transmission of an intercom/handheld
3. Clocal-oscillator leakage of a television
4. Dleakage from a medical high-frequency heater

According to the national standard GB 8702-2014 ‘Electromagnetic Environment Control Limits’ (《电磁环境控制限值》), from the perspective of electromagnetic-environment protection management, emissions of electromagnetic fields into unshielded space that may be exempted from management include: (Choose all that apply.)

1. Aradio communication facilities (equipment) with frequency range 0.1–3 MHz and equivalent radiated power below 300 W
2. Bradio communication facilities (equipment) with frequency range 3 MHz–300 GHz and equivalent radiated power below 100 W
3. Call amateur stations transmitting below 30 MHz
4. Dall amateur stations transmitting above 30 MHz

According to the national standard GB 8702-2014 ‘Electromagnetic Environment Control Limits’ (《电磁环境控制限值》), public exposure (公众曝露) means:

1. Athe total electric-field, magnetic-field, and electromagnetic-field irradiation received by the public
2. Boccupational exposure
3. Cmedical exposure
4. Dradiation exposure from medical diagnosis or treatment

Why do the exposure limits in China’s ‘Electromagnetic Environment Control Limits’ (《电磁环境控制限值》) standard differ with frequency?

1. AThe human body absorbs certain specific wavelengths of electromagnetic waves more
2. Blower-frequency radio waves do not penetrate the human body
3. Cbecause higher-frequency electromagnetic waves are uncommon in nature
4. Dlower-frequency radio waves have higher energy than higher-frequency ones

Regarding self-made, modified, or assembled radio transmitting equipment, which of the following statements is correct? (Choose all that apply.)

1. ASelf-made, modified, or assembled radio transmitting equipment should comply with the technical requirements listed in ‘Radio Frequency Technical Requirements and Test Methods for Amateur Radio Equipment’ (GB/T 32658-2016)
2. BSelf-made, modified, or assembled radio transmitting equipment should comply with the technical requirements listed in ‘General Specification for Shortwave Single-Sideband Communication Equipment’ (GB/T 16946-2017)
3. CThe radio management authority may carry out relevant technical testing free of charge in accordance with relevant standards
4. DSelf-made, modified, or assembled radio transmitting equipment may be exempt from the supervision and administration of the radio management authority

Do VHF and UHF signals in the air belong to which of the following types of radiation?

1. Anon-ionizing radiation
2. Bionizing radiation
3. Calpha radiation
4. Dgamma radiation

Installing lightning protection for an amateur station is to prevent lightning damage. The main components of a traditional lightning protection installation include:

1. Aair-termination device (lightning rod), down conductor, and grounding electrode
2. Bantenna, circuit breaker, and ground wire
3. Clightning rod, neon lamp, and self-resetting fuse
4. Dlightning rod, zinc-oxide overvoltage protector, and circuit breaker

The function of lightning-protection grounding is:

1. Ato effectively dissipate the lightning current introduced by the air-termination device into the earth
2. Bto use the lightning high voltage induced by the air-termination device to trigger an overvoltage protection circuit
3. Cto effectively block the lightning current introduced by the air-termination device so it does not flow into the earth
4. Dto quickly blow a fuse and block its flow when the air-termination device introduces lightning current

Regarding the grounding of a lightning protection installation, the most basic requirement is:

1. AThere must be a separate grounding electrode, the grounding resistance must be small, and the down conductor from the air-termination device to the grounding electrode should be as short and thick as possible
2. BA water pipe may be used as the grounding electrode if a substantial length of the pipe is buried underground
3. CThe ‘neutral wire’ of the AC grid is already grounded in the distribution system; this can replace the lightning-protection grounding electrode and its down conductor
4. DThe down conductor from the air-termination device normally carries no current, so a 0.5 mm diameter wire is sufficient

For an ordinary building, how large at most can the protection zone of a single lightning rod be:

1. Athe space between the top of the lightning rod and the ground, enclosed by a rolling-sphere curve of 60 m radius
2. BIn all cases, a lightning rod can protect the space around it that is lower than the rod’s height
3. CIn all cases, a lightning rod can protect objects within a 30 m radius around it
4. Dthe space inside a hemisphere drawn from the rod’s top with the rod’s height as radius

Which of the following conductive materials is most suitable for connecting the various grounded components at the antenna, tower, and incoming feed line?

1. Asilver-plated braided soft-copper strap
2. Bround copper-clad steel single-strand wire
3. CEthernet twisted pair
4. D50-3 coaxial cable

What should be noted when installing a lightning arrester for a coaxial feed line?

1. AConnect the ground wires of all arresters to the same metal strap, then reliably connect the strap to the outdoor grounding point
2. BInstall a switch at each arrester’s ground connection to disconnect during transmission and prevent RF current from damaging the arrester
3. CRun each arrester’s ground wire separately, then connect them together with the radio’s ground wire
4. DYou may make your own arrester cheaply with neon lamps or gas-discharge tubes; such a DIY job is economical and highly effective

Which of the following is an effective measure for lightning-protection grounding of an antenna tower?

1. AThe ground connection should be as short and straight as possible
2. BEnsure that any necessary bends in the ground wire are clean, neat right-angle bends
3. CApply waterproofing to the grounding system
4. DThe grounding electrodes driven into the ground should be as far as possible from the antenna tower

Considering that the actual working environment necessarily has some humidity, then according to the limits for wet conditions in GB/T 3805-2008 ‘Limits for Extra-Low Voltage (ELV)’ (《特低电压ELV限值》), when a person grasps a live part, the voltage between the part and the human body must not exceed:

1. A16 V AC (r.m.s.), 33 V DC
2. B24 V AC (r.m.s.), 36 V DC
3. C36 V AC (r.m.s.), 24 V DC
4. D6.3 V AC (r.m.s.), 13.8 V DC

If the contact voltage is the same, how does the safety threat to the human body from touching a bare conductor carrying radio-frequency voltage (e.g., at a frequency not lower than LF) differ from that of touching a bare conductor carrying DC or 50 Hz AC voltage?

1. AThe risk of fatal injury decreases, but the risk of burning the skin or deep subcutaneous tissue rises significantly
2. BIt more easily causes nervous-system damage or cardiorespiratory dysfunction, posing a higher fatal risk
3. CRF AC never threatens personal safety, so transmitter antennas may be touched casually
4. DTouching AC of different frequencies but the same voltage naturally poses the same safety threat

If you touch with both hands the two endpoints of circuits whose voltage effective values are the same but whose frequencies differ, the order of the safety threat from greatest to least is:

1. Apower-frequency AC, HF RF AC, UHF RF AC
2. BUHF RF AC, HF RF AC, power-frequency AC
3. CHF RF AC, power-frequency AC, UHF RF AC
4. DHF RF AC, UHF RF AC, power-frequency AC

If it is unavoidable and you must repair live radio equipment powered by the mains, you should:

1. Akeep both feet insulated from ground, operate with one hand, and not let the other hand touch the chassis or any metal part connected to the circuit or to grounding
2. Bkeep both feet insulated, operate with one hand, and use the other hand to probe for voltage by touching the chassis or a water pipe as a ground reference
3. Cas long as the equipment chassis is well grounded, insulating your feet or using both hands poses no safety risk
4. Das long as the chassis is insulated from ground, insulating your feet or using both hands is unrelated to safety

A live equipment chassis can endanger personal safety. The relevant preventive measures include: (Choose all that apply.)

1. Afor equipment powered by AC mains, connect its metal enclosure to a reliable common ground
2. Binstall a residual-current device (leakage protector) in the supply line to cut the power quickly in case of leakage
3. Cif a device uses a three-wire plug with a separate protective ground, you must confirm that the grounding is effective
4. Dthe common ground should have low resistance; connecting it to a water-supply pipe is a once-and-for-all good idea

Even after the equipment’s power cord has been unplugged, what safety risk may still be encountered during repairs?

1. Acapacitors still charged to high voltage may expose the repairer to electric-shock risk
2. Bgeomagnetic activity can induce high voltage in the transformer and shock the repairer
3. Copening the case of a power supply or tube linear amplifier blows its internal fuse
4. Dopening the case, electrostatic discharge may damage the equipment’s grounding system

For self-made equipment powered by 220 V AC mains, the safety measures should at least include:

1. Aconnecting a fuse in series in the live wire at the AC inlet
2. Bconnecting an AC voltmeter in parallel at the AC inlet
3. Cconnecting an inductor in series at the AC inlet
4. Dconnecting a capacitor in parallel at the AC inlet

How can you ensure a self-made amateur radio project has high electrical safety? (Choose all that apply.)

1. Ause a three-core power cord and a metal chassis, and reliably connect the chassis to the ground wire of the mains socket
2. Bif the equipment contains a high-voltage rectifier, connect a bleed (discharge) resistor across its filter capacitor
3. Cfit an interlock switch on the homebrew RF power amplifier that disconnects the mains supply when the case is opened
4. Dinstall sprinklers on the distribution box and the antenna-feeder wiring cabinet to spray water immediately on fire

What potential risk exists when using an ordinary 12 V lead-acid battery to power the station?

1. Aif ventilation is poor, explosive gas can accumulate
2. Bit has high voltage, posing an electric-shock risk
3. Cit releases ozone, thereby polluting the atmosphere
4. Dif left unused for a long time it may spontaneously ignite

If a lead-acid battery is charged or discharged too fast, what risk arises?

1. Athe battery may overheat and even release hydrogen, raising the risk of explosion
2. Bthe voltage turns negative and ruins the battery — this is the so-called “reverse polarity”
3. Cit causes a “memory effect”, reducing the battery’s usable capacity
4. Dit may cause excessive battery voltage, raising the risk of electric shock

If electrical equipment, cables, or a power device catches fire, the correct action is:

1. Aimmediately cut all power and extinguish with a dry-powder, carbon-dioxide, or 1211 extinguisher
2. Bimmediately cut all power and extinguish with a foam extinguisher; if forced, use dry sand
3. Cimmediately cut all power and use water
4. Dquickly stand up and flee the scene