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// Study Notes for Amateur Radio Station Operation Technical Capability Verification
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title: "Study Notes for Amateur Radio Station Operation Technical Capability Verification",
date: "March 16th, 2019",
body: [

I previously took the exam for the amateur radio operation certificate. It's actually quite easy to pass because there are only 370 multiple-choice questions. Since the question bank only contains questions, making it difficult to memorize systematically, I have organized it slightly.

= Legal Documents and Legislation

Radio Management:

- Highest Legal Document: "Radio Management Regulations of the People's Republic of China"
- Legislative Bodies: State Council, Central Military Commission

Amateur Radio Management:

- Highest Legal Document: "Administrative Measures for Amateur Radio Stations"
- Legislative Body: Ministry of Industry and Information Technology (MIIT)

= Management Authorities

Radio Regulatory Authority: Radio regulatory authorities at all levels

Supervisory and Management Body for Amateur Radio Stations: National and local radio management agencies

Local Radio Management Agencies: Provinces, autonomous regions, and municipalities directly under the Central Government

= Spectrum Resources

Lawfully established amateur radio stations are protected by national laws.

According to the "Property Law," radio spectrum resources belong to the state.

"Radio Frequency Allocation Regulations" define amateur service, amateur-satellite service, and amateur radio stations.

Roles of Amateur Service: Self-training, intercommunication, and technical investigation.

= Establishing and Operating a Station

Differences between categories of amateur radio stations: Frequency and Power.

- Category A Frequency Range: Amateur service and amateur-satellite service bands within 30–3000 MHz.
- Category A Power: Not exceeding 25 W.

Age Limit for Establishing a Station: 18 years old. Age Limit for Independent Operation: None.

Conditions for Applying to Establish a Station:

- Familiarity with radio management regulations.
- Possessing the operating capability prescribed by the state.
- Equipment complying with national standards and laws and regulations.

Conditions for Operating a Station:

- Familiarity with management regulations.
- Possessing proof of technical capability prescribed by the state: Marked by obtaining an operation certificate issued by the Chinese Radio Association (CRAC).

Capability Verification Agencies: National and local radio management agencies.

Certificate: Amateur Radio Station Operation Certificate of the Chinese Radio Association (not a sports association).

Steps to Establish a Station:

- Handle approval procedures according to the "Administrative Measures."
- Obtain an amateur radio station license.

Stations with multiple devices: One call sign, all devices must be verified.

Materials submitted for establishing a station: Two types of forms.

Special station types: Repeater stations, beacon stations, space stations.

Applying for a special station: Select the special category in the "Application Form."

Agencies responsible for amateur radio station applications:

- Acceptance: Local radio management agency of the station location and its authorized agencies.
- Approval for stations within a province: Local radio management agency of the station location.
- Approval for trans-provincial stations: National radio management agency or entrusted local management agencies.

= Station Changes

Application for change procedures is required when expanding the scope of communication or transmitting from a different location.

Apply for extension one month before the expiration of the validity period.

Adjusting a radio station: Apply for change, renew license.

Terminating a station: Apply for cancellation to the issuing agency.

Relocating the station site: Cancel first, then re-apply.

= Requirements for Amateur Radio Stations

Characteristics of amateur radio station equipment: Transmit frequency does not exceed amateur bands.

Prescribed indicators:

- Frequency tolerance: Expressed in parts per million (ppm) or Hertz (Hz).
- Spurious emission power: dBm, dBc, dB.

Equipment requirements:

- Commercial products: Must have a Type Approval Certificate.
- Self-made: Pass technical inspection.

Basis for approval: Indicators prescribed in the "Radio Frequency Allocation Regulations."

= Frequency Management

Frequency regulations: "Radio Frequency Allocation Regulations."

Within amateur frequencies, all amateur stations are equal.

- Allocation: The entry of a specific frequency band into the Frequency Allocation Table by the state.
- Allotment: Designation of a radio frequency or channel for use by one or more departments under specified conditions.
- Assignment: Approval of a frequency or channel for use by a specific amateur radio station under specified conditions.

Services are divided into primary services and secondary services:

- Amateur service shall not cause interference to primary services.
- Shall not claim protection from primary services.
- May claim protection from other secondary services.

Frequency bands:

- HF: 3–30 MHz
- VHF: 30–300 MHz
- UHF: 300–3000 MHz
- Exclusive to amateur and amateur-satellite services: 7 MHz, 14 MHz, 28 MHz, 47 GHz.
- Amateur as primary: 50 MHz, 144 MHz.
- Amateur as the sole primary service: 3 bands, 144–146 MHz.
- Secondary service: 135.7 kHz, 10.1 MHz, 430 MHz.

Common names for amateur bands:

- 6 meters: 50–54 MHz, primary service.
- 2 meters: 144–148 MHz, 144–146 MHz is sole primary, 146–148 MHz is co-primary.
- 0.7 meters: 430–440 MHz, secondary.

Primary services for 430–440 MHz: Radiolocation, aeronautical radionavigation.

- 144 MHz bands to avoid occupying: 144–144.035, 145.8–146.
- 430 MHz bands to avoid occupying: 431.9–432.240, 435–438.

= Call Signs

Announce the call sign at the beginning and end of communication, and at least once every ten minutes during communication.

Call signs are assigned at the same time the radio license is issued.

Call signs cannot be changed.

Call sign prefixes and suffixes are compiled and allocated by the national radio management agency and cannot be exceeded.

When relocating across provinces, the call sign may be retained or changed.

Call signs must be complete.

When across provinces, the call sign is formatted as: B9/BH1AAA.

Call sign when guesting at another station: The call sign of that station or one's own call sign with a prefix.

- Guest transmission: Using someone else's station.
- Remote transmission: Using one's own station at a different location.

Prefix is required if retaining the call sign after relocation.

= Communication Regulations

Communication targets of amateur radio stations shall be limited to amateur radio stations.

Without approval from the radio management agency that issued the amateur radio station license, amateur radio stations shall not broadcast in any way or transmit signals of a general broadcast nature.

Plain language and abbreviations and Q-codes recognized in the field of amateur radio should be used at all times.

Experimenting with new encoding, modulation methods, digital communication protocols, or exchanging data files in a format not yet public: Publicize relevant technical details and submit them to the local radio management agency that issued the amateur radio station license.

Do not send signals unrelated to amateur service and amateur-satellite service.

Do not disseminate or publish non-amateur service information.

Do not receive signals unrelated to amateur service and amateur-satellite service.

Ensure that radio transmission equipment is in normal working condition to avoid harmful interference to other radio services.

Persons who have valid legal proof of capability but have not yet been approved to set up their own amateur station may perform transmission operations at an amateur station using that station's call sign.

Remote transmission must comply with the relevant regulations of the local radio management agency of the operation site.

Responsibility of the station establisher: Normal operation, avoiding interference.

Prohibit using amateur radio stations to publish or disseminate information that violates laws or public morals.

Strictly prohibit using amateur radio stations for commercial or other profit-making activities.

Strictly prohibit obstructing communications of other radio stations.

Amateur radio station establishers and users should strengthen self-discipline.

Transmitting stations should only radiate the power necessary to ensure satisfactory service.

Encountering harmful interference: Ignore it, collect relevant information, and report it to the radio management agency.

Amateur radio stations cannot be used for communication with public walkie-talkies.

Only in emergency situations such as sudden major natural disasters can amateur radio stations communicate specified content with non-amateur radio stations. Content is limited to emergency matters directly related to disaster relief or tasks assigned by relevant emergency rescue departments.

= Logs and QSL Cards

Log content:

- Communication time, frequency, mode, opponent's call sign, signal reports from both sides.
- DATE, TIME, FREQ, MODE, CALL (opponent), RST (both sides).

QSL Cards:

- When a party urgently needs a return card, they should mail the card directly to the opponent's address with an attached SASE (Self-Addressed Stamped Envelope).
- When exchanging QSL cards not as proof of contact or listening, notes like "Eye ball QSO" should be filled in; blank cards should not be given.

= Relaying (Repeater)

Relaying must comply with national and local radio management agency regulations of the station site.

Repeater stations designate specific personnel for monitoring and management, equipped with effective remote control means to ensure timely cessation of transmission if harmful interference occurs.

Repeater stations must provide equal service to all amateur radio stations and publicize various technical parameters required for using the amateur repeater.

Frequency offset for amateur analog FM repeaters in the same band:

- 600 kHz for the 144 MHz band.
- 5 MHz for the 430 MHz band.

Except for necessary brief communications, amateur repeaters should be kept with sufficient idle time to respond to emergency calls for sudden disasters at any time.

Calling on a repeater: Call the opponent's call sign and announce your own call sign.

= Legal Management

Amateur radio stations are subject to supervision and inspection by radio management agencies or their entrusted units.

Radio Control:

- Mandatory management of emission, radiation, and propagation of radio waves within specific times and areas.
- Restricting or prohibiting the use of amateur radio stations, and implementing technical blocking of specific radio frequencies, etc.
- Decision to implement: Implementation nationwide or across provinces, autonomous regions, and municipalities is decided by the State Council and the Central Military Commission. Implementation within a province, autonomous region, or municipality is decided by the people's government of the province, autonomous region, or municipality and relevant military districts.
- Violation of control: Handled by national or provincial radio management agencies; violators of public security management regulations are punished by public security organs.
- Penalties: Order for correction; for those who refuse to correct, closing, sealing, temporary detention, or dismantling of relevant equipment; in serious cases, revocation of the station license; violators of public security management regulations are punished by public security organs.

Any approved amateur station enjoys equal rights to use frequencies.

= Communication Norms

Before calling: Listen for a period to ensure no other stations are using the frequency. Ask "Is the frequency in use?" first. Initiate a call only after confirming no response.

During testing: First set the frequency to an idle frequency not in use by anyone, deviating from commonly used hotspot frequencies.

CQ refers to calling any station non-specifically.

CQ Call Format:

- CQ, CQ, CQ. This is BH1ZZZ. Bravo Hotel One Zulu Zulu Zulu calling. BH1ZZZ calling. Listening for any calls.
- CQ CQ CQ. This is BH1ZZZ. Bravo Hotel One Zulu Zulu Zulu, BH1ZZZ is calling. I'm standing by.

Answering CQ: First report the opponent's call sign, then your own.

Format for calling other specific stations:

- BH8YYY, BH8YYY, BH8YYY. This is BH1ZZZ. Bravo Hotel One Zulu Zulu Zulu calling. BH1ZZZ calling. Listening for a reply.
- Bravo Hotel Eight Yankee Yankee Yankee, Bravo Hotel Eight Yankee Yankee Yankee, Bravo Hotel Eight Yankee Yankee Yankee. This is Bravo Hotel One Zulu Zulu Zulu. Bravo Hotel One Zulu Zulu Zulu, Bravo Hotel One Zulu Zulu Zulu is calling. I'm standing by.

Insertion: During a gap in the conversation between two parties, briefly transmit "Break in!" or "Insertion!". If a response is received, then state your call sign "BH1ZZZ requesting insertion." Only after the opponent officially expresses an invitation can you join.

Before inserting, confirm that your joining will not affect the enjoyment of the original communication parties.

= Abbreviations (Q-Codes)

- QRZ: Who is calling me?
- QRM: I am experiencing interference from another station.
- QRN: I am experiencing atmospheric noise (static).
- QSL: I give you acknowledgment/I have received.
- QTH: My station location is.
- ANT: Antenna.
- ARDF: Amateur Radio Direction Finding.
- FREQ: Frequency.
- GND: Ground.
- OM: Old Man (Old friend).
- RIG: Radio equipment.
- RCVR, RX: Receiver.
- XMTR, TX: Transmitter.
- XCVR: Transceiver.
- WX: Weather.
- 73: Best regards.
- Roger: Understood.
- DP: Dipole antenna.
- GP: Ground Plane antenna.
- BEAM: Directional antenna.
- YAGI: Yagi antenna.
- VER: Vertical antenna.

= Zones

CQ Zones China belongs to:

- 23
- 24
- 27

ITU Zones China belongs to:

- 33
- 42
- 43
- 44
- 50

Grid Locator: A geographical location determined by a string of letters and numbers.

Maidenhead Grid Locator System:

- A system for partitioning and naming the Earth's surface into grids based on latitude and longitude coordinates to mark geographical locations.
- Format: 2 letters and 2 digits, 2 letters and 2 digits plus another 2 letters.
- 4-character or 6-character: Different grid sizes; a 4-character grid is 2 degrees longitude and 1 degree latitude, while a 6-character grid is 5 minutes longitude and 2.5 minutes latitude.

= Communication Principles

- lg 5 = 0.7
- lg 2.5 = 0.4
- lg 4 = 0.6

Rated Power: Maximum power when components are working normally.

Bandwidth for FM voice communication: 6.25 kHz.

Basic Radio Receiving System: Receiving antenna, demodulator, output device.

Basic Transmitting System: RF oscillator, modulator, transmitting antenna.

Role of Transmitting Antenna: Convert RF signal into electromagnetic waves. Role of Receiving Antenna: Convert electromagnetic waves into RF signal.

Excellent Receiver:

- Good anti-interference capability.
- Sufficiently high sensitivity.
- Minimal internal noise and signal distortion.

Filter: Frequency distortion.

Factors determining FM output signal bandwidth:

- Highest frequency of the signal being transmitted.
- Amplitude.

Frequency Discrimination: Demodulate FM signals.

Transmitter Efficiency: Output antenna power / Transmitter supply power.

Squelch Sensitivity: Minimum RF input level required to deactivate the squelch circuit.

- Attenuation: Power reduction of a signal after passing through a channel or circuit.
- Fading: Fluctuations in the amplitude of a signal over time after passing through a channel or circuit.

Carrier Power: Power in the absence of modulation.

CTCSS (Continuous Tone-Coded Squelch System): Adding a sub-audible low-frequency tone to the transmitted voice signal to open the receiver's squelch.

FM frequency deviation is determined by the amplitude of the modulated signal.

A receiver's ability to distinguish different signals: Selectivity.

Overload: Input signal is too strong, leading to additional internal interference.

- Long-distance weak signal UV contact: SSB.
- Local communication: FM.

Reason switching power supplies are lightweight: Working frequency is much higher, allowing for smaller magnetic material cross-sections and fewer coil turns.

= Antenna

Ideal working state of an antenna-feeder system composed of a half-wave dipole antenna and feeder cable: Only standing waves on the antenna, only traveling waves on the feeder.

Length of vertical ground plane antenna element with main radiation lobe near zero elevation angle: Odd multiples of 1/4 wavelength.

RF Cable Parameters:

- Characteristic Impedance.
- Power Loss.

Vertical dipole or vertical ground plane antennas are called "omnidirectional antennas": No directivity in the horizontal direction, but directional in 3D space.

Maximum radiation direction of a vertical ground plane antenna with an electrical length of 1/4 wavelength:

- Omnidirectional in the horizontal plane.
- Directed towards the horizon in the vertical plane.

Reasons for a vertical ground plane antenna (GP) being non-ideal:

- Lack of an effective ground reflector. GP antennas must have a sufficiently large ground reflector to form a mirror image of the element; otherwise, the resonant frequency and impedance will deviate significantly from theoretical values.
- Try to use a large area of metal directly connected to the antenna's ground end.

Antenna Gain:

- Ratio of radiation power density of an antenna in its maximum radiation direction to that of a reference antenna under the same conditions.
- dBi: Relative to an isotropic antenna.
- dBd: Relative to a half-wave dipole antenna.
- dB: Meaningless without reference.

dBd = dBi - 2.15

Reducing induced RF current on the outer sheath of an audio coaxial cable: Wrap a ferrite magnetic ring around the outside of the cable.

Dummy Load: Prevents radio signals from actually being transmitted during equipment testing.

Measuring Antenna Resonant Frequency: Antenna Analyzer.

Standing Wave Ratio (SWR) can: Measure the matching quality between the load and the transmission line; 1:1 is perfect.

Power loss in the feeder is converted into heat.

Electromagnetic waves emitted by a vertical antenna have an electric field perpendicular to the ground.

Rubber ducky antennas have lower transmission and reception efficiency.

= Coaxial Cable

Role of coaxial cable: Transmit radio signals from the transmitter to the antenna.

Main cause of coaxial cable damage: Moisture.

Ultraviolet rays can damage the cable sheath, leading to moisture ingress.

Air-dielectric cables require special means to prevent moisture from entering.

Reducing the SWR of a coaxial cable allows energy to be transmitted more efficiently, reducing losses.

Coaxial cables are convenient to use and have little mutual interaction with the surrounding environment.

The higher the frequency, the higher the loss in a coaxial cable.

For signals above 400 MHz, N-type connectors are usually used for coaxial cables.

Poor contact in the connector between the antenna and the feeder may lead to unstable SWR readings.

Air-dielectric hardline coaxial cables have the lowest loss in the UV bands.

- Antenna wire velocity factor: 0.95c.
- Coaxial cable velocity factor: 0.65c.

= Wave Propagation

Radio wave propagation modes:

- Ground wave.
- Sky wave.
- Space wave.
- Scattering wave.

Path Loss:

- Proportional to the square of the distance.
- Proportional to the square of the frequency.

Ground wave attenuation factors:

- Wave frequency.
- Ground conductivity.
- Propagation distance.

Line-of-sight transmission limit for ultra-short waves: Determined by height.

Multipath propagation leads to increased bit error rate in UV communications.

VHF signals may be reflected by sporadic-E layers of the ionosphere.

RF: Stands for various radio waves.

= Radio Usage

- VOX: Voice-Operated Exchange (hands-free transmission).
- PTT: Push-To-Talk.
- SQL: Squelch control.
- NFM: Narrowband FM (25 kHz / 12.5 kHz).
- WFM: Wideband FM (180 kHz).
- DTMF: Dual-Tone Multi-Frequency.
- CTCSS: Sub-audible tone squelch.
- NFM receiving WFM: Non-linear distortion.
- WFM receiving NFM: Low volume.

Possible reasons for poor signal:

- Insufficient supply voltage to the radio.
- Poor location of the radio.
- Inaccurate transmit frequency of the radio.
- Full deviation: 25 kHz.
- Half deviation: 12.5 kHz.

= Safety

Harmonic radiation from switching power supplies may cause interference.

Microwave ovens generally operate in UHF.

Vehicle radio voltage: 12 V.

UV signals belong to non-ionizing radiation.

Lightning protection device composition:

- Air terminal (lightning rod).
- Down conductor.
- Grounding body.

Role of lightning protection grounding: Effectively discharge the lightning strike current introduced by the air terminal into the ground.

Basic requirements for lightning protection grounding:

- Have a separate grounding body.
- Grounding resistance should be small.
- The down conductor from the air terminal to the grounding body should be as short and thick as possible.

Protection range of a single lightning rod: Space within a 45-degree cone with the lightning rod as the apex.

Safe voltage: 24 V.

Exposed RF conductors: Lethal danger decreases, but skin is easily burned.

Prioritize CO2 fire extinguishers.

When performing live maintenance on mains-powered radio equipment:

- Insulate both feet from the ground.
- Operate with one hand.
- The other hand should not touch the chassis or any metal items related to the circuit equipment.

When installing lightning arresters for coaxial cable feeders: Connect the grounds of all arresters to the same metal plate, then connect this metal plate to an outdoor grounding electrode.

After unplugging equipment from the power source, capacitors filled with high voltage may still cause an electric shock.

= Electromagnetic Radiation Pollution

Suppose a repeater's transmitter and receiver share an antenna, with uplink and downlink frequencies F1 and F2 respectively. To prevent the repeater's transmitter from interfering with the receiver:

- Connect a band-stop filter with center frequency F1 in series between the transmitter and the antenna.
- Connect a band-stop filter with center frequency F2 in series between the receiver and the antenna.

To prevent spurious emissions from an amateur HF transmitter from interfering with a telephone near the antenna, you should connect in series between the telephone and the telephone line: A low-pass filter with a cutoff frequency no higher than 1 MHz.

Specific management regulation document for electromagnetic radiation pollution: National Standard "Regulations for Electromagnetic Radiation Protection."

Electromagnetic radiators exempt from management:

- Mobile radio communication equipment with output power not exceeding 15 W.
- Equivalent radiated power not exceeding 300 W in the 0.1–3 MHz range.
- Equivalent radiated power not exceeding 100 W in the 3 MHz–300 GHz range.

If power is greater than the exemption level: Declare and register with the local environmental protection department and accept supervision.

The owner is responsible for monitoring electromagnetic radiation levels.

When monitored electromagnetic radiators exceeding the exemption level cause environmental radiation to exceed prescribed limits: Take measures as soon as possible to reduce radiation levels and report to the environmental protection department.

Monitoring of environmental electromagnetic radiation levels for radiators exceeding the exemption level should be conducted at: Points selected along the maximum radiation direction within 2000 meters of the radiator antenna.

Basic limit for public exposure in electromagnetic radiation protection limits: The average Specific Absorption Rate (SAR) for the whole body within any 6-minute period during 24 hours a day should be less than the limit per kilogram of body weight.

The frequency range with the strictest requirements for the average value of environmental electromagnetic field strength within any 6-minute period during 24 hours a day is: 30 MHz — 3 GHz.

The human body absorbs more electromagnetic waves at certain specific frequencies.

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