Wireless Communications (WCM) — Information & Free Practice
US · Examination information
200 free questions · Answer explanations · No signup required
Wireless Communications (WCM)
- Provider
- ETA International; online or paper/pencil with a Certification Administrator, or ETA-arranged ExamRoom.AI remote proctoring
- Format
- Proctored knowledge examination; no hands-on assessment required
- Exam questions
- Total questions: 100.
- Time limit
- 2 hours
- Passing score
- 75%
- Exam fee
- $80 examination fee; remote proctoring carries an additional fee
Examination outline
Radio Theory
- Electromagnetic transmission and reception
- Radio frequency bands
- Transmitter and receiver blocks
- FCC bandwidth and frequency allocations
- Receiver stages
- Frequency tuning and channel switching
- Propagation by band
Components, Terminology and Symbols
- Electronic components, symbols and uses
Satellite – Data – Telecommunications
- Satellite, GPS, telephone and telecommunications applications
- Interference involving the listed applications
Mobile Systems
- Simplex operation
- Mobile relay simplex and duplex
- Remote and manual control
- RF links
- Commercial and private radio band assignments
- Competing radio services
- Public safety frequencies and bands
- Paging communications
- Single-site and multi-site trunking
- Conventional single-site and multi-site systems
- Simulcast
- Satellite voting
- Wireless data and two-way voice
- CTCSS squelch
- DCSS signaling
- Point-to-point and point-to-multipoint
- Repeater functions
Commercial Radio Networks
- Operational characteristics
- Technical characteristics
- Receiver and transmitter programming
- Trunking concepts
Block Diagrams – Schematics – Flow Charts
- Diagram symbols
- Power and signal tracing
- Schematic test points
- Expected signals and voltages
- Flow chart purposes
Basic Analog Circuits
- AC and DC radio supplies
- Amplifier types, RF and IF stages
- Audio amplifier identification
- AM and FM audio detectors
- AVC and AGC operation
- Transmitter modulators
- Transmitter output components
- Operational amplifier circuits
- Gain measurement
- Bi-directional amplifiers
- PLL and VCO circuits
Hand Tools and Soldering
- Soldering tools and accessories
- Equipment care
- Soldering sequence
- Visual soldering quality
- Desoldering sequence
- Good solder joints
- Solder alloys
- Flux
- Cold and defective joints
- Surface mount replacement
- Wire wrap precautions
- Hot air bonding
- RoHS purpose
- Solder lead forms
Computer and Digital Circuits
- Digital gate symbols and truth tables
- Radio memory devices
- Radio tuning
- Microprocessor control
- RAM, PROM, EEPROM and ROM
- DAC and ADC use
- Modems
- Wireless communication drivers
- TTL and CMOS outputs
Computer Applications
- Computing and software applications in wireless communications
Interfacing
- Interconnection signal levels
- Impedance matching and mismatch
- Two-way radio numbering systems
Transmission Lines, Cabling and Connectors
- Coaxial cable
- Coaxial connector installation
- Routing, bend ratios, tension and regulations
- Transmission line test theory
- Transmission line test equipment
- Impedance matching practices
- Ground loops
- Balanced and unbalanced pairs
- Cable loss
- Cable termination
- FDR principles
- TDR and FDR comparison
- RF connector identification
Antennas and Towers
- Wave propagation speed
- Reception and mobile antennas
- Polar patterns
- Cross polarization
- Antenna gain
- Hand-held transceiver antennas
- Antenna combining
- Diplexers and duplexers
- Cavities, circulators and isolators
- Communications equipment grounding
- Lightning protection devices
- Beam tilt
- Base station antennas
- Receiver multi-coupling
- Tower components and installation
- Transmission site documentation
- Tower top amplifiers
- Attenuator uses
Grounding – Lightning Protection
- Antenna grounding
- Facility grounding standards
- Common grounding electrode systems and NEC requirements
- NEC lightning rules
- Bonding and grounding practices
- Grounding blocks, rods and conductors
- Transient surge protection
- Exothermic welding
Radio Mathematics and Formulas
- dB, dBmV and microvolt conversion
- dBi, dBm, dBW and dBd
- Scientific calculator use
- Technician numbering systems
- Frequency and wavelength
- Effective radiated power
- Effective isotropic radiated power
- Free-space path loss
Modulations Schemes
- AM methods and limits
- FM methods and deviation
- Companding
- Pre-emphasis and de-emphasis
- SSB principles
- TDMA
- CDMA, TDMA and FDMA comparison
- QPSK and OQPSK
- Digital modulation and APCO Project 25
- Encryption and algorithms
- Keyloading
- GSM
Control Systems
- DC remote operation
- Remotes and adapters
- DC system operating signals
- Tone remote operation
- High and low guard tones
- Tone versus DC control
- DTMF applications
- SCADA
- IP remote control
RF Interference
- Receiver de-sensitization
- Spurious emissions and receiver response
- Site compatibility
- Co-channel and adjacent-channel interference
- Image frequency
- Transmitter noise
- Noise floor
- Harmonics and sub-harmonics
- Broadband over power line interference
- Natural noise
- Wind-generated static
- Interference detection
- Inter-modulation causes
- Site filtering and mitigation
- Passive intermodulation
RF Coverage Analysis, Testing and Diagnosis
- RF modeling under TIA TSB 88
- Service area
- Reliability
- Portable configuration effects
- Balanced coverage design
- Coverage verification under TIA TSB 88
- Side-mounted antenna signal distortion
- Common obstructions
Test Equipment and Measurements
- Communications Service Analyzer
- TDR, OTDR and FDR
- SWR and watt meters
- Return, insertion and cable loss
- Signal-to-noise and carrier-to-noise
- Loads, meters, logic tools and generators
- SINAD and audio measurement
- Spectrum analyzers
- RF test cables and converters
- Variable power supplies
- Power measurement
- Frequency and modulation measurement
Troubleshooting
- Circuit defect localization
- Block diagrams and test points
- Heat and cold for intermittent faults
- PC board and surface mount replacement
- Signal overdrive
Workplace Safety for Radio Environment
- 47 CFR Part 15 topics
- Basic FCC two-way radio rules
- Station and technician licenses
- FAA communications rules
- OSHA, fall and ANSI 14 ladder safety
- NEC provisions for radio, antennas and cabling
- Technician workplace environment
- Fire hazards
- Ground faults and shock protection
- Electrostatic discharge
- Fiber optic safety
- Electrical shock potential
- Transmitter RF exposure
- RF monitoring
- Beryllium hazards
- First aid and uncertified worker limits
Examination sources
- WCM Competency Requirements
pp.1–6, scope introduction, categories 1.0–22.0 and closing notes; p.7 checked for continuation
- ETA Communications certifications
Prepare For An Exam and WCM Exam Info competency link
- WCM competency wrapper
WCM Competency, page heading above the embedded PDF
- WCM Competency Requirements
p.6, scope endpoint and redundancy note
- ETA Communications certifications
WCM Exam Info, complete WCM table
- ETA Certification Catalog
p.12, WCM Exam Info table, entire table including header
- ETA test sites
Taking an ETA Examination, steps 6–7
- ETA test sites
Taking an ETA Examination, steps 3–4
- ETA test sites
Remote Proctoring, eligibility, registration and initial scheduling
- ETA test sites
Remote Proctoring, ETA preparation and scheduling restriction
- ETA test sites
Remote Proctoring, initial scheduling note
Related license preparation
This examination may be required or accepted as an alternative, depending on the license and application pathway.