All 23 Ham Radio Technician questions for T4 Station Setup & Practices with the correct answers marked and a short explanation for each, from the official 2026-2030 question pool. Test yourself with the free practice exam.
T4A01
Which of the following is an appropriate power supply rating for a typical 50-watt output mobile FM transceiver?
A. 24.0 volts at 4 amperes
B. 13.8 volts at 4 amperes
C. 24.0 volts at 12 amperes
D. 13.8 volts at 12 amperes ✓
Why: Mobile radios run on vehicle voltage, nominally 13.8 volts DC. Because a transmitter is only about 40 to 50 percent efficient, a 50-watt mobile draws roughly 10 amps or more at full power, so a 12-amp supply is appropriate. A 4-amp supply is too small.
T4A02
Which of the following should be considered when selecting an accessory SWR meter?
A. The frequency and power level at which the measurements will be made ✓
B. The distance that the meter will be located from the antenna
C. The maximum SWR anticipated on the transmission line
D. The ability of the meter to compensate for a poor transmission line match to the antenna
Why: SWR meters are designed for specific frequency ranges and power levels. Choose one rated for the bands and transmitter power you will use, or readings may be inaccurate or the meter damaged.
T4A03
Why are short, heavy-gauge wires used for a transceiver’s DC power connection?
A. To minimize voltage drop when transmitting ✓
B. To provide a close match to the power supply output impedance
C. To avoid RF interference
D. To minimize radiative losses in the power cable
Why: A transceiver draws high current when transmitting. Wire resistance causes a voltage drop equal to I x R, so short, heavy-gauge (low-resistance) wires keep the voltage at the radio close to the supply voltage.
T4A04
How are the audio input and output of a transceiver connected in a station configured to operate using FT8?
A. To a computer running a terminal program and connected to a terminal node controller unit
B. To the audio output and input of a computer running FT8 software ✓
C. To an FT8 conversion unit, a keyboard, and a computer monitor
D. To a computer connected to the FT8converter.com website
Why: FT8 software on a computer generates and decodes the audio tones. The radio's receive audio goes to the computer's audio input, and the computer's audio output feeds the radio's transmit audio input.
T4A05
Where should an RF power meter be installed?
A. In the feed line, between the transmitter and antenna ✓
B. At the power supply output
C. In parallel with the push-to-talk line and the antenna
D. In the power supply cable, as close as possible to the radio
Why: An RF power meter measures the RF energy going to the antenna, so it must be inserted in the feed line between the transmitter and antenna. It is not used in the DC power or control lines.
T4A06
What signals are used in a computer-radio interface for digital mode operation?
A. Receive and transmit mode, status, and location
B. Antenna and RF power
C. Receive audio, transmit audio, and transmitter keying ✓
D. NMEA GPS location and DC power
Why: A computer-radio interface for digital modes carries receive audio to the computer, transmit audio from the computer, and a keying (push-to-talk) signal so the computer can switch the radio into transmit.
T4A07
Which of the following is one of the connections required between a computer and a transceiver to operate digital modes?
A. Computer “line out” to transceiver push-to-talk
B. Computer “line in” to transceiver push-to-talk
C. Computer “line in” to transceiver speaker connector ✓
D. Computer “line out” to transceiver speaker connector
Why: The computer must hear what the radio receives, so the transceiver's speaker or audio output connects to the computer's 'line in.' Line out would feed transmit audio, not connect to a speaker or PTT.
T4A08
Which of the following conductors is preferred for bonding at RF?
A. Copper braid removed from coaxial cable
B. Copper-clad steel wire
C. Twisted-pair cable
D. Flat copper strap ✓
Why: At RF, current flows on conductor surfaces (skin effect), and wide, flat copper strap has a large surface area and low inductance. That makes it the best choice for RF bonding between equipment.
T4A09
How can you determine the length of time that equipment can be powered from a battery?
A. Divide the watt-hour rating of the battery by the peak power consumption of the equipment
B. Divide the battery ampere-hour rating by the average current draw of the equipment ✓
C. Multiply the watts per hour consumed by the equipment by the battery power rating
D. Multiply the square of the current rating of the battery by the input resistance of the equipment
Why: Operating time equals battery capacity divided by current draw. For example, a 20 ampere-hour battery powering a radio that averages 4 amps lasts about 20 / 4 = 5 hours.
T4A10
What function does a digital mode hotspot perform for nearby transceivers?
A. Communication with a digital voice or data network ✓
B. FT8 digital communications via AFSK using a smartphone connected to the internet
C. RTTY encoding and decoding without a computer
D. High-speed digital communications for meteor scatter
Why: A digital mode hotspot is a small, low-power device that links nearby digital voice radios (DMR, D-STAR, etc.) to a digital voice or data network over the internet.
T4A11
Where should the negative power return of a mobile transceiver be connected in a vehicle?
A. At the 12-volt battery chassis ground ✓
B. To the shell of the power connector
C. To any metal part of the vehicle
D. Through the transceiver’s mounting bracket
Why: Connect the negative lead directly at the battery's chassis ground connection. Random metal parts or mounting brackets may have poor or noisy connections that cause voltage drop and interference.
T4A12
What is an electronic keyer?
A. A device for switching antennas from transmit to receive
B. A device for voice activated switching from receive to transmit
C. A device that assists in manual sending of Morse code ✓
D. An interlock to prevent unauthorized use of a radio
Why: An electronic keyer uses paddles to automatically generate correctly timed Morse code dots and dashes, helping an operator send manually with consistent spacing. It is not a T/R switch or VOX.
T4B01
What is the effect of excessive microphone gain on SSB transmissions?
A. Frequency instability
B. Distorted transmitted audio ✓
C. Increased SWR
D. Sideband inversion
Why: Too much microphone gain overdrives the transmitter, causing distorted audio and splatter onto adjacent frequencies. Adjust gain so speech is clean, typically using the ALC meter as a guide.
T4B02
Which of the following can be used to enter a transceiver’s operating frequency?
A. The keypad or VFO knob ✓
B. The CTCSS or DTMF encoder
C. The Automatic Frequency Control
D. All these choices are correct
Why: Most transceivers set the operating frequency either by typing it on the keypad or by turning the VFO (variable frequency oscillator) tuning knob. CTCSS and DTMF are tone signaling functions.
T4B03
How is squelch adjusted so that a weak FM signal can be heard?
A. Set the squelch threshold so that receiver output audio is on all the time ✓
B. Turn up the audio level until it overcomes the squelch threshold
C. Turn on the anti-squelch function
D. Enable squelch enhancement
Why: To hear very weak FM signals, set the squelch so the audio is open (unmuted) all the time. You will hear background noise, but weak signals below the squelch threshold will not be cut off.
T4B04
What does an FM signal sound like when received slightly off frequency?
A. The audio increases in pitch
B. The audio decrease in pitch
C. There is no effect except for reduction in amplitude
D. The audio becomes distorted ✓
Why: An FM receiver tuned slightly off frequency only partly captures the signal's deviation, so the recovered audio becomes distorted. Pitch changes from mistuning happen with SSB, not FM.
T4B05
What does the scanning function of an FM transceiver do?
A. Checks incoming signal deviation
B. Prevents interference to nearby repeaters
C. Tunes through a range of frequencies to check for activity ✓
D. Tunes through a range of frequencies to determine the antenna’s resonant frequency
Why: Scanning automatically tunes through a range of frequencies or memory channels, pausing on active signals so you can find activity without tuning manually.
T4B06
Which of the following controls could be used if the voice pitch of a single-sideband signal returning to your CQ call seems too high or low?
A. The AGC or limiter
B. The bandwidth selection
C. The tone squelch
D. The RIT or Clarifier ✓
Why: RIT (receiver incremental tuning), also called a clarifier, shifts the receive frequency slightly without changing your transmit frequency. It corrects SSB voices that sound too high or low in pitch.
T4B07
What is a DMR “code plug”?
A. An adapter cable used to connect a DMR radio to a computer for internet access
B. Configuration data loaded onto your radio to access repeaters and talkgroups ✓
C. An upgrade to DMR programming software provided by the radio manufacturer to accommodate new radio models
D. A Coder-Decoder (CODEC) that converts analog voice data to DMR digital data and vice versa
Why: A DMR code plug is the configuration file, often created with programming software, containing frequencies, color codes, talkgroups and contacts so the radio can access repeaters and talkgroups.
T4B08
What is the advantage of having a choice of receiver filter bandwidths in a multimode transceiver?
A. Permits monitoring several modes simultaneously by selecting a separate filter for each mode
B. Permits noise or interference reduction by selecting a bandwidth matching the mode ✓
C. Increases the number of frequencies that can be stored in memory
D. Increases the amount of offset between receive and transmit frequencies
Why: Using a filter bandwidth that matches the signal, such as narrow for CW and about 2.4 kHz for SSB, removes noise and interference outside the wanted signal while keeping the signal itself.
T4B09
How is a specific group of stations selected on a DMR digital voice transceiver?
A. By retrieving the frequencies from transceiver memory
B. By enabling the group’s CTCSS tone
C. By entering the group’s identification code ✓
D. By inserting a five-pin, pre-programmed code plug
Why: On a DMR radio, a talkgroup is selected by entering or choosing its identification code, usually stored in the code plug. CTCSS tones are used for analog FM, not DMR talkgroups.
T4B10
Which of the following receiver filter bandwidths provides the best signal-to-noise ratio for SSB reception?
A. 500 Hz
B. 1000 Hz
C. 2400 Hz ✓
D. 5000 Hz
Why: An SSB voice signal is about 2.4 to 3 kHz wide. A 2400 Hz filter passes the voice while rejecting extra noise. Narrower filters cut off speech, and 5000 Hz admits unnecessary noise.
T4B11
Which of the following must be programmed into a D-STAR digital transceiver before transmitting?
A. Your call sign ✓
B. Your output power
C. The codec type being used
D. All these choices are correct
Why: D-STAR transmits your call sign digitally with every transmission, so your call sign must be programmed into the radio before you transmit. Power and codec are not required settings for this.