Every question in the official Element 3 General pool, with the correct answer and an explanation. Your exam will be 35 of these questions, one from each group.
Testing on or after July 1, 2027? A new General pool takes effect that day. This page covers the 2023-2027 pool used for exams through June 30, 2027. We will add the new pool when NCVEC releases it.
Source: NCVEC Question Pool Committee, 2023-2027 General Class FCC Element 3 Question Pool (public domain). Question and answer text are reproduced exactly; explanations are written by HamTestHub. See all sources.
Withdrawn questions: NCVEC has removed G1A04, G1C08, G1C09, G1C10, G1E09, G6B09, G8C01, G9C06, G9D13 from the pool. They will not appear on exams and are not listed here.
5 exam questions from this subelement. Practice G1 · Study notes
On which HF and/or MF amateur bands are there portions where General class licensees cannot transmit?
Answer C. On 80, 40, 20 and 15 meters, some segments are reserved for Amateur Extra (and, on some bands, Advanced) licensees. General licensees cannot transmit there.
On which of the following bands is phone operation prohibited?
Answer B. 30 meters is a narrow band limited to CW and data. Phone (voice) is not allowed there.
On which of the following bands is image transmission prohibited?
Answer B. 30 meters is limited to CW and data, so image modes such as SSTV are not permitted.
On which of the following frequencies are General class licensees prohibited from operating as control operator?
Answer A. 7.125 to 7.175 MHz is reserved for Extra and Advanced class licensees. General phone privileges on 40 meters start at 7.175 MHz.
Which of the following applies when the FCC rules designate the amateur service as a secondary user on a band?
Answer C. As a secondary user, amateurs must not cause harmful interference to primary users, and must accept any interference they receive from them.
On which amateur frequencies in the 10-meter band may stations with a General class control operator transmit CW emissions?
Answer D. CW is permitted everywhere in the 10-meter band, so a General licensee may send CW on the entire band.
Which HF bands have segments exclusively allocated to Amateur Extra licensees?
Answer B. Amateur Extra-only segments exist on 80, 40, 20 and 15 meters.
Which of the following frequencies is within the General class portion of the 15-meter band?
Answer C. The General portion of 15 meters includes 21.025 to 21.200 MHz (CW/data) and 21.275 to 21.450 MHz (phone). 21300 kHz (21.300 MHz) falls in the General phone segment.
What portion of the 10-meter band is available for repeater use?
Answer D. Repeaters are permitted on 10 meters only above 29.5 MHz.
When General class licensees are not permitted to use the entire voice portion of a band, which portion of the voice segment is available to them?
Answer B. Where General licensees share a phone band with higher classes, they get the upper frequency portion. The lower portion is for Extra (and Advanced) licensees.
What is the maximum height above ground for an antenna structure not near a public use airport without requiring notification to the FAA and registration with the FCC?
Answer C. An antenna structure up to 200 feet high, not near a public-use airport, does not require FAA notification or FCC registration.
With which of the following conditions must beacon stations comply?
Answer A. Only one beacon may transmit in the same band from the same station location.
Which of the following is a purpose of a beacon station as identified in the FCC rules?
Answer A. Part 97 defines a beacon's purpose as observation of propagation and reception.
Which of the following transmissions is permitted for all amateur stations?
Answer C. All amateur stations may occasionally retransmit weather and propagation forecast information from U.S. government stations.
Which of the following one-way transmissions are permitted?
Answer B. One-way transmissions to help people learn Morse code (code practice) are permitted.
Under what conditions are state and local governments permitted to regulate amateur radio antenna structures?
Answer D. Under the PRB-1 federal preemption, state and local rules must reasonably accommodate amateur communications. They must be the minimum practical regulation to achieve the government's legitimate purpose.
What are the restrictions on the use of abbreviations or procedural signals in the amateur service?
Answer B. Abbreviations and procedural signals are allowed as long as they do not obscure the meaning of a message.
When is it permissible to communicate with amateur stations in countries outside the areas administered by the Federal Communications Commission?
Answer B. You may contact amateurs in any country except those whose administrations have notified the ITU that they object.
On what HF frequencies are automatically controlled beacons permitted?
Answer D. Automatically controlled HF beacons are permitted only from 28.20 to 28.30 MHz.
What is the power limit for beacon stations?
Answer C. Beacon stations are limited to 100 watts PEP output.
Who or what determines “good engineering and good amateur practice,” as applied to the operation of an amateur station in all respects not covered by the Part 97 rules?
Answer A. The FCC decides what counts as good engineering and good amateur practice (97.101(a)).
What is the maximum transmitter power an amateur station may use on 10.140 MHz?
Answer A. 10.140 MHz is in the 30-meter band, where the maximum is 200 watts PEP output.
What is the maximum transmitter power an amateur station may use on the 12-meter band?
Answer C. 12 meters allows the full 1500 watts PEP output.
What is the maximum bandwidth permitted by FCC rules for amateur radio stations transmitting on USB frequencies in the 60-meter band?
Answer A. On the 60-meter channels, USB signals may be no wider than 2.8 kHz.
Which of the following is required by the FCC rules when operating in the 60-meter band?
Answer A. On 60 meters, power is specified as ERP relative to a dipole. If you use an antenna other than a dipole, you must keep a record of its gain.
What is the limit for transmitter power on the 28 MHz band for a General Class control operator?
Answer C. On 10 meters, a General control operator may use up to 1500 watts PEP output.
What is the limit for transmitter power on the 1.8 MHz band?
Answer D. 160 meters (1.8 MHz) allows up to 1500 watts PEP output.
What must be done before using a new digital protocol on the air?
Answer C. Before using a new digital protocol on the air, its technical characteristics must be publicly documented, so others can decode and monitor it.
What measurement is specified by FCC rules that regulate maximum power?
Answer D. FCC power limits are specified as PEP (peak envelope power) output from the transmitter.
Who may receive partial credit for the elements represented by an expired amateur radio license?
Answer A. Anyone who can show they once held a General, Advanced or Extra license that was not revoked gets credit for the elements it represents. They must pass the current Element 2 (Technician) exam.
What license examinations may you administer as an accredited Volunteer Examiner holding a General class operator license?
Answer C. A General class VE may give only the Technician exam. Higher exams need VEs of higher class.
On which of the following band segments may you operate if you are a Technician class operator and have an unexpired Certificate of Successful Completion of Examination (CSCE) for General class privileges?
Answer C. With an unexpired CSCE for General, a Technician may operate on any General or Technician band segment right away, adding "AG" to their call sign.
Who must observe the administration of a Technician class license examination?
Answer A. Every license exam session must be observed by at least three VEs. For the Technician exam, they must be General class or higher.
When operating a US station by remote control from outside the country, what license is required of the control operator?
Answer A. To control a U.S. station by remote control from abroad, you need a U.S. operator/primary station license.
Until an upgrade to General class is shown in the FCC database, when must a Technician licensee identify with “AG” after their call sign?
Answer A. Until the upgrade appears in the FCC database, a Technician using General privileges must add "AG" after their call sign.
Volunteer Examiners are accredited by what organization?
Answer C. Volunteer Examiners are accredited by a Volunteer Examiner Coordinator (VEC).
Which of the following criteria must be met for a non-US citizen to be an accredited Volunteer Examiner?
Answer B. A non-U.S. citizen can be a VE if they hold an FCC-granted amateur license of General class or above.
How long is a Certificate of Successful Completion of Examination (CSCE) valid for exam element credit?
Answer C. A CSCE gives exam element credit for 365 days.
What is the minimum age that one must be to qualify as an accredited Volunteer Examiner?
Answer B. Accredited Volunteer Examiners must be at least 18 years old.
What action is required to obtain a new General class license after a previously held license has expired and the two-year grace period has passed?
Answer D. After the 2-year grace period, a former licensee must show proof of the expired license and pass the current Element 2 exam to get the license class back.
When operating a station in South America by remote control over the internet from the US, what regulations apply?
Answer C. When you remotely control a station located in another country, only that country's regulations apply.
Which of the following would disqualify a third party from participating in sending a message via an amateur station?
Answer A. A person whose amateur license has been revoked and not reinstated may not act as a third party. Citizenship and language are not restrictions.
When may a 10-meter repeater retransmit the 2-meter signal from a station that has a Technician class control operator?
Answer D. A 10-meter repeater may retransmit a Technician's 2-meter signal only if the 10-meter repeater's control operator holds at least a General license.
What is required to conduct communications with a digital station operating under automatic control outside the automatic control band segments?
Answer A. To contact an automatically controlled digital station outside the automatic-control segments, the station initiating the contact must be under local or remote control.
Which of the following conditions require a licensed amateur radio operator to take specific steps to avoid harmful interference to other users or facilities?
Answer D. All of these require steps to avoid interference: operating near an FCC monitoring station, using bands where amateurs are secondary, and transmitting spread spectrum.
What are the restrictions on messages sent to a third party in a country with which there is a Third-Party Agreement?
Answer C. Third-party messages must relate to amateur radio, be remarks of a personal character, or relate to emergencies or disaster relief.
The frequency allocations of which ITU region apply to radio amateurs operating in North and South America?
Answer C. North and South America are in ITU Region 2.
In what part of the 2.4 GHz band may an amateur station communicate with non-licensed Wi-Fi stations?
Answer D. Amateur stations may communicate only with other amateur stations. There is no part of 2.4 GHz where they may communicate with unlicensed Wi-Fi stations.
What is the maximum PEP output allowed for spread spectrum transmissions?
Answer B. Spread spectrum transmissions are limited to 10 watts PEP output.
Why should an amateur operator normally avoid transmitting on 14.100, 18.110, 21.150, 24.930 and 28.200 MHz?
Answer A. 14.100, 18.110, 21.150, 24.930 and 28.200 MHz host an international network of propagation beacons (the NCDXF/IARU beacons). Avoid transmitting on them.
On what bands may automatically controlled stations transmitting RTTY or data emissions communicate with other automatically controlled digital stations?
Answer D. Automatically controlled digital stations may communicate with each other anywhere on 6 meters and shorter wavelengths, and in limited segments of some HF bands.
When may third-party messages be transmitted via remote control?
Answer A. Third-party messages may be sent via remote control under any circumstances where FCC rules permit third-party messages.
5 exam questions from this subelement. Practice G2 · Study notes
Which mode is most commonly used for voice communications on frequencies of 14 MHz or higher?
Answer A. By convention, upper sideband (USB) is used for voice on 14 MHz (20 meters) and higher.
Which mode is most commonly used for voice communications on the 160-, 75-, and 40-meter bands?
Answer B. By convention, lower sideband (LSB) is used for voice on 160, 75 and 40 meters, the bands below 10 MHz.
Which mode is most commonly used for SSB voice communications in the VHF and UHF bands?
Answer A. SSB on VHF and UHF normally uses upper sideband.
Which mode is most commonly used for voice communications on the 17- and 12-meter bands?
Answer A. 17 and 12 meters are above 14 MHz, so upper sideband is the convention.
Which mode of voice communication is most commonly used on the HF amateur bands?
Answer C. Single sideband is the most common voice mode on HF.
Which of the following is an advantage of using single sideband, as compared to other analog voice modes on the HF amateur bands?
Answer D. SSB uses less bandwidth than AM and puts all its power into one sideband, so it is more power-efficient.
Which of the following statements is true of single sideband (SSB)?
Answer B. In SSB, only one sideband is transmitted. The carrier and the other sideband are suppressed.
What is the recommended way to break into a phone contact?
Answer B. To break into a phone contact, say your call sign once during a pause.
Why do most amateur stations use lower sideband on the 160-, 75-, and 40-meter bands?
Answer D. There is no technical reason for LSB below 10 MHz. It is simply commonly accepted amateur practice.
Which of the following statements is true of VOX operation versus PTT operation?
Answer B. VOX (voice-operated transmit) switches to transmit when you speak, allowing hands-free operation.
Generally, who should respond to a station in the contiguous 48 states calling “CQ DX”?
Answer C. "CQ DX" from the lower 48 states invites stations outside the contiguous 48 states to answer.
What control is typically adjusted for proper ALC setting on a single sideband transceiver?
Answer B. ALC (automatic level control) is set by adjusting the transmit audio or microphone gain so the ALC stays within its recommended range.
Which of the following is true concerning access to frequencies?
Answer C. No station has priority access to any frequency, except in emergencies (97.101(b)).
What is the first thing you should do if you are communicating with another amateur station and hear a station in distress break in?
Answer B. First acknowledge the station in distress and find out what help is needed. Distress traffic takes priority.
What is good amateur practice if propagation changes during a contact creating interference from other stations using the frequency?
Answer C. When changing propagation causes interference, work out a solution with the other stations in a mutually acceptable way.
When selecting a CW transmitting frequency, what minimum separation from other stations should be used to minimize interference to stations on adjacent frequencies?
Answer B. CW signals are narrow. A separation of 150 to 500 Hz is usually enough to avoid interfering with nearby stations.
When selecting an SSB transmitting frequency, what minimum separation should be used to minimize interference to stations on adjacent frequencies?
Answer C. An SSB signal is about 3 kHz wide, so allow 2 to 3 kHz of separation from other SSB stations.
How can you avoid harmful interference on an apparently clear frequency before calling CQ on CW or phone?
Answer A. Before calling, ask if the frequency is in use: send "QRL?" plus your call sign on CW, or ask by voice and give your call sign on phone.
Which of the following complies with commonly accepted amateur practice when choosing a frequency on which to initiate a call?
Answer C. Following the voluntary band plan is commonly accepted practice when choosing a frequency.
What is the voluntary band plan restriction for US stations transmitting within the 48 contiguous states in the 50.1 MHz to 50.125 MHz band segment?
Answer A. The band plan reserves 50.100 to 50.125 MHz for DX contacts. Stations in the 48 contiguous states should use it only for contacts outside the lower 48.
Who may be the control operator of an amateur station transmitting in RACES to assist relief operations during a disaster?
Answer A. Only a person holding an FCC-issued amateur operator license may be the control operator of a RACES station.
Which of the following is good amateur practice for net management?
Answer B. A backup frequency lets a net move if interference or poor conditions make the main frequency unusable.
How often may RACES training drills and tests be routinely conducted without special authorization?
Answer C. RACES training drills and tests may be routinely conducted for no more than 1 hour per week without special authorization.
Which of the following describes full break-in CW operation (QSK)?
Answer D. With full break-in (QSK), the transmitting station hears signals between code characters and elements, so the other station can interrupt at any time.
What should you do if a CW station sends “QRS?”
Answer A. QRS means "send more slowly."
What does it mean when a CW operator sends “KN” at the end of a transmission?
Answer C. KN at the end of a CW transmission means only the station(s) already in contact should reply.
What does the Q signal “QRL?” mean?
Answer D. QRL? asks "Are you busy?" or "Is this frequency in use?"
What is the best speed to use when answering a CQ in Morse code?
Answer B. Answer a CQ at the fastest speed you can comfortably copy, but no faster than the station calling CQ.
What does the term “zero beat” mean in CW operation?
Answer D. Zero beat means setting your transmit frequency to exactly match the received station's frequency.
When sending CW, what does a “C” mean when added to the RST report?
Answer A. A "C" after an RST report (for example 579C) indicates a chirpy or unstable signal.
What prosign is sent to indicate the end of a formal message when using CW?
Answer C. AR marks the end of a formal message on CW.
What does the Q signal “QSL” mean?
Answer C. QSL means "I have received and understood" (acknowledgment).
What does the Q signal “QRN” mean?
Answer D. QRN means "I am troubled by static" (natural noise).
What does the Q signal “QRV” mean?
Answer D. QRV means "I am ready to receive."
What is the Volunteer Monitor Program?
Answer A. The Volunteer Monitor Program uses amateur volunteers who are formally enlisted to monitor the airwaves for rules violations.
Which of the following are objectives of the Volunteer Monitor Program?
Answer D. Its goal is to encourage amateurs to self-regulate and comply with the rules.
What procedure may be used by Volunteer Monitors to localize a station whose continuous carrier is holding a repeater on in their area?
Answer B. Volunteer Monitors in different places take beam headings on the repeater's input frequency and compare them. Where the headings cross shows the transmitter's location.
Which of the following describes an azimuthal projection map?
Answer B. An azimuthal projection map is centered on one location and shows true bearings and distances from it, which makes it useful for aiming a beam antenna.
Which of the following indicates that you are looking for an HF contact with any station?
Answer C. To call any station on HF, repeat "CQ" a few times, say "this is," give your call sign a few times, then pause and listen.
How is a directional antenna pointed when making a “long-path” contact with another station?
Answer C. For a long-path contact, point the antenna 180 degrees from the short-path heading, the long way around the Earth.
Which of the following are examples of the NATO Phonetic Alphabet?
Answer D. The NATO (ITU) phonetic alphabet starts Alpha, Bravo, Charlie, Delta.
Why do many amateurs keep a station log?
Answer D. Logs are no longer required, but many amateurs keep them to help answer if the FCC asks about their station's operation.
Which of the following is required when participating in a contest on HF frequencies?
Answer C. During a contest you must still identify according to normal FCC rules. Logs and QSL cards are voluntary.
What is QRP operation?
Answer B. QRP means low-power operation, commonly 5 watts or less on CW.
Why are signal reports typically exchanged at the beginning of an HF contact?
Answer A. Early signal reports let both stations adjust to conditions, for example by repeating information or changing power.
Which mode is normally used when sending RTTY signals via AFSK with an SSB transmitter?
Answer D. When RTTY is sent with AFSK through an SSB transmitter, lower sideband is the convention.
What is VARA?
Answer B. VARA is a digital protocol used with the Winlink email system.
What symptoms may result from other signals interfering with a PACTOR or VARA transmission?
Answer D. Interference to PACTOR or VARA can cause frequent retries or timeouts, long pauses, or failure to connect. All are symptoms.
Which of the following is good practice when choosing a transmitting frequency to answer a station calling CQ using FT8?
Answer D. FT8 stations alternate 15-second time slots. Answer on a clear frequency in the time slot opposite the calling station, so you transmit while they listen.
What is the standard sideband for JT65, JT9, FT4, or FT8 digital signal when using AFSK?
Answer B. JT65, JT9, FT4 and FT8 are normally sent with upper sideband (USB).
What is the most common frequency shift for RTTY emissions in the amateur HF bands?
Answer B. The most common RTTY frequency shift on HF is 170 Hz.
Which of the following is required when using FT8?
Answer B. FT8 relies on precise timing, so your computer clock must be accurate to within about 1 second.
In what segment of the 20-meter band are most digital mode operations commonly found?
Answer D. On 20 meters, most digital-mode activity is between 14.070 and 14.100 MHz.
How do you join a contact between two stations using the PACTOR protocol?
Answer C. A PACTOR connection is limited to two stations, so you cannot join an existing contact.
Which of the following is a way to establish contact with a digital messaging system gateway station?
Answer D. To reach a digital messaging gateway, transmit a connect request on the gateway's published frequency.
What is the primary purpose of an Amateur Radio Emergency Data Network (AREDN) mesh network?
Answer C. AREDN mesh networks provide high-speed data services during emergencies or community events.
Which of the following describes Winlink?
Answer D. Winlink is a radio email network that works on both HF and VHF and can use packet radio. All of these describe it.
What is another name for a Winlink Remote Message Server?
Answer B. A Winlink Remote Message Server is also called a gateway.
What could be wrong if you cannot decode an RTTY or other FSK signal even though it is apparently tuned in properly?
Answer D. If an FSK signal won't decode even though it seems tuned in, the cause can be reversed mark and space, the wrong baud rate, or the wrong sideband. All are possible.
Which of the following is a common location for FT8?
Answer C. FT8 on 20 meters is found at about 14.074 to 14.077 MHz.
3 exam questions from this subelement. Practice G3 · Study notes
How does a higher sunspot number affect HF propagation?
Answer A. More sunspots mean more solar ultraviolet radiation and a more strongly ionized ionosphere. That generally improves propagation on the higher HF bands.
What effect does a sudden ionospheric disturbance have on the daytime ionospheric propagation?
Answer B. A sudden ionospheric disturbance (from a solar flare) increases D-region absorption on the daylight side of Earth. Lower frequencies are disrupted more than higher ones.
Approximately how long does it take the increased ultraviolet and X-ray radiation from a solar flare to affect radio propagation on Earth?
Answer C. Ultraviolet and X-ray radiation travel at the speed of light, so a flare's effects reach Earth in about 8 minutes.
Which of the following are the least reliable bands for long-distance communications during periods of low solar activity?
Answer D. With low solar activity, the ionosphere usually cannot support 15, 12 and 10 meters, so these bands are the least reliable for long-distance contacts.
What is the solar flux index?
Answer D. The solar flux index measures the Sun's radio emission at 10.7 cm wavelength (2800 MHz). Higher values generally mean better HF conditions.
What is a geomagnetic storm?
Answer D. A geomagnetic storm is a temporary disturbance of Earth's magnetic field, usually caused by solar particles.
At what point in the solar cycle does the 20-meter band usually support worldwide propagation during daylight hours?
Answer D. 20 meters usually supports daytime worldwide propagation at any point in the solar cycle, which makes it a reliable DX band.
How can a geomagnetic storm affect HF propagation?
Answer D. Geomagnetic storms especially degrade HF propagation along high-latitude (polar) paths.
How can high geomagnetic activity benefit radio communications?
Answer A. High geomagnetic activity creates auroras, which can reflect VHF signals for auroral contacts.
What causes HF propagation conditions to vary periodically in a 26- to 28-day cycle?
Answer C. The Sun rotates about every 27 days, bringing the same active regions back into view. This causes a 26- to 28-day cycle in conditions.
How long does it take a coronal mass ejection to affect radio propagation on Earth?
Answer D. Particles from a coronal mass ejection travel much slower than light, taking about 15 hours to several days to reach Earth.
What does the K-index measure?
Answer B. The K-index measures the short-term stability of Earth's geomagnetic field. Low values mean quiet conditions.
What does the A-index measure?
Answer C. The A-index measures the long-term (daily) stability of Earth's geomagnetic field.
How is long distance radio communication usually affected by the charged particles that reach Earth from solar coronal holes?
Answer B. Charged particles from coronal holes disturb Earth's magnetic field and degrade HF communication.
What is a characteristic of skywave signals arriving at your location by both short-path and long-path propagation?
Answer D. A signal arriving by both the short path and the long path travels different distances, so you may hear a slightly delayed echo.
What factors affect the MUF?
Answer D. The MUF depends on path distance and location, time of day and season, and solar radiation and disturbances. All of these.
Which frequency will have the least attenuation for long-distance skip propagation?
Answer A. Frequencies just below the MUF are refracted back to Earth with the least absorption, giving the best long-distance signals.
Which of the following is a way to determine current propagation on a desired band from your station?
Answer A. Automated receiving networks on the internet (such as reverse beacon or reporting networks) show where your signal is actually being heard.
How does the ionosphere affect radio waves with frequencies below the MUF and above the LUF?
Answer A. Frequencies between the LUF and the MUF are refracted back to Earth, so they are usable for skywave communication.
What usually happens to radio waves with frequencies below the LUF?
Answer C. Below the LUF, signals are absorbed (attenuated) before reaching their destination, mostly in the D region.
What does LUF stand for?
Answer A. LUF is the Lowest Usable Frequency for communication between two specific points.
What does MUF stand for?
Answer B. MUF is the Maximum Usable Frequency for communication between two points.
What is the approximate maximum distance along the Earth’s surface normally covered in one hop using the F2 region?
Answer C. One hop off the F2 region normally covers up to about 2,500 miles.
What is the approximate maximum distance along the Earth’s surface normally covered in one hop using the E region?
Answer B. The E region is lower than the F2 region, so one E-region hop covers up to about 1,200 miles.
What happens to HF propagation when the LUF exceeds the MUF?
Answer A. If the LUF rises above the MUF, no frequency works, so ordinary skywave communication over that path is not possible.
Which of the following is typical of the lower HF frequencies during the summer?
Answer D. In summer, thunderstorms produce high levels of static on the lower HF bands.
Which ionospheric region is closest to the surface of Earth?
Answer A. The D region is the lowest ionospheric region, closest to Earth's surface.
What is meant by the term “critical frequency” at a given incidence angle?
Answer A. The critical frequency is the highest frequency that will be refracted back to Earth at a given angle.
Why is skip propagation via the F2 region longer than that via the other ionospheric regions?
Answer C. The F2 region is the highest ionospheric layer, so signals refracted there come back to Earth farthest away.
What does the term “critical angle” mean, as applied to radio wave propagation?
Answer D. The critical angle is the highest takeoff angle at which a radio wave will still be returned to Earth. Waves sent at steeper angles pass through.
Why is long-distance communication on the 40-, 60-, 80-, and 160-meter bands more difficult during the day?
Answer C. During daylight, the D region absorbs signals on 160, 80, 60 and 40 meters, making long-distance daytime contacts difficult.
What is a characteristic of HF scatter?
Answer B. HF scatter signals have a characteristic fluttering sound.
What makes HF scatter signals often sound distorted?
Answer D. Scatter signals reach you by several different paths at once, which makes them sound distorted.
Why are HF scatter signals in the skip zone usually weak?
Answer A. Only a small part of the signal energy is scattered into the skip zone, so scatter signals there are weak.
What type of propagation allows signals to be heard in the transmitting station’s skip zone?
Answer B. Scatter propagation lets signals be heard inside the transmitting station's skip zone.
What is near vertical incidence skywave (NVIS) propagation?
Answer B. NVIS uses very high elevation angles so signals go almost straight up and come back down, giving reliable short-range MF/HF coverage.
Which ionospheric region is the most absorbent of signals below 10 MHz during daylight hours?
Answer D. In daytime, the D region absorbs signals below 10 MHz more than any other region.
5 exam questions from this subelement. Practice G4 · Study notes
What is the purpose of the notch filter found on many HF transceivers?
Answer B. A notch filter removes a narrow slice of the passband. That cuts out interfering carriers (steady tones) in the receiver passband.
What is the benefit of using the opposite or “reverse” sideband when receiving CW?
Answer C. Switching to the opposite sideband when receiving CW moves interfering signals to a different place in the passband. This can reduce or eliminate the interference.
How does a noise blanker work?
Answer C. A noise blanker reduces receiver gain during each short noise pulse, such as ignition noise, silencing the pulse.
What is the effect on plate current of the correct setting of a vacuum-tube RF power amplifier’s TUNE control?
Answer B. Correct tuning of a tube amplifier's TUNE control produces a pronounced dip in plate current.
Why is automatic level control (ALC) used with an RF power amplifier?
Answer C. ALC feedback from the amplifier reduces the drive from the transceiver, preventing excessive drive and distortion.
What is the purpose of an antenna tuner?
Answer C. An antenna tuner matches the transmitter to the feed line's impedance, increasing power transfer from the transmitter to the feed line. It does not change SWR on the feed line itself.
What happens as a receiver’s noise reduction control level is increased?
Answer A. Turning noise reduction up too high can distort received signals.
What is the correct adjustment for the LOAD or COUPLING control of a vacuum tube RF power amplifier?
Answer D. Adjust the LOAD (coupling) control for the desired power output without exceeding the maximum allowable plate current.
What is the purpose of delaying RF output after activating a transmitter’s keying line to an external amplifier?
Answer C. The delay gives the amplifier's relays time to switch the antenna before RF arrives, preventing hot-switching damage.
What is the function of an electronic keyer?
Answer B. An electronic keyer automatically generates correctly timed dots and dashes for CW.
Why should the ALC system be inactive when transmitting AFSK data signals?
Answer B. ALC action on data signals distorts them, so set the audio level so ALC stays inactive.
Which of the following is a common use of the dual-VFO feature on a transceiver?
Answer C. Dual VFOs let you transmit on one frequency and listen on another (split operation), common when working DX.
What is the purpose of using a receive attenuator?
Answer A. A receive attenuator reduces strong incoming signals to prevent receiver overload.
What item of test equipment contains horizontal and vertical channel amplifiers?
Answer D. An oscilloscope has horizontal and vertical channel amplifiers to display waveforms.
Which of the following is an advantage of an oscilloscope versus a digital voltmeter?
Answer D. An oscilloscope shows the shape of a signal, so it can measure complex waveforms. A digital voltmeter shows only a number.
Which of the following is the best instrument to use for checking the keying waveform of a CW transmitter?
Answer A. An oscilloscope shows the CW keying waveform, revealing problems such as key clicks from too-sharp keying.
What signal source is connected to the vertical input of an oscilloscope when checking the RF envelope pattern of a transmitted signal?
Answer D. To view the RF envelope pattern, connect the attenuated RF output of the transmitter to the scope's vertical input.
Why do voltmeters have high input impedance?
Answer D. A high input impedance draws very little current, which decreases loading on the circuit being measured and gives more accurate readings.
What is an advantage of a digital multimeter as compared to an analog multimeter?
Answer C. Digital multimeters generally offer higher precision than analog meters.
What signals are used to conduct a two-tone test?
Answer B. A two-tone test uses two audio tones that are not harmonically related.
What transmitter performance parameter does a two-tone test analyze?
Answer A. A two-tone test checks transmitter linearity.
When is an analog multimeter preferred to a digital multimeter?
Answer D. An analog meter's moving needle makes it easier to see a peak or dip when adjusting circuits for maximum or minimum values.
Which of the following can be determined with a directional wattmeter?
Answer A. A directional wattmeter measures forward and reflected power, from which SWR is determined.
Which of the following must be connected to an antenna analyzer when it is being used for SWR measurements?
Answer C. For SWR measurements, connect the antenna analyzer to the antenna and feed line.
What effect can strong signals from nearby transmitters have on an antenna analyzer?
Answer B. Strong signals from nearby transmitters can be picked up by the analyzer and disturb its SWR readings.
Which of the following can be measured with an antenna analyzer?
Answer C. An antenna analyzer can measure the impedance of coaxial cable.
Which of the following might be useful in reducing RF interference to audio frequency circuits?
Answer B. A bypass capacitor shunts RF to ground while letting audio pass, reducing RF interference in audio circuits.
Which of the following could be a cause of interference covering a wide range of frequencies?
Answer C. Arcing at a poor electrical connection creates broadband noise covering a wide range of frequencies.
What sound is heard from an audio device experiencing RF interference from a single sideband phone transmitter?
Answer C. RF interference from SSB phone sounds like distorted speech in audio equipment.
What sound is heard from an audio device experiencing RF interference from a CW transmitter?
Answer A. RF interference from a CW transmitter sounds like on-and-off humming or clicking.
What is a possible cause of high voltages that produce RF burns?
Answer D. A ground wire with high impedance at the operating frequency can develop high RF voltages, which can cause RF burns.
What is a possible effect of a resonant ground connection?
Answer C. A resonant ground connection can put high RF voltages on equipment enclosures.
Why should soldered joints not be used in lightning protection ground connections?
Answer A. A lightning strike's heat can melt solder and destroy the joint, so use mechanical connections or welding for lightning grounds.
Which of the following would reduce RF interference caused by common-mode current on an audio cable?
Answer A. A ferrite choke on the cable blocks common-mode RF current, reducing interference.
How can the effects of ground loops be minimized?
Answer D. Bonding equipment enclosures together keeps them at the same potential and minimizes ground loops.
What could be a symptom caused by a ground loop in your station’s audio connections?
Answer A. A ground loop in audio connections commonly causes reports of hum on your transmitted signal.
What technique helps to minimize RF “hot spots” in an amateur station?
Answer C. Bonding all equipment enclosures together minimizes RF "hot spots" in the station.
Why must all metal enclosures of station equipment be grounded?
Answer D. Grounding metal enclosures ensures hazardous voltages cannot appear on the chassis, for example if there is an internal fault.
What is the purpose of a speech processor in a transceiver?
Answer A. A speech processor increases the apparent loudness of your transmitted voice.
How does a speech processor affect a single sideband phone signal?
Answer B. Speech processing raises the average power of an SSB signal relative to its peaks. It does not raise peak power.
What is the effect of an incorrectly adjusted speech processor?
Answer D. A misadjusted speech processor can cause distorted speech, excess intermodulation products and excessive background noise.
What does an S meter measure?
Answer C. An S meter measures received signal strength.
How does a signal that reads 20 dB over S9 compare to one that reads S9 on a receiver, assuming a properly calibrated S meter?
Answer D. 20 dB is a power ratio of 100, so 20 dB over S9 is 100 times more powerful than S9.
How much change in signal strength is typically represented by one S unit?
Answer A. One S unit is typically 6 dB.
How much must the power output of a transmitter be raised to change the S meter reading on a distant receiver from S8 to S9?
Answer C. One S unit is 6 dB, which is about 4 times the power.
What frequency range is occupied by a 3 kHz LSB signal when the displayed carrier frequency is set to 7.178 MHz?
Answer C. LSB occupies frequencies below the displayed carrier. A 3 kHz LSB signal at 7.178 MHz occupies 7.175 to 7.178 MHz.
What frequency range is occupied by a 3 kHz USB signal with the displayed carrier frequency set to 14.347 MHz?
Answer B. USB occupies frequencies above the displayed carrier. A 3 kHz USB signal at 14.347 MHz occupies 14.347 to 14.350 MHz.
How close to the lower edge of a band’s phone segment should your displayed carrier frequency be when using 3 kHz wide LSB?
Answer A. LSB extends 3 kHz below the displayed frequency, so set it at least 3 kHz above the segment's lower edge.
How close to the upper edge of a band’s phone segment should your displayed carrier frequency be when using 3 kHz wide USB?
Answer B. USB extends 3 kHz above the displayed frequency, so set it at least 3 kHz below the upper band edge.
What is the purpose of a capacitance hat on a mobile antenna?
Answer C. A capacitance hat electrically lengthens a physically short antenna.
What is the purpose of a corona ball on an HF mobile antenna?
Answer D. A corona ball on the antenna tip reduces RF voltage discharge (corona) from the tip while transmitting.
Which of the following direct, fused power connections would be the best for a 100-watt HF mobile installation?
Answer A. Connect a 100-watt HF mobile radio directly to the battery with heavy-gauge, fused wire.
Why should DC power for a 100-watt HF transceiver not be supplied by a vehicle’s auxiliary power socket?
Answer B. Accessory socket wiring is often too light for the current a 100-watt transceiver draws.
Which of the following most limits an HF mobile installation?
Answer C. The efficiency of the electrically short antenna is the biggest limitation on HF mobile performance.
What is one disadvantage of using a shortened mobile antenna as opposed to a full-size antenna?
Answer C. Shortened mobile antennas often have a very narrow operating bandwidth.
Which of the following may cause receive interference to an HF transceiver installed in a vehicle?
Answer D. A vehicle's charging system, fuel delivery system and control computers can all cause receive interference.
In what configuration are the individual cells in a solar panel connected together?
Answer A. Solar cells are connected in series-parallel: series for voltage, parallel for current.
What is the approximate open-circuit voltage from a fully illuminated silicon photovoltaic cell?
Answer B. A fully illuminated silicon solar cell produces about 0.5 volts open-circuit.
Why should a series diode be connected between a solar panel and a storage battery that is being charged by the panel?
Answer B. The series diode prevents the battery from discharging back through the panel when there is little or no light.
What precaution should be taken when connecting a solar panel to a lithium iron phosphate battery?
Answer D. A lithium iron phosphate (LiFePO4) battery must be charged through a proper charge controller.
3 exam questions from this subelement. Practice G5 · Study notes
What happens when inductive and capacitive reactance are equal in a series LC circuit?
Answer C. In a series LC circuit at resonance, the reactances cancel, so impedance is very low (just the resistance).
What is reactance?
Answer B. Reactance is opposition to alternating current caused by capacitance or inductance.
Which of the following is opposition to the flow of alternating current in an inductor?
Answer D. An inductor's opposition to AC is called (inductive) reactance.
Which of the following is opposition to the flow of alternating current in a capacitor?
Answer C. A capacitor's opposition to AC is called (capacitive) reactance.
How does an inductor react to AC?
Answer D. Inductive reactance increases as frequency increases (XL = 2πfL).
How does a capacitor react to AC?
Answer A. Capacitive reactance decreases as frequency increases (XC = 1 / 2πfC).
What is the term for the inverse of impedance?
Answer D. Admittance is the inverse of impedance.
What is impedance?
Answer C. Impedance is the ratio of voltage to current (Z = E / I).
What unit is used to measure reactance?
Answer B. Reactance, like resistance, is measured in ohms.
Which of the following devices can be used for impedance matching at radio frequencies?
Answer D. Transformers, pi-networks and lengths of transmission line can all match impedances at RF.
What letter is used to represent reactance?
Answer B. Reactance is represented by the letter X.
What occurs in an LC circuit at resonance?
Answer D. At resonance, inductive and capacitive reactance are equal and cancel each other.
What dB change represents a factor of two increase or decrease in power?
Answer B. A factor of two in power is about 3 dB.
How does the total current relate to the individual currents in a circuit of parallel resistors?
Answer C. In a parallel circuit, the total current equals the sum of the branch currents.
How many watts of electrical power are consumed if 400 VDC is supplied to an 800-ohm load?
Answer B. P = E² / R = 400² / 800 = 160,000 / 800 = 200 watts.
How many watts of electrical power are consumed by a 12 VDC light bulb that draws 0.2 amperes?
Answer A. P = E x I = 12 V x 0.2 A = 2.4 watts.
How many watts are consumed when a current of 7.0 milliamperes flows through a 1,250-ohm resistance?
Answer A. P = I² x R = (0.007 A)² x 1250 ohms = 0.061 W, about 61 milliwatts.
What is the PEP produced by 200 volts peak-to-peak across a 50-ohm dummy load?
Answer B. 200 V peak-to-peak is 100 V peak, or 70.7 V RMS. PEP = 70.7² / 50 = 100 watts.
What value of an AC signal produces the same power dissipation in a resistor as a DC voltage of the same value?
Answer C. The RMS value of AC produces the same heating in a resistor as the same DC voltage.
What is the peak-to-peak voltage of a sine wave with an RMS voltage of 120 volts?
Answer D. Peak = 120 x 1.414 = 169.7 V. Peak-to-peak is twice that: 339.4 V.
What is the RMS voltage of a sine wave with a value of 17 volts peak?
Answer B. RMS = peak x 0.707 = 17 x 0.707, about 12 volts.
What percentage of power loss is equivalent to a loss of 1 dB?
Answer C. A 1 dB loss leaves 10^(-0.1), or about 79.4%, of the power. That is a loss of about 20.6%.
What is the ratio of PEP to average power for an unmodulated carrier?
Answer B. An unmodulated carrier has constant amplitude, so PEP equals average power: a ratio of 1.00.
What is the RMS voltage across a 50-ohm dummy load dissipating 1200 watts?
Answer B. E = √(P x R) = √(1200 x 50) = √60,000, about 245 volts RMS.
What is the output PEP of an unmodulated carrier if the average power is 1060 watts?
Answer B. For an unmodulated carrier, PEP equals average power: 1060 watts.
What is the output PEP of 500 volts peak-to-peak across a 50-ohm load?
Answer B. 500 V peak-to-peak is 250 V peak, or 176.8 V RMS. PEP = 176.8² / 50, about 625 watts.
What causes a voltage to appear across the secondary winding of a transformer when an AC voltage source is connected across its primary winding?
Answer C. Mutual inductance couples the changing magnetic field of the primary into the secondary, inducing a voltage.
What is the output voltage if an input signal is applied to the secondary winding of a 4:1 voltage step-down transformer instead of the primary winding?
Answer A. Driving a 4:1 step-down transformer backwards makes it a 1:4 step-up transformer, so the input voltage is multiplied by 4.
What is the total resistance of a 10-, a 20-, and a 50-ohm resistor connected in parallel?
Answer A. 1/R = 1/10 + 1/20 + 1/50 = 0.1 + 0.05 + 0.02 = 0.17, so R = 1 / 0.17, about 5.9 ohms.
What is the approximate total resistance of a 100- and a 200-ohm resistor in parallel?
Answer D. Two parallel resistors: R = (100 x 200) / (100 + 200) = 20,000 / 300, about 67 ohms.
Why is the primary winding wire of a voltage step-up transformer usually a larger size than that of the secondary winding?
Answer B. In a step-up transformer the primary carries more current than the secondary, so it uses heavier wire.
What is the voltage output of a transformer with a 500-turn primary and a 1500-turn secondary when 120 VAC is applied to the primary?
Answer A. The voltage ratio equals the turns ratio: 1500 / 500 = 3, so 120 V x 3 = 360 volts.
What transformer turns ratio matches an antenna’s 600-ohm feed point impedance to a 50-ohm coaxial cable?
Answer A. The turns ratio is the square root of the impedance ratio: √(600 / 50) = √12, about 3.5 to 1.
What is the equivalent capacitance of two 5.0-nanofarad capacitors and one 750-picofarad capacitor connected in parallel?
Answer D. Parallel capacitances add: 5.0 nF + 5.0 nF + 0.75 nF = 10.75 nF.
What is the capacitance of three 100-microfarad capacitors connected in series?
Answer C. Equal capacitors in series: divide by the number of capacitors. 100 µF / 3 = 33.3 µF.
What is the inductance of three 10-millihenry inductors connected in parallel?
Answer C. Equal inductors in parallel: divide by the number of inductors. 10 mH / 3 = 3.3 mH.
What is the inductance of a circuit with a 20-millihenry inductor connected in series with a 50-millihenry inductor?
Answer C. Series inductances add: 20 mH + 50 mH = 70 mH.
What is the capacitance of a 20-microfarad capacitor connected in series with a 50-microfarad capacitor?
Answer B. Capacitors in series: (20 x 50) / (20 + 50) = 1000 / 70, about 14.3 µF.
Which of the following components should be added to a capacitor to increase the capacitance?
Answer C. Adding a capacitor in parallel increases total capacitance.
Which of the following components should be added to an inductor to increase the inductance?
Answer D. Adding an inductor in series increases total inductance.
2 exam questions from this subelement. Practice G6 · Study notes
What is the minimum allowable discharge voltage for maximum life of a standard 12-volt lead-acid battery?
Answer C. For maximum life, a 12-volt lead-acid battery should not be discharged below about 10.5 volts.
What is an advantage of batteries with low internal resistance?
Answer B. Low internal resistance lets a battery deliver high discharge current without a large voltage drop.
What is the approximate forward threshold voltage of a germanium diode?
Answer B. A germanium diode starts conducting at about 0.3 volts forward bias.
Which of the following is characteristic of an electrolytic capacitor?
Answer C. Electrolytic capacitors offer high capacitance in a small volume. Their tolerance is loose and leakage is relatively high.
What is the approximate forward threshold voltage of a silicon junction diode?
Answer C. A silicon junction diode starts conducting at about 0.7 volts forward bias.
Why should wire-wound resistors not be used in RF circuits?
Answer B. A wire-wound resistor is a coil of wire, so it has inductance. At RF that inductance makes circuit behavior unpredictable.
What are the operating points for a bipolar transistor used as a switch?
Answer A. A transistor used as a switch operates at cutoff (off) and saturation (fully on).
Which of the following is characteristic of low voltage ceramic capacitors?
Answer D. Low-voltage ceramic capacitors are popular mainly because they are comparatively inexpensive.
Which of the following describes MOSFET construction?
Answer B. In a MOSFET, the gate is separated from the channel by a thin insulating (oxide) layer.
Which element of a vacuum tube regulates the flow of electrons between cathode and plate?
Answer A. The control grid regulates electron flow between the cathode and the plate in a vacuum tube.
What happens when an inductor is operated above its self-resonant frequency?
Answer C. Above its self-resonant frequency, an inductor's stray capacitance dominates and it behaves like a capacitor.
What is the primary purpose of a screen grid in a vacuum tube?
Answer A. A screen grid reduces the capacitance between the control grid and the plate, improving stability.
What determines the performance of a ferrite core at different frequencies?
Answer C. A ferrite core's performance at different frequencies depends on its material composition, called its "mix."
What is meant by the term MMIC?
Answer B. MMIC stands for Monolithic Microwave Integrated Circuit.
Which of the following is an advantage of CMOS integrated circuits compared to TTL integrated circuits?
Answer A. CMOS integrated circuits use very little power compared to TTL.
What is a typical upper frequency limit for low SWR operation of 50-ohm BNC connectors?
Answer C. Standard 50-ohm BNC connectors work with low SWR up to about 4 GHz.
What is an advantage of using a ferrite core toroidal inductor?
Answer D. Ferrite toroids give large inductance values, cores chosen for a specific frequency range, and a magnetic field mostly contained in the core. All are advantages.
What kind of device is an integrated circuit operational amplifier?
Answer D. An operational amplifier (op-amp) is an analog device.
Which of the following describes a type N connector?
Answer A. Type N connectors are moisture-resistant RF connectors usable to about 10 GHz.
How is an LED biased when emitting light?
Answer D. An LED emits light when it is forward biased.
How does a ferrite bead or core reduce common-mode RF current on the shield of a coaxial cable?
Answer A. A ferrite bead or core adds impedance to the common-mode current path on the outside of the coax shield, choking it off.
What is an SMA connector?
Answer B. An SMA connector is a small threaded connector suitable for signals up to several GHz.
Which of these connector types is commonly used for low frequency or dc signal connections to a transceiver?
Answer C. RCA phono connectors are common for low-frequency and DC connections, such as audio and keying lines.
3 exam questions from this subelement. Practice G7 · Study notes
What is the function of a power supply bleeder resistor?
Answer B. A bleeder resistor discharges the filter capacitors after power is removed, reducing shock hazard.
Which of the following components are used in a power supply filter network?
Answer C. Power supply filters use capacitors and inductors to smooth the rectified DC.
Which type of rectifier circuit uses two diodes and a center-tapped transformer?
Answer A. A full-wave rectifier can use two diodes with a center-tapped transformer. A bridge uses four diodes and no center tap.
What is characteristic of a half-wave rectifier in a power supply?
Answer A. A half-wave rectifier needs only one diode.
What portion of the AC cycle is converted to DC by a half-wave rectifier?
Answer B. A half-wave rectifier converts only half of the AC cycle, 180 degrees.
What portion of the AC cycle is converted to DC by a full-wave rectifier?
Answer D. A full-wave rectifier converts the whole AC cycle, 360 degrees.
What is the output waveform of an unfiltered full-wave rectifier connected to a resistive load?
Answer A. Unfiltered full-wave output is a series of DC pulses at twice the AC input frequency (120 Hz from 60 Hz mains).
Which of the following is characteristic of a switchmode power supply as compared to a linear power supply?
Answer C. Switchmode supplies operate at high frequency, allowing much smaller and lighter transformers and filter components.
Which symbol in figure G7-1 represents a field effect transistor?
Answer C. Symbol 1 in figure G7-1 is a field-effect transistor (FET).
Which symbol in figure G7-1 represents a Zener diode?
Answer D. Symbol 5 in figure G7-1 is a Zener diode, shown by the bent bar on the diode symbol.
Which symbol in figure G7-1 represents an NPN junction transistor?
Answer B. Symbol 2 in figure G7-1 is an NPN bipolar junction transistor, with the emitter arrow pointing out.
Which symbol in Figure G7-1 represents a solid core transformer?
Answer C. Symbol 6 in figure G7-1 is a transformer with a solid core, shown by the lines between the windings.
Which symbol in Figure G7-1 represents a tapped inductor?
Answer A. Symbol 7 in figure G7-1 is an inductor with a connection partway along the coil: a tapped inductor.
What is the purpose of neutralizing an amplifier?
Answer B. Neutralizing an amplifier cancels unwanted feedback to eliminate self-oscillation.
Which of these classes of amplifiers has the highest efficiency?
Answer D. Class C amplifiers conduct for less than half the cycle and have the highest efficiency of these classes.
Which of the following describes the function of a two-input AND gate?
Answer B. A two-input AND gate's output is high only when both inputs are high.
In a Class A amplifier, what percentage of the time does the amplifying device conduct?
Answer A. A Class A amplifier conducts 100% of the time.
How many states does a 3-bit binary counter have?
Answer C. A 3-bit counter has 2³ = 8 states (0 through 7).
What is a shift register?
Answer A. A shift register is a clocked array of circuits that moves data one step along the array with each clock pulse.
Which of the following are basic components of a sine wave oscillator?
Answer D. A sine wave oscillator is an amplifier and a frequency-selective filter connected in a positive feedback loop.
How is the efficiency of an RF power amplifier determined?
Answer B. Amplifier efficiency is RF output power divided by DC input power.
What determines the frequency of an LC oscillator?
Answer C. An LC oscillator's frequency is set by the inductance and capacitance in its tank circuit.
Which of the following describes a linear amplifier?
Answer B. A linear amplifier's output preserves the shape of the input waveform. SSB requires this.
For which of the following modes is a Class C power stage appropriate for amplifying a modulated signal?
Answer B. FM has constant amplitude, so an efficient non-linear Class C amplifier can be used. SSB and AM need linear amplification.
What circuit is used to select one of the sidebands from a balanced modulator?
Answer B. A filter selects one sideband from the double-sideband output of a balanced modulator.
What output is produced by a balanced modulator?
Answer D. A balanced modulator produces double-sideband RF with the carrier suppressed.
What is one reason to use an impedance matching transformer at a transmitter output?
Answer B. An impedance matching transformer presents the desired impedance to both the transmitter and the feed line.
How is a product detector used?
Answer D. A product detector recovers the audio (modulation) from an SSB signal in a receiver.
Which of the following is characteristic of a direct digital synthesizer (DDS)?
Answer D. A DDS generates a variable output frequency with the stability of its crystal reference oscillator.
Which of the following is an advantage of a digital signal processing (DSP) filter compared to an analog filter?
Answer A. DSP filters can be configured for a wide range of bandwidths and shapes in software.
What term specifies a filter’s attenuation inside its passband?
Answer A. Insertion loss is a filter's attenuation within its passband.
Which parameter affects receiver sensitivity?
Answer D. Receiver sensitivity is affected by input amplifier gain, demodulator bandwidth and input amplifier noise figure. All three.
What is the phase difference between the I and Q RF signals that software-defined radio (SDR) equipment uses for modulation and demodulation?
Answer B. I (in-phase) and Q (quadrature) signals are 90 degrees apart.
What is an advantage of using I-Q modulation with software-defined radios (SDRs)?
Answer B. With I-Q processing, an SDR can create any type of modulation in software.
Which of these functions is performed by software in a software-defined radio (SDR)?
Answer D. In an SDR, filtering, detection and modulation are all done in software.
What is the frequency above which a low-pass filter’s output power is less than half the input power?
Answer C. The cutoff frequency of a low-pass filter is where output drops to half power (-3 dB).
What term specifies a filter’s maximum ability to reject signals outside its passband?
Answer D. Ultimate rejection is a filter's maximum ability to reject signals outside its passband.
The bandwidth of a band-pass filter is measured between what two frequencies?
Answer A. A band-pass filter's bandwidth is measured between the upper and lower half-power (-3 dB) points.
3 exam questions from this subelement. Practice G8 · Study notes
How is direct binary FSK modulation generated?
Answer B. Direct FSK is generated by shifting an oscillator's frequency directly with a digital control signal.
What is the name of the process that changes the phase angle of an RF signal to convey information?
Answer B. Phase modulation changes the phase angle of the RF signal to carry information.
What is the name of the process that changes the instantaneous frequency of an RF wave to convey information?
Answer D. Frequency modulation changes the instantaneous frequency of the RF wave to carry information.
What emission is produced by a reactance modulator connected to a transmitter RF amplifier stage?
Answer B. A reactance modulator on an RF amplifier stage produces phase modulation.
What type of modulation varies the instantaneous power level of the RF signal?
Answer D. Amplitude modulation varies the RF signal's instantaneous power (amplitude).
Which of the following is characteristic of QPSK31?
Answer D. QPSK31 is sideband sensitive, includes error-correcting encoding, and uses about the same bandwidth as BPSK31.
Which of the following phone emissions uses the narrowest bandwidth?
Answer A. Single sideband uses the narrowest bandwidth of these phone emissions.
Which of the following is an effect of overmodulation?
Answer D. Overmodulation creates distortion products that spread the signal over excessive bandwidth (splatter).
What type of modulation is used by FT8?
Answer A. FT8 uses 8-tone frequency shift keying (8-FSK).
What is meant by the term “flat-topping,” when referring to an amplitude-modulated phone signal?
Answer C. Flat-topping is distortion from excessive drive or speech levels: the signal peaks are clipped flat.
What is the modulation envelope of an AM signal?
Answer A. The modulation envelope is the waveform traced by connecting the peaks of the modulated signal.
What is QPSK modulation?
Answer D. QPSK uses four phase shifts (0, 90, 180 and 270 degrees), each representing a pair of bits.
What is a link budget?
Answer C. A link budget is transmit power plus antenna gains, minus all system losses, as seen at the receiver.
What is link margin?
Answer B. Link margin is how much the received signal exceeds the minimum level the receiver needs.
Which mixer input is varied or tuned to convert signals of different frequencies to an intermediate frequency (IF)?
Answer B. The local oscillator is tuned to convert different incoming frequencies to the same intermediate frequency.
What is the term for interference from a signal at twice the IF frequency from the desired signal?
Answer B. Image response is interference from a signal twice the IF away from the desired signal, on the other side of the local oscillator.
What is another term for the mixing of two RF signals?
Answer A. Mixing two RF signals is called heterodyning.
What is the stage in a VHF FM transmitter that generates a harmonic of a lower frequency signal to reach the desired operating frequency?
Answer D. A multiplier stage generates a harmonic of a lower-frequency signal to reach the operating frequency.
Which intermodulation products are closest to the original signal frequencies?
Answer C. Odd-order intermodulation products (such as 2F1 - F2) fall closest to the original signal frequencies.
What is the total bandwidth of an FM phone transmission having 5 kHz deviation and 3 kHz modulating frequency?
Answer D. By Carson's rule, FM bandwidth is about 2 x (deviation + modulating frequency) = 2 x (5 + 3) = 16 kHz.
What is the frequency deviation for a 12.21 MHz reactance modulated oscillator in a 5 kHz deviation, 146.52 MHz FM phone transmitter?
Answer B. The multiplication factor is 146.52 / 12.21 = 12, so the oscillator's deviation is 5 kHz / 12, about 416.7 Hz.
Why is it important to know the duty cycle of the mode you are using when transmitting?
Answer B. High duty cycle modes (such as FT8 or RTTY) transmit continuously and could exceed the transmitter's average power rating.
Why is it good to match receiver bandwidth to the bandwidth of the operating mode?
Answer D. Matching receiver bandwidth to the signal's bandwidth rejects extra noise and gives the best signal-to-noise ratio.
What is the relationship between transmitted symbol rate and bandwidth?
Answer B. Higher symbol rates require wider bandwidth.
What combination of a mixer’s Local Oscillator (LO) and RF input frequencies is found in the output?
Answer C. A mixer's output contains the sum and difference of the LO and RF input frequencies.
What process combines two signals in a non-linear circuit to produce unwanted spurious outputs?
Answer A. Intermodulation is the mixing of two signals in a non-linear circuit, producing unwanted spurious outputs.
Which of the following is an odd-order intermodulation product of frequencies F1 and F2?
Answer C. 2F1 - F2 is a third-order (odd-order) product because 2 + 1 = 3.
Which digital mode is used as a low-power beacon for assessing HF propagation?
Answer A. WSPR is a low-power beacon mode for assessing HF propagation.
What part of a packet radio frame contains the routing and handling information?
Answer C. The header of a packet frame carries the routing and handling information.
Which of the following describes Baudot code?
Answer C. Baudot is a 5-bit code with additional start and stop bits, used for RTTY.
In an ARQ mode, what is meant by a NAK response to a transmitted packet?
Answer A. NAK (negative acknowledgment) requests that the packet be retransmitted.
What action results from a failure to exchange information due to excessive transmission attempts when using an ARQ mode?
Answer B. If too many retries fail, the ARQ connection is dropped.
Which of the following narrow-band digital modes can receive signals with very low signal-to-noise ratios?
Answer B. FT8 can decode signals with very low signal-to-noise ratios.
Which of the following statements is true about PSK31?
Answer B. PSK31's Varicode gives common lowercase letters short codes. Uppercase letters use longer codes, so they slow transmission.
Which is true of mesh network microwave nodes?
Answer B. Mesh networks route around failures: if one node fails, packets may still reach their target by another node.
How does forward error correction (FEC) allow the receiver to correct data errors?
Answer C. FEC sends redundant information with the data so the receiver can correct errors without asking for a retransmission.
How are the two separate frequencies of a Frequency Shift Keyed (FSK) signal identified?
Answer D. The two FSK frequencies are called mark and space.
Which type of code is used for sending characters in a PSK31 signal?
Answer A. PSK31 sends characters using Varicode.
What is indicated on a waterfall display by one or more vertical lines on either side of a data mode or RTTY signal?
Answer D. Vertical lines on either side of a data or RTTY signal on a waterfall indicate overmodulation.
Which of the following describes a waterfall display?
Answer C. On a waterfall, frequency runs horizontally, time runs vertically, and signal strength is shown as intensity or color.
What does an FT8 signal report of +3 mean?
Answer C. FT8 reports are signal-to-noise ratio in a 2.5 kHz bandwidth, so +3 means +3 dB.
Which of the following provide digital voice modes?
Answer D. DMR, D-STAR and System Fusion are digital voice modes.
4 exam questions from this subelement. Practice G9 · Study notes
Which of the following factors determine the characteristic impedance of a parallel conductor feed line?
Answer A. The characteristic impedance of a parallel-conductor line depends on the spacing between conductor centers and the conductor radius.
What is the relationship between high standing wave ratio (SWR) and transmission line loss?
Answer B. High SWR increases loss in a lossy line, because reflected power travels the line repeatedly and loses some each pass.
What is the nominal characteristic impedance of “window line” transmission line?
Answer D. Window line has a nominal characteristic impedance of about 450 ohms.
What causes reflected power at an antenna’s feed point?
Answer C. Reflected power is caused by a mismatch between the feed line impedance and the antenna feed point impedance.
How does the attenuation of coaxial cable change with increasing frequency?
Answer B. Coax attenuation increases as frequency increases.
In what units is RF feed line loss usually expressed?
Answer D. Feed line loss is usually given in decibels per 100 feet.
What must be done to prevent standing waves on a feed line connected to an antenna?
Answer D. Standing waves are prevented when the antenna feed point impedance matches the feed line's characteristic impedance.
If the SWR on an antenna feed line is 5:1, and a matching network at the transmitter end of the feed line is adjusted to present a 1:1 SWR to the transmitter, what is the resulting SWR on the feed line?
Answer B. A tuner at the transmitter end only changes what the transmitter sees. The feed line itself still has a 5:1 SWR.
What standing wave ratio results from connecting a 50-ohm feed line to a 200-ohm resistive load?
Answer A. SWR = larger impedance / smaller impedance = 200 / 50 = 4:1.
What standing wave ratio results from connecting a 50-ohm feed line to a 10-ohm resistive load?
Answer D. SWR = 50 / 10 = 5:1.
What is the effect of transmission line loss on SWR measured at the input to the line?
Answer A. Line loss attenuates the reflected power before it gets back to the meter, so a lossy line makes the SWR measured at the input look lower than it really is.
What is a characteristic of a random-wire HF antenna connected directly to the transmitter?
Answer B. A random wire connected directly to the transmitter makes the station equipment part of the antenna system, so it may carry significant RF current.
Which of the following is a common way to adjust the feed point impedance of an elevated quarter-wave ground-plane vertical antenna to be approximately 50 ohms?
Answer B. Sloping the radials of an elevated ground-plane downward raises its feed point impedance toward 50 ohms.
Which of the following best describes the radiation pattern of a quarter-wave ground-plane vertical antenna?
Answer D. A quarter-wave ground-plane vertical radiates equally in all horizontal directions: omnidirectional in azimuth.
What is the radiation pattern of a dipole antenna in free space in a plane containing the conductor?
Answer A. In free space, a dipole's pattern in the plane of the wire is a figure-eight, strongest at right angles to the antenna.
How does antenna height affect the azimuthal radiation pattern of a horizontal dipole HF antenna at elevation angles higher than about 45 degrees?
Answer C. Below 1/2 wavelength high, a dipole's high-angle radiation is almost omnidirectional in azimuth.
Where should the radial wires of a ground-mounted vertical antenna system be placed?
Answer C. Radials for a ground-mounted vertical go on the surface or are buried a few inches below.
How does the feed point impedance of a horizontal 1/2 wave dipole antenna change as the antenna height is reduced to 1/10 wavelength above ground?
Answer B. As a horizontal dipole is lowered toward 1/10 wavelength above ground, its feed point impedance steadily decreases.
How does the feed point impedance of a 1/2 wave dipole change as the feed point is moved from the center toward the ends?
Answer A. Moving a dipole's feed point from the center toward the ends steadily increases the feed point impedance.
Which of the following is an advantage of using a horizontally polarized as compared to a vertically polarized HF antenna?
Answer A. Horizontally polarized HF antennas have lower ground losses than verticals.
What is the approximate length for a 1/2 wave dipole antenna cut for 14.250 MHz?
Answer D. Half-wave dipole length in feet is about 468 / MHz = 468 / 14.25, about 33 feet.
What is the approximate length for a 1/2 wave dipole antenna cut for 3.550 MHz?
Answer C. 468 / 3.55 MHz, about 132 feet.
What is the approximate length for a 1/4 wave monopole antenna cut for 28.5 MHz?
Answer A. Quarter-wave length in feet is about 234 / MHz = 234 / 28.5, about 8.2 feet.
Which of the following would increase the bandwidth of a Yagi antenna?
Answer A. Larger-diameter elements increase a Yagi's bandwidth.
What is the approximate length of the driven element of a Yagi antenna?
Answer B. A Yagi's driven element is about 1/2 wavelength long.
How do the lengths of a three-element Yagi reflector and director compare to that of the driven element?
Answer A. In a Yagi, the reflector is longer than the driven element and the director is shorter.
How does antenna gain in dBi compare to gain stated in dBd for the same antenna?
Answer B. dBi is relative to an isotropic radiator and dBd to a dipole, which has 2.15 dBi gain. So the dBi figure is 2.15 dB higher.
What is the primary effect of increasing boom length and adding directors to a Yagi antenna?
Answer A. A longer boom with more directors increases gain.
What does “front-to-back ratio” mean in reference to a Yagi antenna?
Answer C. Front-to-back ratio compares the power in the main lobe to the power radiated in the opposite direction.
What is meant by the “main lobe” of a directive antenna?
Answer D. The main lobe is the direction of maximum radiated field strength.
In free space, how does the gain of two three-element, horizontally polarized Yagi antennas spaced vertically 1/2 wavelength apart typically compare to the gain of a single three-element Yagi?
Answer B. Stacking two identical Yagis properly roughly doubles the gain, about 3 dB more than one.
Which of the following can be adjusted to optimize forward gain, front-to-back ratio, or SWR bandwidth of a Yagi antenna?
Answer D. Boom length, number of elements and element spacing can all be adjusted to optimize a Yagi.
What is a beta or hairpin match?
Answer A. A beta (hairpin) match is a shorted transmission-line stub at the Yagi feed point, used for impedance matching.
Which of the following is a characteristic of using a gamma match with a Yagi antenna?
Answer A. A gamma match lets the driven element connect directly to the boom without insulation.
Which of the following antenna types will be most effective as a near vertical incidence skywave (NVIS) antenna for short-skip communications on 40 meters during the day?
Answer A. For daytime 40-meter NVIS, use a horizontal dipole low over the ground, between 1/10 and 1/4 wavelength high, to send energy nearly straight up.
What is the feed point impedance of an end-fed half-wave antenna?
Answer D. An end-fed half-wave antenna has a very high feed point impedance and usually needs a matching transformer.
In which direction is the maximum radiation from a VHF/UHF “halo” antenna?
Answer C. A halo antenna radiates omnidirectionally in the plane of the halo (horizontally).
What is the primary function of antenna traps?
Answer A. Traps let one antenna operate on several bands (multiband operation).
What is an advantage of vertically stacking horizontally polarized Yagi antennas?
Answer D. Stacking horizontally polarized Yagis vertically narrows the main lobe in elevation, concentrating energy at lower angles.
Which of the following is an advantage of a log-periodic antenna?
Answer A. A log-periodic antenna's main advantage is very wide bandwidth.
Which of the following describes a log-periodic antenna?
Answer A. In a log-periodic antenna, element length and spacing vary logarithmically along the boom.
How does a “screwdriver” mobile antenna adjust its feed point impedance?
Answer B. A screwdriver antenna adjusts by changing its base loading inductance with a motor.
What is the primary use of a Beverage antenna?
Answer A. A Beverage is a long, low wire used for directional receiving on MF and low HF bands.
In which direction or directions does an electrically small loop (less than 1/10 wavelength in circumference) have nulls in its radiation pattern?
Answer B. A small loop has nulls broadside to the loop (perpendicular to its plane), which makes it useful for direction finding.
Which of the following is a disadvantage of multiband antennas?
Answer D. Multiband antennas resonate on several frequencies, so they have poor harmonic rejection.
What is the common name of a dipole with a single central support?
Answer A. A dipole hung from one central support with its ends sloping down is called an inverted V.
2 exam questions from this subelement. Practice G0 · Study notes
What is one way that RF energy can affect human body tissue?
Answer A. RF energy affects the body mainly by heating tissue.
Which of the following is used to determine RF exposure from a transmitted signal?
Answer D. RF exposure depends on duty cycle, frequency and power density. All are used to determine it.
How can you determine that your station complies with FCC RF exposure regulations?
Answer D. Compliance can be shown by calculation (OET Bulletin 65), by computer modeling, or by measurement with calibrated equipment.
What does “time averaging” mean when evaluating RF radiation exposure?
Answer D. Time averaging means the total RF exposure is averaged over a set period, rather than measured only at peaks.
What must you do if an evaluation of your station shows that the RF energy radiated by your station exceeds permissible limits for possible human absorption?
Answer A. If your station exceeds the limits, you must take action to prevent people from being exposed to the excessive RF fields.
What must you do if your station fails to meet the FCC RF exposure exemption criteria?
Answer A. If your station does not qualify for an exemption, you must perform an RF exposure evaluation following FCC OET Bulletin 65.
What is the effect of modulation duty cycle on RF exposure?
Answer A. A lower duty cycle means less average exposure, so greater power levels can be used within the limits.
Which of the following steps must an amateur operator take to ensure compliance with RF safety regulations?
Answer C. Perform a routine RF exposure evaluation, and prevent access to any high-exposure areas you identify.
What type of instrument can be used to accurately measure an RF field strength?
Answer B. Accurate field strength measurement needs a calibrated field strength meter with a calibrated antenna.
What should be done if evaluation shows that a neighbor might experience more than the allowable limit of RF exposure from the main lobe of a directional antenna?
Answer C. Take precautions so the antenna cannot be pointed at the neighbor while they are present.
What precaution should be taken if you install an indoor transmitting antenna?
Answer C. With an indoor antenna, make sure MPE limits are not exceeded in occupied areas.
What stations are subject to the FCC rules on RF exposure?
Answer D. FCC RF exposure rules apply to all stations with a time-averaged transmission of more than one milliwatt.
Which wire or wires in a four-conductor 240 VAC circuit should be attached to fuses or circuit breakers?
Answer A. Fuses or breakers go on the hot wires only. Never fuse the neutral or ground.
According to the National Electrical Code, what is the minimum wire size that may be used safely for wiring with a 20-ampere circuit breaker?
Answer C. The National Electrical Code requires at least AWG 12 wire on a 20-amp circuit.
Which size of fuse or circuit breaker would be appropriate to use with a circuit that uses AWG number 14 wiring?
Answer D. AWG 14 wire should be protected by a 15-amp fuse or breaker.
Where should the station’s lightning protection ground system be located?
Answer B. The lightning protection ground system belongs outside the building.
Which of the following conditions will cause a ground fault circuit interrupter (GFCI) to disconnect AC power?
Answer B. A GFCI trips when current flows from a hot wire directly to ground, a sign that current is leaking through an unintended path.
Which of the following is covered by the National Electrical Code?
Answer C. The National Electrical Code covers the electrical safety of the station.
Which of these choices should be observed when climbing a tower using a safety harness?
Answer B. Check that your harness is rated for the climber's weight and is within its allowable service life.
What should be done before climbing a tower that supports electrically powered devices?
Answer B. Before climbing, make sure all circuits that power devices on the tower are locked out and tagged.
Which of the following is true of an emergency generator installation?
Answer A. Generators produce carbon monoxide, so operate them only in well-ventilated areas.
Which of the following is a danger from lead-tin solder?
Answer A. Lead from solder can get onto food if you do not wash your hands carefully after handling it.
Which of the following is required for lightning protection ground rods?
Answer D. Lightning protection ground rods must be bonded together with all other grounds.
What is the purpose of a power supply interlock?
Answer C. A power supply interlock removes dangerous voltages when the cabinet is opened.
Where should lightning arrestors be located?
Answer A. Lightning arrestors go where the feed lines enter the building.
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