This N5HZR Correct Radio Amateur Answers Manual presents the entire FCC amateur radio General question pool without the distractors and is valid until June 30, 2027. This will help you study for FCC Volunteer Examiner Amateur Radio General test. More information is available at https:// h a m b o o k s dot o r g / c r a a m. Question 1... On which HF and/or MF amateur bands are there portions where General class licensees cannot transmit?... Answer 1... 80 meters, 40 meters, 20 meters, and 15 meters... Question 2... On which of the following bands is phone operation prohibited?... Answer 2... 30 meters... Question 3... On which of the following bands is image transmission prohibited?... Answer 3... 30 meters... Question 4... Which of the following amateur bands is restricted to communication only on specific channels, rather than frequency ranges?... Answer 4... 60 meters... Question 5... On which of the following frequencies are General class licensees prohibited from operating as control operator?... Answer 5... 7.125 MHz to 7.175 MHz... Question 6... Which of the following applies when the FCC rules designate the amateur service as a secondary user on a band?... Answer 6... Amateur stations must not cause harmful interference to primary users and must accept interference from primary users... Question 7... On which amateur frequencies in the 10-meter band may stations with a General class control operator transmit CW emissions?... Answer 7... The entire band... Question 8... Which HF bands have segments exclusively allocated to Amateur Extra licensees?... Answer 8... 80 meters, 40 meters, 20 meters, and 15 meters... Question 9... Which of the following frequencies is within the General class portion of the 15-meter band?... Answer 9... 21300 kHz... Question 10... What portion of the 10-meter band is available for repeater use?... Answer 10... The portion above 29.5 MHz... Question 11... 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 11... The upper frequency portion... Question 12... What is the maximum height above ground for an antenna structure near a public use airport without requiring notification to the FAA and registration with the FCC?... Answer 12... 200 feet... Question 13... With which of the following conditions must beacon stations comply?... Answer 13... No more than one beacon station may transmit in the same band from the same station location... Question 14... Which of the following is a purpose of a beacon station as identified in the FCC rules?... Answer 14... Observation of propagation and reception... Question 15... Which of the following transmissions is permitted for all amateur stations?... Answer 15... Occasional retransmission of weather and propagation forecast information from US government stations... Question 16... Which of the following one-way transmissions are permitted?... Answer 16... Transmissions to assist with learning the International Morse code... Question 17... Under what conditions are state and local governments permitted to regulate amateur radio antenna structures?... Answer 17... Amateur Service communications must be reasonably accommodated, and regulations must constitute the minimum practical to accommodate a legitimate purpose of the state or local entity... Question 18... What are the restrictions on the use of abbreviations or procedural signals in the amateur service?... Answer 18... They may be used if they do not obscure the meaning of a message... Question 19... When is it permissible to communicate with amateur stations in countries outside the areas administered by the Federal Communications Commission?... Answer 19... When the contact is with amateurs in any country except those whose administrations have notified the ITU that they object to such communications... Question 20... On what HF frequencies are automatically controlled beacons permitted?... Answer 20... 28.20 MHz to 28.30 MHz... Question 21... What is the power limit for beacon stations?... Answer 21... 100 watts PEP output... Question 22... 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 22... The FCC... Question 23... What is the maximum transmitting power an amateur station may use on 10.140 MHz?... Answer 23... 200 watts PEP output... Question 24... What is the maximum transmitting power an amateur station may use on the 12-meter band?... Answer 24... 1500 watts PEP output... Question 25... What is the maximum bandwidth permitted by FCC rules for amateur radio stations transmitting on USB frequencies in the 60-meter band?... Answer 25... 2.8 kHz... Question 26... Which of the following is required by the FCC rules when operating in the 60-meter band?... Answer 26... If you are using an antenna other than a dipole, you must keep a record of the gain of your antenna... Question 27... What is the limit for transmitter power on the 28 MHz band for a General Class control operator?... Answer 27... 1500 watts PEP output... Question 28... What is the limit for transmitter power on the 1.8 MHz band?... Answer 28... 1500 watts PEP output... Question 29... What must be done before using a new digital protocol on the air?... Answer 29... Publicly document the technical characteristics of the protocol... Question 30... What is the maximum power limit on the 60-meter band?... Answer 30... ERP of 100 watts PEP with respect to a dipole... Question 31... What measurement is specified by FCC rules that regulate maximum power?... Answer 31... PEP output from the transmitter... Question 32... Who may receive partial credit for the elements represented by an expired amateur radio license?... Answer 32... Any person who can demonstrate that they once held an FCC-issued General, Advanced, or Amateur Extra class license that was not revoked by the FCC... Question 33... What license examinations may you administer as an accredited Volunteer Examiner holding a General class operator license?... Answer 33... Technician only... Question 34... 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 34... On any General or Technician class band segment... Question 35... Who must observe the administration of a Technician class license examination?... Answer 35... At least three Volunteer Examiners of General class or higher... Question 36... When operating a US station by remote control from outside the country, what license is required of the control operator?... Answer 36... A US operator/primary station license... Question 37... 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 37... Whenever they operate using General class frequency privileges... Question 38... Volunteer Examiners are accredited by what organization?... Answer 38... A Volunteer Examiner Coordinator... Question 39... Which of the following criteria must be met for a non-US citizen to be an accredited Volunteer Examiner?... Answer 39... The person must hold an FCC granted amateur radio license of General class or above... Question 40... How long is a Certificate of Successful Completion of Examination (CSCE) valid for exam element credit?... Answer 40... 365 days... Question 41... What is the minimum age that one must be to qualify as an accredited Volunteer Examiner?... Answer 41... 18 years... Question 42... 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 42... The applicant must show proof of the appropriate expired license grant and pass the current Element 2 exam... Question 43... When operating a station in South America by remote control over the internet from the US, what regulations apply?... Answer 43... Only those of the remote station’s country... Question 44... Which of the following would disqualify a third party from participating in sending a message via an amateur station?... Answer 44... The third party’s amateur license has been revoked and not reinstated... Question 45... When may a 10-meter repeater retransmit the 2-meter signal from a station that has a Technician class control operator?... Answer 45... Only if the 10-meter repeater control operator holds at least a General class license... Question 46... What is required to conduct communications with a digital station operating under automatic control outside the automatic control band segments?... Answer 46... The station initiating the contact must be under local or remote control... Question 47... 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 47... When operating within one mile of an FCC Monitoring Station... Answer 47... When using a band where the Amateur Service is secondary... Answer 47... When a station is transmitting spread spectrum emissions... Answer 47... All these choices are correct... Question 48... What are the restrictions on messages sent to a third party in a country with which there is a Third-Party Agreement?... Answer 48... They must relate to amateur radio, or remarks of a personal character, or messages relating to emergencies or disaster relief... Question 49... The frequency allocations of which ITU region apply to radio amateurs operating in North and South America?... Answer 49... Region 2... Question 50... In what part of the 2.4 GHz band may an amateur station communicate with non-licensed Wi-Fi stations?... Answer 50... No part... Question 51... What is the maximum PEP output allowed for spread spectrum transmissions?... Answer 51... 10 watts... Question 52... Under what circumstances are messages that are sent via digital modes exempt from Part 97 third-party rules that apply to other modes of communication?... Answer 52... Under no circumstances... Question 53... Why should an amateur operator normally avoid transmitting on 14.100, 18.110, 21.150, 24. 930 and 28.200 MHz?... Answer 53... A system of propagation beacon stations operates on those frequencies... Question 54... On what bands may automatically controlled stations transmitting RTTY or data emissions communicate with other automatically controlled digital stations?... Answer 54... Anywhere in the 6-meter or shorter wavelength bands, and in limited segments of some of the HF bands... Question 55... When may third-party messages be transmitted via remote control?... Answer 55... Under any circumstances in which third party messages are permitted by FCC rules... Question 56... Which mode is most commonly used for voice communications on frequencies of 14 MHz or higher?... Answer 56... Upper sideband... Question 57... Which mode is most commonly used for voice communications on the 160-, 75-, and 40-meter bands?... Answer 57... Lower sideband... Question 58... Which mode is most commonly used for SSB voice communications in the VHF and UHF bands?... Answer 58... Upper sideband... Question 59... Which mode is most commonly used for voice communications on the 17- and 12-meter bands?... Answer 59... Upper sideband... Question 60... Which mode of voice communication is most commonly used on the HF amateur bands?... Answer 60... Single sideband... Question 61... Which of the following is an advantage of using single sideband, as compared to other analog voice modes on the HF amateur bands?... Answer 61... Less bandwidth used and greater power efficiency... Question 62... Which of the following statements is true of single sideband (SSB)?... Answer 62... Only one sideband is transmitted; the other sideband and carrier are suppressed... Question 63... What is the recommended way to break into a phone contact?... Answer 63... Say your call sign once... Question 64... Why do most amateur stations use lower sideband on the 160-, 75-, and 40-meter bands?... Answer 64... It is commonly accepted amateur practice... Question 65... Which of the following statements is true of VOX operation versus PTT operation?... Answer 65... It allows “hands free” operation... Question 66... Generally, who should respond to a station in the contiguous 48 states calling “CQ DX”?... Answer 66... Any stations outside the lower 48 states... Question 67... What control is typically adjusted for proper ALC setting on a single sideband transceiver?... Answer 67... Transmit audio or microphone gain... Question 68... Which of the following is true concerning access to frequencies?... Answer 68... Except during emergencies, no amateur station has priority access to any frequency... Question 69... 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 69... Acknowledge the station in distress and determine what assistance may be needed... Question 70... What is good amateur practice if propagation changes during a contact creating interference from other stations using the frequency?... Answer 70... Attempt to resolve the interference problem with the other stations in a mutually acceptable manner... Question 71... When selecting a CW transmitting frequency, what minimum separation from other stations should be used to minimize interference to stations on adjacent frequencies?... Answer 71... 150 Hz to 500 Hz... Question 72... When selecting an SSB transmitting frequency, what minimum separation should be used to minimize interference to stations on adjacent frequencies?... Answer 72... 2 kHz to 3 kHz... Question 73... How can you avoid harmful interference on an apparently clear frequency before calling CQ on CW or phone?... Answer 73... Send “QRL?” on CW, followed by your call sign; or, if using phone, ask if the frequency is in use, followed by your call sign... Question 74... Which of the following complies with commonly accepted amateur practice when choosing a frequency on which to initiate a call?... Answer 74... Follow the voluntary band plan... Question 75... 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 75... Only contacts with stations not within the 48 contiguous states... Question 76... Who may be the control operator of an amateur station transmitting in RACES to assist relief operations during a disaster?... Answer 76... Only a person holding an FCC-issued amateur operator license... Question 77... Which of the following is good amateur practice for net management?... Answer 77... Have a backup frequency in case of interference or poor conditions... Question 78... How often may RACES training drills and tests be routinely conducted without special authorization?... Answer 78... No more than 1 hour per week... Question 79... Which of the following describes full break-in CW operation (QSK)?... Answer 79... Transmitting stations can receive between code characters and elements... Question 80... What should you do if a CW station sends “QRS?”... Answer 80... Send slower... Question 81... What does it mean when a CW operator sends “KN” at the end of a transmission?... Answer 81... Listening only for a specific station or stations... Question 82... What does the Q signal “QRL?” mean?... Answer 82... “Are you busy?” or “Is this frequency in use?”... Question 83... What is the best speed to use when answering a CQ in Morse code?... Answer 83... The fastest speed at which you are comfortable copying, but no faster than the CQ... Question 84... ... Answer 84... What does the term “zero beat” mean in CW operation?... Answer 84... Matching the transmit frequency to the frequency of a received signal... Question 85... When sending CW, what does a “C” mean when added to the RST report?... Answer 85... Chirpy or unstable signal... Question 86... What prosign is sent to indicate the end of a formal message when using CW?... Answer 86... AR... Question 87... What does the Q signal “QSL” mean?... Answer 87... I have received and understood... Question 88... What does the Q signal “QRN” mean?... Answer 88... I am troubled by static... Question 89... What does the Q signal “QRV” mean?... Answer 89... I am ready to receive... Question 90... What is the Volunteer Monitor Program?... Answer 90... Amateur volunteers who are formally enlisted to monitor the airwaves for rules violations... Question 91... Which of the following are objectives of the Volunteer Monitor Program?... Answer 91... To encourage amateur radio operators to self-regulate and comply with the rules... Question 92... What procedure may be used by Volunteer Monitors to localize a station whose continuous carrier is holding a repeater on in their area?... Answer 92... Compare beam headings on the repeater input from their home locations with that of other Volunteer Monitors... Question 93... Which of the following describes an azimuthal projection map?... Answer 93... A map that shows true bearings and distances from a specific location... Question 94... Which of the following indicates that you are looking for an HF contact with any station?... Answer 94... Repeat “CQ” a few times, followed by “this is,” then your call sign a few times, then pause to listen, repeat as necessary... Question 95... How is a directional antenna pointed when making a “long-path” contact with another station?... Answer 95... 180 degrees from the station’s short-path heading... Question 96... Which of the following are examples of the NATO Phonetic Alphabet?... Answer 96... Alpha, Bravo, Charlie, Delta... Question 97... Why do many amateurs keep a station log?... Answer 97... To help with a reply if the FCC requests information about your station... Question 98... Which of the following is required when participating in a contest on HF frequencies?... Answer 98... Identify your station according to normal FCC regulations... Question 99... What is QRP operation?... Answer 99... Low-power transmit operation... Question 100... Why are signal reports typically exchanged at the beginning of an HF contact?... Answer 100... To allow each station to operate according to conditions... Question 101... Which mode is normally used when sending RTTY signals via AFSK with an SSB transmitter?... Answer 101... LSB... Question 102... What is VARA?... Answer 102... A digital protocol used with Winlink... Question 103... What symptoms may result from other signals interfering with a PACTOR or VARA transmission?... Answer 103... Frequent retries or timeouts... Answer 103... Long pauses in message transmission... Answer 103... Failure to establish a connection between stations... Answer 103... All these choices are correct... Question 104... Which of the following is good practice when choosing a transmitting frequency to answer a station calling CQ using FT8?... Answer 104... Find a clear frequency during the alternate time slot to the calling station... Question 105... What is the standard sideband for JT65, JT9, FT4, or FT8 digital signal when using AFSK?... Answer 105... USB... Question 106... What is the most common frequency shift for RTTY emissions in the amateur HF bands?... Answer 106... 170 Hz... Question 107... Which of the following is required when using FT8?... Answer 107... Computer time accurate to within approximately 1 second... Question 108... In what segment of the 20-meter band are most digital mode operations commonly found?... Answer 108... Between 14.070 MHz and 14.100 MHz... Question 109... How do you join a contact between two stations using the PACTOR protocol?... Answer 109... Joining an existing contact is not possible, PACTOR connections are limited to two stations... Question 110... Which of the following is a way to establish contact with a digital messaging system gateway station?... Answer 110... Transmit a connect message on the station’s published frequency... Question 111... What is the primary purpose of an Amateur Radio Emergency Data Network (AREDN) mesh network?... Answer 111... To provide high-speed data services during an emergency or community event... Question 112... Which of the following describes Winlink?... Answer 112... An amateur radio wireless network to send and receive email on the internet... Answer 112... A form of Packet Radio... Answer 112... A wireless network capable of both VHF and HF band operation... Answer 112... All of the above... Question 113... What is another name for a Winlink Remote Message Server?... Answer 113... Gateway... Question 114... What could be wrong if you cannot decode an RTTY or other FSK signal even though it is apparently tuned in properly?... Answer 114... The mark and space frequencies may be reversed... Answer 114... You may have selected the wrong baud rate... Answer 114... You may be listening on the wrong sideband... Answer 114... All these choices are correct... Question 115... Which of the following is a common location for FT8?... Answer 115... Approximately 14.074 MHz to 14.077 MHz... Question 116... How does a higher sunspot number affect HF propagation?... Answer 116... Higher sunspot numbers generally indicate a greater probability of good propagation at higher frequencies... Question 117... What effect does a sudden ionospheric disturbance have on the daytime ionospheric propagation?... Answer 117... It disrupts signals on lower frequencies more than those on higher frequencies... Question 118... Approximately how long does it take the increased ultraviolet and X-ray radiation from a solar flare to affect radio propagation on Earth?... Answer 118... 8 minutes... Question 119... Which of the following are the least reliable bands for long-distance communications during periods of low solar activity?... Answer 119... 15 meters, 12 meters, and 10 meters... Question 120... What is the solar flux index?... Answer 120... A measure of solar radiation with a wavelength of 10.7 centimeters... Question 121... What is a geomagnetic storm?... Answer 121... A temporary disturbance in Earth’s geomagnetic field... Question 122... At what point in the solar cycle does the 20-meter band usually support worldwide propagation during daylight hours?... Answer 122... At any point... Question 123... How can a geomagnetic storm affect HF propagation?... Answer 123... Degrade high-latitude HF propagation... Question 124... How can high geomagnetic activity benefit radio communications?... Answer 124... Creates auroras that can reflect VHF signals... Question 125... What causes HF propagation conditions to vary periodically in a 26- to 28-day cycle?... Answer 125... Rotation of the Sun’s surface layers around its axis... Question 126... How long does it take a coronal mass ejection to affect radio propagation on Earth?... Answer 126... 15 hours to several days... Question 127... What does the K-index measure?... Answer 127... The short-term stability of Earth’s geomagnetic field... Question 128... What does the A-index measure?... Answer 128... The long-term stability of Earth’s geomagnetic field... Question 129... How is long distance radio communication usually affected by the charged particles that reach Earth from solar coronal holes?... Answer 129... HF communication is disturbed... Question 130... What is a characteristic of skywave signals arriving at your location by both short-path and long-path propagation?... Answer 130... A slightly delayed echo might be heard... Question 131... What factors affect the MUF?... Answer 131... Path distance and location... Answer 131... Time of day and season... Answer 131... Solar radiation and ionospheric disturbances... Answer 131... All these choices are correct... Question 132... Which frequency will have the least attenuation for long-distance skip propagation?... Answer 132... Just below the MUF... Question 133... Which of the following is a way to determine current propagation on a desired band from your station?... Answer 133... Use a network of automated receiving stations on the internet to see where your transmissions are being received... Question 134... How does the ionosphere affect radio waves with frequencies below the MUF and above the LUF?... Answer 134... They are refracted back to Earth... Question 135... What usually happens to radio waves with frequencies below the LUF?... Answer 135... They are attenuated before reaching the destination... Question 136... What does LUF stand for?... Answer 136... The Lowest Usable Frequency for communications between two specific points... Question 137... What does MUF stand for?... Answer 137... The Maximum Usable Frequency for communications between two points... Question 138... What is the approximate maximum distance along the Earth’s surface normally covered in one hop using the F2 region?... Answer 138... 2,500 miles... Question 139... What is the approximate maximum distance along the Earth’s surface normally covered in one hop using the E region?... Answer 139... 1,200 miles... Question 140... What happens to HF propagation when the LUF exceeds the MUF?... Answer 140... Propagation via ordinary skywave communications is not possible over that path... Question 141... Which of the following is typical of the lower HF frequencies during the summer?... Answer 141... High levels of atmospheric noise or static... Question 142... Which ionospheric region is closest to the surface of Earth?... Answer 142... The D region... Question 143... What is meant by the term “critical frequency” at a given incidence angle?... Answer 143... The highest frequency which is refracted back to Earth... Question 144... Why is skip propagation via the F2 region longer than that via the other ionospheric regions?... Answer 144... Because it is the highest... Question 145... What does the term “critical angle” mean, as applied to radio wave propagation?... Answer 145... The highest takeoff angle that will return a radio wave to Earth under specific ionospheric conditions... Question 146... Why is long-distance communication on the 40-, 60-, 80-, and 160-meter bands more difficult during the day?... Answer 146... The D region absorbs signals at these frequencies during daylight hours... Question 147... What is a characteristic of HF scatter?... Answer 147... Signals have a fluttering sound... Question 148... What makes HF scatter signals often sound distorted?... Answer 148... Energy is scattered into the skip zone through several different paths... Question 149... Why are HF scatter signals in the skip zone usually weak?... Answer 149... Only a small part of the signal energy is scattered into the skip zone... Question 150... What type of propagation allows signals to be heard in the transmitting station’s skip zone?... Answer 150... Scatter... Question 151... What is near vertical incidence skywave (NVIS) propagation?... Answer 151... Short distance MF or HF propagation at high elevation angles... Question 152... Which ionospheric region is the most absorbent of signals below 10 MHz during daylight hours?... Answer 152... The D region... Question 153... What is the purpose of the notch filter found on many HF transceivers?... Answer 153... To reduce interference from carriers in the receiver passband... Question 154... What is the benefit of using the opposite or “reverse” sideband when receiving CW?... Answer 154... It may be possible to reduce or eliminate interference from other signals... Question 155... How does a noise blanker work?... Answer 155... By reducing receiver gain during a noise pulse... Question 156... What is the effect on plate current of the correct setting of a vacuum-tube RF power amplifier’s TUNE control?... Answer 156... A pronounced dip... Question 157... Why is automatic level control (ALC) used with an RF power amplifier?... Answer 157... To prevent excessive drive... Question 158... What is the purpose of an antenna tuner?... Answer 158... Increase power transfer from the transmitter to the feed line... Question 159... What happens as a receiver’s noise reduction control level is increased?... Answer 159... Received signals may become distorted... Question 160... What is the correct adjustment for the LOAD or COUPLING control of a vacuum tube RF power amplifier?... Answer 160... Desired power output without exceeding maximum allowable plate current... Question 161... What is the purpose of delaying RF output after activating a transmitter’s keying line to an external amplifier?... Answer 161... To allow time for the amplifier to switch the antenna between the transceiver and the amplifier output... Question 162... What is the function of an electronic keyer?... Answer 162... Automatic generation of dots and dashes for CW operation... Question 163... Why should the ALC system be inactive when transmitting AFSK data signals?... Answer 163... The ALC action distorts the signal... Question 164... Which of the following is a common use of the dual-VFO feature on a transceiver?... Answer 164... To transmit on one frequency and listen on another... Question 165... What is the purpose of using a receive attenuator?... Answer 165... To prevent receiver overload from strong incoming signals... Question 166... What item of test equipment contains horizontal and vertical channel amplifiers?... Answer 166... An oscilloscope... Question 167... Which of the following is an advantage of an oscilloscope versus a digital voltmeter?... Answer 167... Complex waveforms can be measured... Question 168... Which of the following is the best instrument to use for checking the keying waveform of a CW transmitter?... Answer 168... An oscilloscope... Question 169... What signal source is connected to the vertical input of an oscilloscope when checking the RF envelope pattern of a transmitted signal?... Answer 169... The attenuated RF output of the transmitter... Question 170... Why do voltmeters have high input impedance?... Answer 170... It decreases the loading on circuits being measured... Question 171... What is an advantage of a digital multimeter as compared to an analog multimeter?... Answer 171... Higher precision... Question 172... What signals are used to conduct a two-tone test?... Answer 172... Two non-harmonically related audio signals... Question 173... What transmitter performance parameter does a two-tone test analyze?... Answer 173... Linearity... Question 174... When is an analog multimeter preferred to a digital multimeter?... Answer 174... When adjusting circuits for maximum or minimum values... Question 175... Which of the following can be determined with a directional wattmeter?... Answer 175... Standing wave ratio... Question 176... Which of the following must be connected to an antenna analyzer when it is being used for SWR measurements?... Answer 176... Antenna and feed line... Question 177... What effect can strong signals from nearby transmitters have on an antenna analyzer?... Answer 177... Received power that interferes with SWR readings... Question 178... Which of the following can be measured with an antenna analyzer?... Answer 178... Impedance of coaxial cable... Question 179... Which of the following might be useful in reducing RF interference to audio frequency circuits?... Answer 179... Bypass capacitor... Question 180... Which of the following could be a cause of interference covering a wide range of frequencies?... Answer 180... Arcing at a poor electrical connection... Question 181... What sound is heard from an audio device experiencing RF interference from a single sideband phone transmitter?... Answer 181... Distorted speech... Question 182... What sound is heard from an audio device experiencing RF interference from a CW transmitter?... Answer 182... On-and-off humming or clicking... Question 183... What is a possible cause of high voltages that produce RF burns?... Answer 183... The ground wire has high impedance on that frequency... Question 184... What is a possible effect of a resonant ground connection?... Answer 184... High RF voltages on the enclosures of station equipment... Question 185... Why should soldered joints not be used in lightning protection ground connections?... Answer 185... A soldered joint will likely be destroyed by the heat of a lightning strike... Question 186... Which of the following would reduce RF interference caused by common-mode current on an audio cable?... Answer 186... Place a ferrite choke on the cable... Question 187... How can the effects of ground loops be minimized?... Answer 187... Bond equipment enclosures together... Question 188... What could be a symptom caused by a ground loop in your station’s audio connections?... Answer 188... You receive reports of “hum” on your station’s transmitted signal... Question 189... What technique helps to minimize RF “hot spots” in an amateur station?... Answer 189... Bonding all equipment enclosures together... Question 190... Why must all metal enclosures of station equipment be grounded?... Answer 190... It ensures that hazardous voltages cannot appear on the chassis... Question 191... What is the purpose of a speech processor in a transceiver?... Answer 191... Increase the apparent loudness of transmitted voice signals... Question 192... How does a speech processor affect a single sideband phone signal?... Answer 192... It increases average power... Question 193... What is the effect of an incorrectly adjusted speech processor?... Answer 193... Distorted speech... Answer 193... Excess intermodulation products... Answer 193... Excessive background noise... Answer 193... All these choices are correct... Question 194... What does an S meter measure?... Answer 194... Received signal strength... Question 195... 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 195... It is 100 times more powerful... Question 196... How much change in signal strength is typically represented by one S unit?... Answer 196... 6 dB... Question 197... 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 197... Approximately 4 times... Question 198... What frequency range is occupied by a 3 kHz LSB signal when the displayed carrier frequency is set to 7.178 MHz?... Answer 198... 7.175 MHz to 7.178 MHz... Question 199... What frequency range is occupied by a 3 kHz USB signal with the displayed carrier frequency set to 14.347 MHz?... Answer 199... 14.347 MHz to 14.350 MHz... Question 200... 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 200... At least 3 kHz above the edge of the segment... Question 201... 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 201... At least 3 kHz below the edge of the band... Question 202... What is the purpose of a capacitance hat on a mobile antenna?... Answer 202... To electrically lengthen a physically short antenna... Question 203... What is the purpose of a corona ball on an HF mobile antenna?... Answer 203... To reduce RF voltage discharge from the tip of the antenna while transmitting... Question 204... Which of the following direct, fused power connections would be the best for a 100-watt HF mobile installation?... Answer 204... To the battery using heavy-gauge wire... Question 205... Why should DC power for a 100-watt HF transceiver not be supplied by a vehicle’s auxiliary power socket?... Answer 205... The socket’s wiring may be inadequate for the current drawn by the transceiver... Question 206... Which of the following most limits an HF mobile installation?... Answer 206... Efficiency of the electrically short antenna... Question 207... What is one disadvantage of using a shortened mobile antenna as opposed to a full-size antenna?... Answer 207... Operating bandwidth may be very limited... Question 208... Which of the following may cause receive interference to an HF transceiver installed in a vehicle?... Answer 208... The battery charging system... Answer 208... The fuel delivery system... Answer 208... The control computers... Answer 208... All these choices are correct... Question 209... In what configuration are the individual cells in a solar panel connected together?... Answer 209... Series-parallel... Question 210... What is the approximate open-circuit voltage from a fully illuminated silicon photovoltaic cell?... Answer 210... 0.5 VDC... Question 211... Why should a series diode be connected between a solar panel and a storage battery that is being charged by the panel?... Answer 211... To prevent discharge of the battery through the panel during times of low or no illumination... Question 212... What precaution should be taken when connecting a solar panel to a lithium iron phosphate battery?... Answer 212... The solar panel must have a charge controller... Question 213... What happens when inductive and capacitive reactance are equal in a series LC circuit?... Answer 213... Resonance causes impedance to be very low... Question 214... What is reactance?... Answer 214... Opposition to the flow of alternating current caused by capacitance or inductance... Question 215... Which of the following is opposition to the flow of alternating current in an inductor?... Answer 215... Reactance... Question 216... Which of the following is opposition to the flow of alternating current in a capacitor?... Answer 216... Reactance... Question 217... How does an inductor react to AC?... Answer 217... As the frequency of the applied AC increases, the reactance increases... Question 218... How does a capacitor react to AC?... Answer 218... As the frequency of the applied AC increases, the reactance decreases... Question 219... What is the term for the inverse of impedance?... Answer 219... Admittance... Question 220... What is impedance?... Answer 220... The ratio of voltage to current... Question 221... What unit is used to measure reactance?... Answer 221... Ohm... Question 222... Which of the following devices can be used for impedance matching at radio frequencies?... Answer 222... A transformer... Answer 222... A Pi-network... Answer 222... A length of transmission line... Answer 222... All these choices are correct... Question 223... What letter is used to represent reactance?... Question 224... ... Answer 224... What occurs in an LC circuit at resonance?... Answer 224... Inductive reactance and capacitive reactance cancel... Question 225... What dB change represents a factor of two increase or decrease in power?... Answer 225... Approximately 3 dB... Question 226... How does the total current relate to the individual currents in a circuit of parallel resistors?... Answer 226... It equals the sum of the currents through each branch... Question 227... How many watts of electrical power are consumed if 400 VDC is supplied to an 800-ohm load?... Answer 227... 200 watts... Question 228... How many watts of electrical power are consumed by a 12 VDC light bulb that draws 0.2 amperes?... Answer 228... 2.4 watts... Question 229... How many watts are consumed when a current of 7.0 milliamperes flows through a 1,250-ohm resistance?... Answer 229... Approximately 61 milliwatts... Question 230... What is the PEP produced by 200 volts peak-to-peak across a 50-ohm dummy load?... Answer 230... 100 watts... Question 231... What value of an AC signal produces the same power dissipation in a resistor as a DC voltage of the same value?... Answer 231... The RMS value... Question 232... What is the peak-to-peak voltage of a sine wave with an RMS voltage of 120 volts?... Answer 232... 339.4 volts... Question 233... What is the RMS voltage of a sine wave with a value of 17 volts peak?... Answer 233... 12 volts... Question 234... What percentage of power loss is equivalent to a loss of 1 dB?... Answer 234... 20.6 percent... Question 235... What is the ratio of PEP to average power for an unmodulated carrier?... Answer 235... 1.00... Question 236... What is the RMS voltage across a 50-ohm dummy load dissipating 1200 watts?... Answer 236... 245 volts... Question 237... What is the output PEP of an unmodulated carrier if the average power is 1060 watts?... Answer 237... 1060 watts... Question 238... What is the output PEP of 500 volts peak-to-peak across a 50-ohm load?... Answer 238... 625 watts... Question 239... 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 239... Mutual inductance... Question 240... What is the output voltage if an output signal is applied to the secondary winding of a 4:1 voltage step-down transformer instead of the primary winding?... Answer 240... The input voltage is multiplied by 4... Question 241... What is the total resistance of a 10-, a 20-, and a 50-ohm resistor connected in parallel?... Answer 241... 5.9 ohms... Question 242... What is the approximate total resistance of a 100- and a 200-ohm resistor in parallel?... Answer 242... 67 ohms... Question 243... Why is the primary winding wire of a voltage step-up transformer usually a larger size than that of the secondary winding?... Answer 243... To accommodate the higher current of the primary... Question 244... 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 244... 360 volts... Question 245... What transformer turns ratio matches an antenna’s 600-ohm feed point impedance to a 50-ohm coaxial cable?... Answer 245... 3.5 to 1... Question 246... What is the equivalent capacitance of two 5.0-nanofarad capacitors and one 750-picofarad capacitor connected in parallel?... Answer 246... 10.750 nanofarads... Question 247... What is the capacitance of three 100-microfarad capacitors connected in series?... Answer 247... 33.3 microfarads... Question 248... What is the inductance of three 10-millihenry inductors connected in parallel?... Answer 248... 3.3 millihenries... Question 249... What is the inductance of a circuit with a 20-millihenry inductor connected in series with a 50-millihenry inductor?... Answer 249... 70 millihenries... Question 250... What is the capacitance of a 20-microfarad capacitor connected in series with a 50-microfarad capacitor?... Answer 250... 14.3 microfarads... Question 251... Which of the following components should be added to a capacitor to increase the capacitance?... Answer 251... A capacitor in parallel... Question 252... Which of the following components should be added to an inductor to increase the inductance?... Answer 252... An inductor in series... Question 253... What is the minimum allowable discharge voltage for maximum life of a standard 12-volt lead-acid battery?... Answer 253... 10.5 volts... Question 254... What is an advantage of batteries with low internal resistance?... Answer 254... High discharge current... Question 255... What is the approximate forward threshold voltage of a germanium diode?... Answer 255... 0.3 volts... Question 256... Which of the following is characteristic of an electrolytic capacitor?... Answer 256... High capacitance for a given volume... Question 257... What is the approximate forward threshold voltage of a silicon junction diode?... Answer 257... 0.7 volts... Question 258... Why should wire-wound resistors not be used in RF circuits?... Answer 258... The resistor’s inductance could make circuit performance unpredictable... Question 259... What are the operating points for a bipolar transistor used as a switch?... Answer 259... Saturation and cutoff... Question 260... Which of the following is characteristic of low voltage ceramic capacitors?... Answer 260... Comparatively low cost... Question 261... Which of the following describes MOSFET construction?... Answer 261... The gate is separated from the channel by a thin insulating layer... Question 262... Which element of a vacuum tube regulates the flow of electrons between cathode and plate?... Answer 262... Control grid... Question 263... What happens when an inductor is operated above its self-resonant frequency?... Answer 263... It becomes capacitive... Question 264... What is the primary purpose of a screen grid in a vacuum tube?... Answer 264... To reduce grid-to-plate capacitance... Question 265... What determines the performance of a ferrite core at different frequencies?... Answer 265... The composition, or “mix,” of materials used... Question 266... What is meant by the term MMIC?... Answer 266... Monolithic Microwave Integrated Circuit... Question 267... Which of the following is an advantage of CMOS integrated circuits compared to TTL integrated circuits?... Answer 267... Low power consumption... Question 268... What is a typical upper frequency limit for low SWR operation of 50-ohm BNC connectors?... Answer 268... 4 GHz... Question 269... What is an advantage of using a ferrite core toroidal inductor?... Answer 269... Large values of inductance may be obtained... Answer 269... The magnetic properties of the core may be optimized for a specific range of frequencies... Answer 269... Most of the magnetic field is contained in the core... Answer 269... All these choices are correct... Question 270... What kind of device is an integrated circuit operational amplifier?... Answer 270... Analog... Question 271... Which of the following describes a type N connector?... Answer 271... A moisture-resistant RF connector useful to 10 GHz... Question 272... How is an LED biased when emitting light?... Answer 272... Forward biased... Question 273... How does a ferrite bead or core reduce common-mode RF current on the shield of a coaxial cable?... Answer 273... By creating an impedance in the current’s path... Question 274... What is an SMA connector?... Answer 274... A small threaded connector suitable for signals up to several GHz... Question 275... Which of these connector types is commonly used for low frequency or dc signal connections to a transceiver?... Answer 275... RCA Phono... Question 276... What is the function of a power supply bleeder resistor?... Answer 276... It discharges the filter capacitors when power is removed... Question 277... Which of the following components are used in a power supply filter network?... Answer 277... Capacitors and inductors... Question 278... Which type of rectifier circuit uses two diodes and a center-tapped transformer?... Answer 278... Full-wave... Question 279... What is characteristic of a half-wave rectifier in a power supply?... Answer 279... Only one diode is required... Question 280... What portion of the AC cycle is converted to DC by a half-wave rectifier?... Answer 280... 180 degrees... Question 281... What portion of the AC cycle is converted to DC by a full-wave rectifier?... Answer 281... 360 degrees... Question 282... What is the output waveform of an unfiltered full-wave rectifier connected to a resistive load?... Answer 282... A series of DC pulses at twice the frequency of the AC input... Question 283... Which of the following is characteristic of a switchmode power supply as compared to a linear power supply?... Answer 283... High-frequency operation allows the use of smaller components... Question 284... What is the purpose of neutralizing an amplifier?... Answer 284... To eliminate self-oscillations... Question 285... Which of these classes of amplifiers has the highest efficiency?... Answer 285... Class C... Question 286... Which of the following describes the function of a two-input AND gate?... Answer 286... Output is high only when both inputs are high... Question 287... In a Class A amplifier, what percentage of the time does the amplifying device conduct?... Answer 287... 100%... Question 288... How many states does a 3-bit binary counter have?... Question 289... ... Answer 289... What is a shift register?... Answer 289... A clocked array of circuits that passes data in steps along the array... Question 290... Which of the following are basic components of a sine wave oscillator?... Answer 290... A filter and an amplifier operating in a feedback loop... Question 291... How is the efficiency of an RF power amplifier determined?... Answer 291... Divide the RF output power by the DC input power... Question 292... What determines the frequency of an LC oscillator?... Answer 292... The inductance and capacitance in the tank circuit... Question 293... Which of the following describes a linear amplifier?... Answer 293... An amplifier in which the output preserves the input waveform... Question 294... For which of the following modes is a Class C power stage appropriate for amplifying a modulated signal?... Answer 294... FM... Question 295... What circuit is used to select one of the sidebands from a balanced modulator?... Answer 295... Filter... Question 296... What output is produced by a balanced modulator?... Answer 296... Double-sideband modulated RF... Question 297... What is one reason to use an impedance matching transformer at a transmitter output?... Answer 297... To present the desired impedance to the transmitter and feed line... Question 298... How is a product detector used?... Answer 298... Used in a single sideband receiver to extract the modulated signal... Question 299... Which of the following is characteristic of a direct digital synthesizer (DDS)?... Answer 299... Variable output frequency with the stability of a crystal oscillator... Question 300... Which of the following is an advantage of a digital signal processing (DSP) filter compared to an analog filter?... Answer 300... A wide range of filter bandwidths and shapes can be created... Question 301... What term specifies a filter’s attenuation inside its passband?... Answer 301... Insertion loss... Question 302... Which parameter affects receiver sensitivity?... Answer 302... Input amplifier gain... Answer 302... Demodulator stage bandwidth... Answer 302... Input amplifier noise figure... Answer 302... All these choices are correct... Question 303... What is the phase difference between the I and Q RF signals that software-defined radio (SDR) equipment uses for modulation and demodulation?... Answer 303... 90 degrees... Question 304... What is an advantage of using I-Q modulation with software-defined radios (SDRs)?... Answer 304... All types of modulation can be created with appropriate processing... Question 305... Which of these functions is performed by software in a software-defined radio (SDR)?... Answer 305... Filtering... Answer 305... Detection... Answer 305... Modulation... Answer 305... All these choices are correct... Question 306... What is the frequency above which a low-pass filter’s output power is less than half the input power?... Answer 306... Cutoff frequency... Question 307... What term specifies a filter’s maximum ability to reject signals outside its passband?... Answer 307... Ultimate rejection... Question 308... The bandwidth of a band-pass filter is measured between what two frequencies?... Answer 308... Upper and lower half-power... Question 309... How is direct binary FSK modulation generated?... Answer 309... By changing an oscillator’s frequency directly with a digital control signal... Question 310... What is the name of the process that changes the phase angle of an RF signal to convey information?... Answer 310... Phase modulation... Question 311... What is the name of the process that changes the instantaneous frequency of an RF wave to convey information?... Answer 311... Frequency modulation... Question 312... What emission is produced by a reactance modulator connected to a transmitter RF amplifier stage?... Answer 312... Phase modulation... Question 313... What type of modulation varies the instantaneous power level of the RF signal?... Answer 313... Amplitude modulation... Question 314... Which of the following is characteristic of QPSK31?... Answer 314... It is sideband sensitive... Answer 314... Its encoding provides error correction... Answer 314... Its bandwidth is approximately the same as BPSK31... Answer 314... All these choices are correct... Question 315... Which of the following phone emissions uses the narrowest bandwidth?... Answer 315... Single sideband... Question 316... Which of the following is an effect of overmodulation?... Answer 316... Excessive bandwidth... Question 317... What type of modulation is used by FT8?... Answer 317... 8-tone frequency shift keying... Question 318... What is meant by the term “flat-topping,” when referring to an amplitude-modulated phone signal?... Answer 318... Signal distortion caused by excessive drive or speech levels... Question 319... What is the modulation envelope of an AM signal?... Answer 319... The waveform created by connecting the peak values of the modulated signal... Question 320... What is QPSK modulation?... Answer 320... Modulation in which digital data is transmitted using 0-, 90-, 180- and 270-degrees phase shift to represent pairs of bits... Question 321... What is a link budget?... Answer 321... The sum of transmit power and antenna gains minus system losses as seen at the receiver... Question 322... What is link margin?... Answer 322... The difference between received power level and minimum required signal level at the input to the receiver... Question 323... Which mixer input is varied or tuned to convert signals of different frequencies to an intermediate frequency (IF)?... Answer 323... Local oscillator... Question 324... What is the term for interference from a signal at twice the IF frequency from the desired signal?... Answer 324... Image response... Question 325... What is another term for the mixing of two RF signals?... Answer 325... Heterodyning... Question 326... 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 326... Multiplier... Question 327... Which intermodulation products are closest to the original signal frequencies?... Answer 327... Odd-order... Question 328... What is the total bandwidth of an FM phone transmission having 5 kHz deviation and 3 kHz modulating frequency?... Answer 328... 16 kHz... Question 329... 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 329... 416.7 Hz... Question 330... Why is it important to know the duty cycle of the mode you are using when transmitting?... Answer 330... Some modes have high duty cycles that could exceed the transmitter’s average power rating... Question 331... Why is it good to match receiver bandwidth to the bandwidth of the operating mode?... Answer 331... It results in the best signal-to-noise ratio... Question 332... What is the relationship between transmitted symbol rate and bandwidth?... Answer 332... Higher symbol rates require wider bandwidth... Question 333... What combination of a mixer’s Local Oscillator (LO) and RF input frequencies is found in the output?... Answer 333... The sum and difference... Question 334... What process combines two signals in a non-linear circuit to produce unwanted spurious outputs?... Answer 334... Intermodulation... Question 335... Which of the following is an odd-order intermodulation product of frequencies F1 and F2?... Answer 335... 2F1-F2... Question 336... On what band do amateurs share channels with the unlicensed Wi-Fi service?... Answer 336... 2.4 GHz... Question 337... Which digital mode is used as a low-power beacon for assessing HF propagation?... Answer 337... WSPR... Question 338... What part of a packet radio frame contains the routing and handling information?... Answer 338... Header... Question 339... Which of the following describes Baudot code?... Answer 339... A 5-bit code with additional start and stop bits... Question 340... In an ARQ mode, what is meant by a NAK response to a transmitted packet?... Answer 340... Request retransmission of the packet... Question 341... What action results from a failure to exchange information due to excessive transmission attempts when using an ARQ mode?... Answer 341... The connection is dropped... Question 342... Which of the following narrow-band digital modes can receive signals with very low signal-to-noise ratios?... Answer 342... FT8... Question 343... Which of the following statements is true about PSK31?... Answer 343... Upper case letters use longer Varicode bit sequences and thus slow down transmission... Question 344... Which is true of mesh network microwave nodes?... Answer 344... If one node fails, a packet may still reach its target station via an alternate node... Question 345... How does forward error correction (FEC) allow the receiver to correct data errors?... Answer 345... By transmitting redundant information with the data... Question 346... How are the two separate frequencies of a Frequency Shift Keyed (FSK) signal identified?... Answer 346... Mark and space... Question 347... Which type of code is used for sending characters in a PSK31 signal?... Answer 347... Varicode... Question 348... What is indicated on a waterfall display by one or more vertical lines on either side of a data mode or RTTY signal?... Answer 348... Overmodulation... Question 349... Which of the following describes a waterfall display?... Answer 349... Frequency is horizontal, signal strength is intensity, time is vertical... Question 350... What does an FT8 signal report of +3 mean?... Answer 350... The signal-to-noise ratio is equivalent to +3dB in a 2.5 kHz bandwidth... Question 351... Which of the following provide digital voice modes?... Answer 351... DMR, D-STAR, and SystemFusion... Question 352... Which of the following factors determine the characteristic impedance of a parallel conductor feed line?... Answer 352... The distance between the centers of the conductors and the radius of the conductors... Question 353... What is the relationship between high standing wave ratio (SWR) and transmission line loss?... Answer 353... High SWR increases loss in a lossy transmission line... Question 354... What is the nominal characteristic impedance of “window line” transmission line?... Answer 354... 450 ohms... Question 355... What causes reflected power at an antenna’s feed point?... Answer 355... A difference between feed line impedance and antenna feed point impedance... Question 356... How does the attenuation of coaxial cable change with increasing frequency?... Answer 356... Attenuation increases... Question 357... In what units is RF feed line loss usually expressed?... Answer 357... Decibels per 100 feet... Question 358... What must be done to prevent standing waves on a feed line connected to an antenna?... Answer 358... The antenna feed point impedance must be matched to the characteristic impedance of the feed line... Question 359... 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 359... 5:1... Question 360... What standing wave ratio results from connecting a 50-ohm feed line to a 200-ohm resistive load?... Answer 360... 4:1... Question 361... What standing wave ratio results from connecting a 50-ohm feed line to a 10-ohm resistive load?... Answer 361... 5:1... Question 362... What is the effect of transmission line loss on SWR measured at the input to the line?... Answer 362... Higher loss reduces SWR measured at the input to the line... Question 363... What is a characteristic of a random-wire HF antenna connected directly to the transmitter?... Answer 363... Station equipment may carry significant RF current... Question 364... 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 364... Slope the radials downward... Question 365... Which of the following best describes the radiation pattern of a quarter-wave ground-plane vertical antenna?... Answer 365... Omnidirectional in azimuth... Question 366... What is the radiation pattern of a dipole antenna in free space in a plane containing the conductor?... Answer 366... It is a figure-eight at right angles to the antenna... Question 367... How does antenna height affect the azimuthal radiation pattern of a horizontal dipole HF antenna?... Answer 367... If the antenna is less than 1/2 wavelength high, the azimuthal pattern is almost omnidirectional... Question 368... Where should the radial wires of a ground-mounted vertical antenna system be placed?... Answer 368... On the surface or buried a few inches below the ground... Question 369... 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 369... It steadily decreases... Question 370... 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 370... It steadily increases... Question 371... Which of the following is an advantage of using a horizontally polarized as compared to a vertically polarized HF antenna?... Answer 371... Lower ground losses... Question 372... What is the approximate length for a 1/2 wave dipole antenna cut for 14.250 MHz?... Answer 372... 33 feet... Question 373... What is the approximate length for a 1/2 wave dipole antenna cut for 3.550 MHz?... Answer 373... 132 feet... Question 374... What is the approximate length for a 1/4 wave monopole antenna cut for 28.5 MHz?... Answer 374... 8 feet... Question 375... Which of the following would increase the bandwidth of a Yagi antenna?... Answer 375... Larger-diameter elements... Question 376... What is the approximate length of the driven element of a Yagi antenna?... Answer 376... 1/2 wavelength... Question 377... How do the lengths of a three-element Yagi reflector and director compare to that of the driven element?... Answer 377... The reflector is longer, and the director is shorter... Question 378... How does antenna gain in dBi compare to gain stated in dBd for the same antenna?... Answer 378... Gain in dBi is 2.15 dB higher... Question 379... What is the primary effect of increasing boom length and adding directors to a Yagi antenna?... Answer 379... Gain increases... Question 380... What does “front-to-back ratio” mean in reference to a Yagi antenna?... Answer 380... The power radiated in the major lobe compared to that in the opposite direction... Question 381... What is meant by the “main lobe” of a directive antenna?... Answer 381... The direction of maximum radiated field strength from the antenna... Question 382... 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 382... Approximately 3 dB higher... Question 383... Which of the following can be adjusted to optimize forward gain, front-to-back ratio, or SWR bandwidth of a Yagi antenna?... Answer 383... The physical length of the boom... Answer 383... The number of elements on the boom... Answer 383... The spacing of each element along the boom... Answer 383... All these choices are correct... Question 384... What is a beta or hairpin match?... Answer 384... A shorted transmission line stub placed at the feed point of a Yagi antenna to provide impedance matching... Question 385... Which of the following is a characteristic of using a gamma match with a Yagi antenna?... Answer 385... It does not require the driven element to be insulated from the boom... Question 386... 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 386... A horizontal dipole placed between 1/10 and 1/4 wavelength above the ground... Question 387... What is the feed point impedance of an end-fed half-wave antenna?... Answer 387... Very high... Question 388... In which direction is the maximum radiation from a VHF/UHF “halo” antenna?... Answer 388... Omnidirectional in the plane of the halo... Question 389... What is the primary function of antenna traps?... Answer 389... To enable multiband operation... Question 390... What is an advantage of vertically stacking horizontally polarized Yagi antennas?... Answer 390... It narrows the main lobe in elevation... Question 391... Which of the following is an advantage of a log-periodic antenna?... Answer 391... Wide bandwidth... Question 392... Which of the following describes a log-periodic antenna?... Answer 392... Element length and spacing vary logarithmically along the boom... Question 393... How does a “screwdriver” mobile antenna adjust its feed point impedance?... Answer 393... By varying the base loading inductance... Question 394... What is the primary use of a Beverage antenna?... Answer 394... Directional receiving for low HF bands... Question 395... In which direction or directions does an electrically small loop (less than 1/3 wavelength in circumference) have nulls in its radiation pattern?... Answer 395... Broadside to the loop... Question 396... Which of the following is a disadvantage of multiband antennas?... Answer 396... They have poor harmonic rejection... Question 397... What is the common name of a dipole with a single central support?... Answer 397... Inverted V... Question 398... What is one way that RF energy can affect human body tissue?... Answer 398... It heats body tissue... Question 399... Which of the following is used to determine RF exposure from a transmitted signal?... Answer 399... Its duty cycle... Answer 399... Its frequency... Answer 399... Its power density... Answer 399... All these choices are correct... Question 400... How can you determine that your station complies with FCC RF exposure regulations?... Answer 400... By calculation based on FCC OET Bulletin 65... Answer 400... By calculation based on computer modeling... Answer 400... By measurement of field strength using calibrated equipment... Answer 400... All these choices are correct... Question 401... What does “time averaging” mean when evaluating RF radiation exposure?... Answer 401... The total RF exposure averaged over a certain period... Question 402... 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 402... Take action to prevent human exposure to the excessive RF fields... Question 403... What must you do if your station fails to meet the FCC RF exposure exemption criteria?... Answer 403... Perform an RF Exposure Evaluation in accordance with FCC OET Bulletin 65... Question 404... What is the effect of modulation duty cycle on RF exposure?... Answer 404... A lower duty cycle permits greater power levels to be transmitted... Question 405... Which of the following steps must an amateur operator take to ensure compliance with RF safety regulations?... Answer 405... Perform a routine RF exposure evaluation and prevent access to any identified high exposure areas... Question 406... What type of instrument can be used to accurately measure an RF field strength?... Answer 406... A calibrated field strength meter with a calibrated antenna... Question 407... 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 407... Take precautions to ensure that the antenna cannot be pointed in their direction when they are present... Question 408... What precaution should be taken if you install an indoor transmitting antenna?... Answer 408... Make sure that MPE limits are not exceeded in occupied areas... Question 409... What stations are subject to the FCC rules on RF exposure?... Answer 409... All stations with a time-averaged transmission of more than one milliwatt... Question 410... Which wire or wires in a four-conductor 240 VAC circuit should be attached to fuses or circuit breakers?... Answer 410... Only the hot wires... Question 411... 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 411... AWG number 12... Question 412... Which size of fuse or circuit breaker would be appropriate to use with a circuit that uses AWG number 14 wiring?... Answer 412... 15 amperes... Question 413... Where should the station’s lightning protection ground system be located?... Answer 413... Outside the building... Question 414... Which of the following conditions will cause a ground fault circuit interrupter (GFCI) to disconnect AC power?... Answer 414... Current flowing from one or more of the hot wires directly to ground... Question 415... Which of the following is covered by the National Electrical Code?... Answer 415... Electrical safety of the station... Question 416... Which of these choices should be observed when climbing a tower using a safety harness?... Answer 416... Confirm that the harness is rated for the weight of the climber and that it is within its allowable service life... Question 417... What should be done before climbing a tower that supports electrically powered devices?... Answer 417... Make sure all circuits that supply power to the tower are locked out and tagged... Question 418... Which of the following is true of an emergency generator installation?... Answer 418... The generator should be operated in a well-ventilated area... Question 419... Which of the following is a danger from lead-tin solder?... Answer 419... Lead can contaminate food if hands are not washed carefully after handling the solder... Question 420... Which of the following is required for lightning protection ground rods?... Answer 420... They must be bonded together with all other grounds... Question 421... What is the purpose of a power supply interlock?... Answer 421... To ensure that dangerous voltages are removed if the cabinet is opened... Question 422... Where should lightning arrestors be located?... Answer 422... Where the feed lines enter the building...