Technician Licensing ClassTechnician Licensing Class“Chapter 5”“Chapter 5”
Valid dates:
July 1, 2010 – June 30, 2014
Amateur Radio EquipmentAmateur Radio Equipment
22
Chapter 5 ContentsChapter 5 Contents
Transmitters and ReceiversTransmitters and Receivers
Digital CommunicationsDigital Communications
Power Supplies and BatteriesPower Supplies and Batteries
Radio Frequency Interference (RFI)Radio Frequency Interference (RFI)
RF GroundingRF Grounding
33
Transmitters and ReceiversTransmitters and Receivers
Used to be separate unitsUsed to be separate units Still can beStill can be Transceivers (containing both Transceivers (containing both
transmitter and receiver more transmitter and receiver more common place now)common place now)
AbbreviationsAbbreviations• Tx Rx or Rcvr XCVRTx Rx or Rcvr XCVR
44
Transmitters and ReceiversTransmitters and Receivers
Selecting Band, Frequency and ModeSelecting Band, Frequency and Mode
Amateur radio has bands rather than Amateur radio has bands rather than channels other than on 60 meters)channels other than on 60 meters)
AM and SSB can be more than speech (CW AM and SSB can be more than speech (CW datadata
FM can be voice or dataFM can be voice or data
55
Amateur Radio BandsAmateur Radio Bands
HFHF• 160160 1.8 MHz1.8 MHz• 8080 3.5 MHz3.5 MHz• 60*60* 5 Mhz5 Mhz• 4040 7 MHz7 MHz• 3030 10 Mhz10 Mhz• 2020 14 Mhz14 Mhz• 1717 18 Mhz18 Mhz• 1515 21 Mhz21 Mhz• 1212 24 Mhz24 Mhz• 1010 28 Mhz28 Mhz
VHFVHF• 66 50 Mhz50 Mhz• 22 144 Mhz144 Mhz• 1¼1¼ 222 Mhz222 Mhz
UHFUHF• 70 cm70 cm 440 Mhz440 Mhz• 33 cm33 cm 902 Mhz902 Mhz• 23 cm23 cm 1240 1240
MhzMhz• 13 cm13 cm 2300 2300
MhzMhz
66
Control and Function KeysControl and Function Keys
Can be separate or same keyCan be separate or same key Control keys typically directly control Control keys typically directly control
the radiothe radio Function keys are more like menu Function keys are more like menu
and are used to select and set and are used to select and set functions and parameters for the functions and parameters for the radio’s operationradio’s operation
77
Transmitters and ReceiversTransmitters and Receivers
Transmitter FunctionsTransmitter Functions
88
Transmitter FunctionsTransmitter Functions
RF Power Control RF Power Control Microphone GainMicrophone Gain Speech Compressor/ProcessorSpeech Compressor/Processor PEP (Peak Envelope Power) SSB & AMPEP (Peak Envelope Power) SSB & AM ALCALC Band and frequency tuningBand and frequency tuning
99
Transmitter FunctionsTransmitter Functions
Spurious SignalsSpurious Signals• Turn down microphone gainTurn down microphone gain• Turn down compressor/speech Turn down compressor/speech
processorprocessor• Back away from microphoneBack away from microphone• ALCALC• Proper Tuning if not solid state Proper Tuning if not solid state
equipmentequipment
1010
Transmitter FunctionsTransmitter Functions
MicrophonesMicrophones• HandHand• DeskDesk• BoomBoom• HeadsetHeadset• ThroatThroat
VOX vs ManualVOX vs Manual
1111
Transmitter FunctionsTransmitter Functions
KeysKeys• ManualManual
Straight KeyStraight Key
• Semi-AutomaticSemi-Automatic Bug Dits automatic Dahs automaticBug Dits automatic Dahs automatic
• Automatic/ElectronicAutomatic/Electronic Dits and Dahs both automatic and self Dits and Dahs both automatic and self
completingcompleting Single and double lever typesSingle and double lever types Iambic and non iambicIambic and non iambic
1212
Receiver FunctionsReceiver Functions
AF and RF GainAF and RF Gain Bandwidth (filters)Bandwidth (filters) Band and frequency tuningBand and frequency tuning AttenuatorAttenuator DSPDSP Automatic Gain Control (AGC)Automatic Gain Control (AGC) RIT Receiver Incremental Tuning RIT Receiver Incremental Tuning
(Clarifier)(Clarifier)• Allows rx tuning off of tx frequency in xcvrAllows rx tuning off of tx frequency in xcvr
1313
Modern TransceiverModern Transceiver
1414
Digital Signal Processing (DSP)Digital Signal Processing (DSP)
Noise ReductionNoise Reduction Variable signal filteringVariable signal filtering Automatic notching filteringAutomatic notching filtering Audio contouring on tx and rxAudio contouring on tx and rx ShiftShift WidthWidth
1515
Handheld TranceiversHandheld Tranceivers
Single Band, Dual, Tri, and quad Single Band, Dual, Tri, and quad bandband
Built in microphone and speakers but Built in microphone and speakers but jacks for externaljacks for external
MemoriesMemories Push to Talk PTTPush to Talk PTT Rubber Duck antennaRubber Duck antenna Better antennasBetter antennas Connect to outside antennasConnect to outside antennas
1616
DIGITAL COMMUNICATIONSDIGITAL COMMUNICATIONS
Need Modem / TNCNeed Modem / TNC
Advantages Digital Signal ProcessingAdvantages Digital Signal Processing
RedundancyRedundancy
Error CorrectionError Correction
Allow easy reception of very weak signalsAllow easy reception of very weak signals
1717
Amateur Digital ModesAmateur Digital Modes
RTTYRTTY PACTOR & WINMORPACTOR & WINMOR PSK31 & MFSKPSK31 & MFSK OliviaOlivia DominoDomino VHF & UHF Packet and Winlink 2000VHF & UHF Packet and Winlink 2000
1818
Errors in Digital DataErrors in Digital Data
Errors measured in Bit Error Rate Errors measured in Bit Error Rate (BER)(BER)
Parity bitsParity bits Forward Error CorrectionForward Error Correction
1919
Packet & Packet NetworksPacket & Packet Networks
Use FSK (Frequency Shift Keying)Use FSK (Frequency Shift Keying) Can run automaticallyCan run automatically ARQ Automatic Repeat RequestARQ Automatic Repeat Request AX.25 protocolAX.25 protocol Bulletin BoardsBulletin Boards MessagesMessages Or direct hands on communicationsOr direct hands on communications Think long lists of data to be Think long lists of data to be
transmittedtransmitted
202020
T8D:T8D: Non-voice communications; image data, digital modes CW, Non-voice communications; image data, digital modes CW,
packet,PSK31packet,PSK31
• T8D8T8D8 Packet transmissions may include: Packet transmissions may include: A check sum which permits error detection;A check sum which permits error detection; A header which contains the call sign of the station to A header which contains the call sign of the station to
which the information is being sent;which the information is being sent; Automatic repeat request in case of error.Automatic repeat request in case of error.
Laptop, TNC, and Handheld comprise
Packet Station.
2121
Keyboard-to-KeyboardKeyboard-to-Keyboard
Most Digital Modes including RTTY Most Digital Modes including RTTY and CWand CW
CW faster than you can send or CW faster than you can send or receivereceive
PSK31, Olivia, Domino, Many othersPSK31, Olivia, Domino, Many others
2222
T8D:T8D: Non-voice communications; image data, digital modes CW, packet, Non-voice communications; image data, digital modes CW, packet,
PSK31PSK31
• T8D7T8D7 PSK31 is a low-rate data transmission mode. PSK31 is a low-rate data transmission mode. PSK-31 transmission rate is about normal typing speed.PSK-31 transmission rate is about normal typing speed. PSK is a remarkable digital mode that slices through interference and PSK is a remarkable digital mode that slices through interference and
gets message across sometimes to the moon and back.gets message across sometimes to the moon and back.
You can connect a PSK-31 and RTTY data reader to your radio to decode
messages
2323
APRSAPRS
Automatic Position Reporting SystemAutomatic Position Reporting System
/www.ui-view.org/findu.htm/www.ui-view.org/findu.htm
2424
APRSAPRS
2525
APRS – www.findu.comAPRS – www.findu.com
2626
WinlinkWinlink
Permits sending email over the air on Permits sending email over the air on HF, VHF or UHFHF, VHF or UHF
2727
Setting up for digital modesSetting up for digital modes
Page 5-12 of ManualPage 5-12 of Manual Transceiver connects to Transceiver connects to
• PC, audio interface, and TNCPC, audio interface, and TNC
2828
GatewaysGateways
PAGE 5-12PAGE 5-12 Usually forward messagesUsually forward messages Some provide Internet ConnectivitySome provide Internet Connectivity
2929
T4A06T4A06 Which of the following would be Which of the following would be connected between a connected between a
transceiver and transceiver and computer in a computer in a packet radio station?packet radio station?
A.A. TransmatchTransmatch
B.B. MixerMixer
C.C. Terminal node controllerTerminal node controller
D.D. AntennaAntenna
3030
T4A07T4A07 How is the computer’s sound card How is the computer’s sound card used used when conducting digital when conducting digital communications communications using a computer?using a computer?
A.A. The sound card communicates between The sound card communicates between the computer CPU and the video displaythe computer CPU and the video display
B.B. The sound card records the audio The sound card records the audio frequency for video displayfrequency for video display
C.C. The sound card provides audio to the The sound card provides audio to the microphone input and converts received microphone input and converts received audio to digital formaudio to digital form
D.D. All of these choices are correctAll of these choices are correct
3131
T8C11T8C11 What name is given to an amateur What name is given to an amateur radio radio station that is used to connect station that is used to connect other other amateur stations to the amateur stations to the Internet?Internet?
A.A. A gatewayA gateway
B.B. A repeaterA repeater
C.C. A digipeaterA digipeater
D.D. A beaconA beacon
3232
T8D02T8D02 What does the term APRS mean?What does the term APRS mean?
A.A. Automatic Position Reporting Automatic Position Reporting SystemSystem
B.B. Associated Public Radio StationAssociated Public Radio Station
C.C. Auto Planning Radio Set-upAuto Planning Radio Set-up
D.D. Advanced Polar Radio SystemAdvanced Polar Radio System
3333
T8D03T8D03 Which of the following is normally Which of the following is normally used used when sending automatic location when sending automatic location reports reports via amateur radio?via amateur radio?
A.A. A connection to the vehicle A connection to the vehicle speedometerspeedometer
B.B. A WWV receiverA WWV receiver
C.C. A connection to a broadcast FM A connection to a broadcast FM sub-carrier receiversub-carrier receiver
D.D. A Global Positioning System A Global Positioning System receiverreceiver
3434
T8D06T8D06 What does the abbreviation What does the abbreviation PSK PSK mean?mean?
A.A. Pulse Shift KeyingPulse Shift Keying
B.B. Phase Shift KeyingPhase Shift Keying
C.C. Packet Short KeyingPacket Short Keying
D.D. Phased Slide KeyingPhased Slide Keying
3535
T8D07T8D07 What is PSK31?What is PSK31?
A.A. A high-rate data transmission modeA high-rate data transmission mode
B.B. A method of reducing noise A method of reducing noise interference to FM signalsinterference to FM signals
C.C. A method of compressing digital A method of compressing digital television signaltelevision signal
D.D. A low-rate data transmission mode A low-rate data transmission mode
3636
T8D08T8D08 Which of the following may be Which of the following may be included in included in packet transmissions?packet transmissions?
A.A. A check sum which permits error A check sum which permits error detectiondetection
B.B. A header which contains the call sign A header which contains the call sign of the station to which the information of the station to which the information is being sentis being sent
C.C. Automatic repeat request in case of Automatic repeat request in case of errorerror
D.D. All of these choices are correct All of these choices are correct
3737
POWER SUPPLIES & POWER SUPPLIES & BATTERIESBATTERIES
3838
Power SuppliesPower Supplies
Convert AC current to voltages needed by Convert AC current to voltages needed by equipmentequipment
Can be internal or externalCan be internal or external Wall wartsWall warts Power SuppliesPower Supplies
• Analog or LinearAnalog or Linear• SwitchingSwitching• Regulated to keep voltage constant with and Regulated to keep voltage constant with and
without loadwithout loadRating must be at least as much as required by Rating must be at least as much as required by
the equipmentthe equipment
3939
Mobile Power WiringMobile Power Wiring
Fuse both Positive and Negative LeadsFuse both Positive and Negative Leads Connect negative lead to battery Connect negative lead to battery
terminalterminal Use grommets when wire passes Use grommets when wire passes
through bulkhead or firewallthrough bulkhead or firewall Do not assume all metal is grounded. Do not assume all metal is grounded.
Lots are connected with plasticLots are connected with plastic Keep leads short and use heavy cableKeep leads short and use heavy cable Alternator whine can be removed with Alternator whine can be removed with
DC power filter at your radioDC power filter at your radio
4040
T0A: T0A: AC power circuits; hazardous voltages, fuses and AC power circuits; hazardous voltages, fuses and circuit breakers, circuit breakers, grounding, lightning protection, battery grounding, lightning protection, battery
safety, electrical code compliance.safety, electrical code compliance.
• T0A4T0A4 The purpose of a fuse in an electrical circuit is to interrupt The purpose of a fuse in an electrical circuit is to interrupt power in case of overload.power in case of overload.
Place the fuses as close to the battery as possible
Fuses
Slow-Blow fuseAutomobile fuse
4141
Generators & InvertersGenerators & Inverters
Generate power – usually 120 0r 240 Generate power – usually 120 0r 240 VACVAC
Inverters – Turn DC power into AC Inverters – Turn DC power into AC powerpower
Voltage regulation very important to Voltage regulation very important to protect equipment from surgesprotect equipment from surges
4242
T4A03T4A03 Which is a good reason to use a Which is a good reason to use a regulated regulated power supply for power supply for communications communications equipment?equipment?
A.A. It prevents voltage fluctuations It prevents voltage fluctuations from reaching sensitive circuitsfrom reaching sensitive circuits
B.B. A regulated power supply has FCC A regulated power supply has FCC approvalapproval
C.C. A fuse or circuit breaker regulates A fuse or circuit breaker regulates the powerthe power
D.D. Power consumption is Power consumption is independent of loadindependent of load
4343
T4A10T4A10 What is the source of a high-What is the source of a high-pitched whine pitched whine that varies with that varies with engine speed in a mobile engine speed in a mobile transceiver’s receive audio?transceiver’s receive audio?
A.A. The ignition systemThe ignition system
B.B. The alternatorThe alternator
C.C. The electric fuel pumpThe electric fuel pump
D.D. Anti-lock braking system Anti-lock braking system controllerscontrollers
4444
T4A11T4A11 Where should a mobile Where should a mobile transceiver’s transceiver’s power negative power negative connection be made?connection be made?
A.A. At the battery or engine block At the battery or engine block ground strapground strap
B.B. At the antenna mountAt the antenna mount
C.C. To any metal part of the vehicleTo any metal part of the vehicle
D.D. Through the transceiver’s Through the transceiver’s mounting bracketmounting bracket
4545
T5A06T5A06 How much voltage does a mobile How much voltage does a mobile transceiver usually require?transceiver usually require?
A.A. About 12 voltsAbout 12 volts
B.B. About 30 voltsAbout 30 volts
C.C. About 120 voltsAbout 120 volts
D.D. About 240 voltsAbout 240 volts
4646
T6D05T6D05 What type of circuit controls the What type of circuit controls the amount of amount of voltage from a power voltage from a power supply?supply?
A.A. RegulatorRegulator
B.B. OscillatorOscillator
C.C. FilterFilter
D.D. Phase inverterPhase inverter
4747
T7B09T7B09 What could be happening if another What could be happening if another operator reports a variable operator reports a variable
high-pitched high-pitched whine on the audio from whine on the audio from your mobile transmitter?your mobile transmitter?
A.A. Your microphone is picking up noise Your microphone is picking up noise from an open windowfrom an open window
B.B. You have the volume on your receiver You have the volume on your receiver set too highset too high
C.C. You need to adjust your squelch You need to adjust your squelch controlcontrol
D.D. Noise on the vehicle’s electrical Noise on the vehicle’s electrical system is being transmitted along system is being transmitted along with your speech audiowith your speech audio
4848
BatteriesBatteries
DisposableDisposable• Used once and disposed of cannot be Used once and disposed of cannot be
rechargedrecharged
Rechargeable or SecondaryRechargeable or Secondary• Chemical reaction reversed to chargeChemical reaction reversed to charge
StorageStorage• Also rechargeable used for long-term energy Also rechargeable used for long-term energy
storagestorage
4949
Handheld Radio BatteriesHandheld Radio Batteries
Some radios can use disposable Some radios can use disposable batteriesbatteries
Most use custom packs of rechargeablesMost use custom packs of rechargeables• NiCad (Nickel Cadmium)NiCad (Nickel Cadmium)• NiMH (Nickel-metal hydride)NiMH (Nickel-metal hydride)• Li-ion (Lithium Ion)Li-ion (Lithium Ion)
Li-ion highest energy capacity NiMH and Li-ion highest energy capacity NiMH and NiCad next.NiCad next.
Most HTs come with chargers to charge Most HTs come with chargers to charge batteriesbatteries
Memory in NiCad batteriesMemory in NiCad batteries
5050
T6A10T6A10 What is the nominal voltage of a What is the nominal voltage of a fully fully charged nickel-cadmium cell?charged nickel-cadmium cell?
A.A. 1.0 volts1.0 volts
B.B. 1.2 volts1.2 volts
C.C. 1.5 volts1.5 volts
D.D. 2.2 volts2.2 volts
5151
T6A11T6A11 Which battery type is not Which battery type is not
rechargeable?rechargeable? A.A. Nickel-cadmiumNickel-cadmium
B.B. Carbon-zincCarbon-zinc
C.C. Lead-acidLead-acid
D.D. Lithium-ionLithium-ion
5252
T0A08T0A08 What is one way to recharge a 12-What is one way to recharge a 12-volt lead-volt lead- acid station battery if the acid station battery if the commercial commercial power is out?power is out?
A.A. Cool the battery in ice for several Cool the battery in ice for several hourshours
B.B. Add acid to the batteryAdd acid to the battery
C.C. Connect the battery to a car's battery Connect the battery to a car's battery and run the engineand run the engine
D.D. All of these choices are correctAll of these choices are correct
5353
T0A09T0A09 What kind of hazard is presented What kind of hazard is presented by a by a conventional 12-volt storage conventional 12-volt storage battery?battery?
A.A. It emits ozone which can be It emits ozone which can be harmful to the atmosphereharmful to the atmosphere
B.B. Shock hazard due to high voltageShock hazard due to high voltage
C.C. Explosive gas can collect if not Explosive gas can collect if not properly ventedproperly vented
D.D. All of these choices are correctAll of these choices are correct
5454
T0A10T0A10 What can happen if a lead-acid What can happen if a lead-acid storage battery is charged storage battery is charged
or or discharged too quickly?discharged too quickly?
A.A. The battery could overheat and The battery could overheat and give off flammable gas or explodegive off flammable gas or explode
B.B. The voltage can become reversedThe voltage can become reversed
C.C. The “memory effect” will reduce The “memory effect” will reduce the capacity of the batterythe capacity of the battery
D.D. All of these choices are correctAll of these choices are correct
5555
RADIO FREQUENCY RADIO FREQUENCY INTERFERENCE (RFI)INTERFERENCE (RFI)
Getting more common placeGetting more common place Can be amateur radio interfering Can be amateur radio interfering
with other deviceswith other devices OROR Other devices interfering with Other devices interfering with
amateur radio operationamateur radio operation
5656
FiltersFilters
Very important and useful in Very important and useful in resolving Radio Frequency resolving Radio Frequency InterferenceInterference
AC power line filtersAC power line filters
RF choke/common-mode ferrite RF choke/common-mode ferrite filtersfilters
5757
Direct DetectionDirect Detection
RF gets into devices and is turned RF gets into devices and is turned into voltages that cause interferenceinto voltages that cause interference
Common with phonesCommon with phones Low pass filter at wired phone’s Low pass filter at wired phone’s
modular jackmodular jack Chokes and ferrite on speaker cordsChokes and ferrite on speaker cords
5858
OverloadOverload
““Fundamental OverloadFundamental Overload• Strong signal just gets in and interferes Strong signal just gets in and interferes
with electronics because of its strengthwith electronics because of its strength High Pass Filter at ReceiverHigh Pass Filter at Receiver Ferrite on device’s power cordFerrite on device’s power cord Shielding at ReceiverShielding at Receiver If tx & rx frequencies close – notch If tx & rx frequencies close – notch
filter or resolution not possiblefilter or resolution not possible
5959
Harmonics & Spurious EmissionsHarmonics & Spurious Emissions
Low Pass Filters on TransmitterLow Pass Filters on Transmitter Can be in-band interference and Can be in-band interference and
cannot be filtered out at receivercannot be filtered out at receiver
6060
Noise SourcesNoise Sources
Electrical equipment, lights, switchesElectrical equipment, lights, switches Cracked or dirty insulatorsCracked or dirty insulators Ignition noise from enginesIgnition noise from engines Alternator whineAlternator whine Switching Power SuppliesSwitching Power Supplies Computer, peripheral & network Computer, peripheral & network
equipmentequipment
6161
Unknown SignalsUnknown Signals
Track with a radio when possibleTrack with a radio when possible Radio Direction Finding (RDF)Radio Direction Finding (RDF)
• TriangulationTriangulation• Get azimuth bearing from three or more Get azimuth bearing from three or more
locationslocations• Plot on mapPlot on map• Interference where lines crossInterference where lines cross
6262
GuidelinesGuidelines
Make sure your station is in good Make sure your station is in good working orderworking order
Make sure you do not interfere with Make sure you do not interfere with anything in your homeanything in your home
Take care of any devices in your Take care of any devices in your home that cause interferencehome that cause interference
6363
GuidelinesGuidelines
Be diplomatic and good neighborBe diplomatic and good neighbor
Put yourself in the other person’s Put yourself in the other person’s positionposition
Demonstrate where possibleDemonstrate where possible
Get help from other hamsGet help from other hams
6464
FCC Part 15 RulesFCC Part 15 Rules
FCC sanctioned unlicensed operation FCC sanctioned unlicensed operation of certain low powered devicesof certain low powered devices
NIB to licensed servicesNIB to licensed services Must accept interference from Must accept interference from
licensed services and other Part 15 licensed services and other Part 15 devicesdevices
656565
T7B: T7B: Common transmitter and receiver problems; Common transmitter and receiver problems; symptoms of overload and symptoms of overload and overdrive, distortion, interference, overdrive, distortion, interference,
over and under modulation, RF feedback, over and under modulation, RF feedback, off frequency signals; off frequency signals; fading and noise; problems with digital fading and noise; problems with digital communications communications
interfacesinterfaces
• T7B8T7B8 If a "Part 15" device in your neighbor’s home is causing If a "Part 15" device in your neighbor’s home is causing harmful interference to your amateur station:harmful interference to your amateur station:
Work with your neighbor to identify the offending device; Work with your neighbor to identify the offending device; Politely inform your neighbor about the rules that require Politely inform your neighbor about the rules that require
him to stop using the device if it causes interference; him to stop using the device if it causes interference; Check your station and make sure it meets the standards Check your station and make sure it meets the standards
of good amateur practice.of good amateur practice.
A simple snap-on choke filter like this
one can help resolve harmful
interference problems on Part
15 devices.
6666
T4A04T4A04 Where must a filter be installed to Where must a filter be installed to reduce reduce harmonic emissions?harmonic emissions?
A.A. Between the transmitter and the antennaBetween the transmitter and the antenna
B.B. Between the receiver and the transmitterBetween the receiver and the transmitter
C.C. At the station power supplyAt the station power supply
D.D. At the microphoneAt the microphone
6767
T4A05T4A05 What type of filter should be connected What type of filter should be connected to a TV to a TV receiver as the first step in trying to receiver as the first step in trying to prevent RF prevent RF overload from a nearby 2 overload from a nearby 2 meter transmitter?meter transmitter?
A.A. Low-pass filterLow-pass filter
B.B. High-pass filterHigh-pass filter
C.C. Band-pass filterBand-pass filter
D.D. Band-reject filterBand-reject filter
6868
T4A09T4A09 Which would you use to reduce RF Which would you use to reduce RF current current flowing on the shield of an flowing on the shield of an
audio cable?audio cable? A.A. Band-pass filterBand-pass filter
B.B. Low-pass filterLow-pass filter
C.C. PreamplifierPreamplifier
D.D. Ferrite chokeFerrite choke
6969
T7B02T7B02 What is meant by fundamental What is meant by fundamental overload in overload in reference to a receiver?reference to a receiver?
A.A. Too much voltage from the power Too much voltage from the power supplysupply
B.B. Too much current from the power Too much current from the power supplysupply
C.C. Interference caused by very strong Interference caused by very strong signalssignals
D.D. Interference caused by turning the Interference caused by turning the volume up too highvolume up too high
7070
T7B03T7B03 Which of the following may be a Which of the following may be a cause of cause of radio frequency radio frequency interference?interference?
A.A. Fundamental overloadFundamental overload
B.B. HarmonicsHarmonics
C.C. Spurious emissionsSpurious emissions
D.D. All of these choices are correctAll of these choices are correct
7171
T7B04T7B04 What is the most likely cause of What is the most likely cause of interference to a non-interference to a non-
cordless telephone cordless telephone from a nearby from a nearby transmitter?transmitter?
A.A. Harmonics from the transmitterHarmonics from the transmitter
B.B. The telephone is inadvertently The telephone is inadvertently acting as a radio receiveracting as a radio receiver
C.C. Poor station groundingPoor station grounding
D.D. Improper transmitter adjustmentImproper transmitter adjustment
7272
T7B05T7B05 What is a logical first step when What is a logical first step when attempting attempting to cure a radio frequency to cure a radio frequency interference interference problem in a nearby problem in a nearby telephone?telephone?
A.A. Install a low-pass filter at the transmitterInstall a low-pass filter at the transmitter
B.B. Install a high-pass filter at the transmitterInstall a high-pass filter at the transmitter
C.C. Install an RF filter at the telephoneInstall an RF filter at the telephone
D.D. Improve station groundingImprove station grounding
7373
T7B06T7B06 What should you do first if someone What should you do first if someone tells tells you that your station’s you that your station’s transmissions are transmissions are interfering interfering with their radio or TV reception?with their radio or TV reception?
A.A. Make sure that your station is functioning properly and Make sure that your station is functioning properly and that it does not cause interference to your own that it does not cause interference to your own televisiontelevision
B.B. Immediately turn off your transmitter and contact the Immediately turn off your transmitter and contact the nearest FCC office for assistancenearest FCC office for assistance
C.C. Tell them that your license gives you the right to Tell them that your license gives you the right to transmit and nothing can be done to reduce the transmit and nothing can be done to reduce the interferenceinterference
D.D. Continue operating normally because your equipment Continue operating normally because your equipment cannot possibly cause any interferencecannot possibly cause any interference
7474
T7B07T7B07 Which of the following may be Which of the following may be useful useful in correcting a radio in correcting a radio frequency frequency interference interference problem?problem?
A.A. Snap-on ferrite chokesSnap-on ferrite chokes
B.B. Low-pass and high-pass filtersLow-pass and high-pass filters
C.C. band-reject and band-pass filtersband-reject and band-pass filters
D.D. All of these choices are correctAll of these choices are correct
7575
T7B08T7B08 What should you do if a "Part 15" What should you do if a "Part 15" device in device in your neighbor’s home is your neighbor’s home is causing harmful causing harmful interference to your interference to your amateur station?amateur station?
A.A. Work with your neighbor to identify the Work with your neighbor to identify the offending deviceoffending device
B.B. Politely inform your neighbor about the Politely inform your neighbor about the rules that require him to stop using the rules that require him to stop using the device if it causes interferencedevice if it causes interference
C.C. Check your station and make sure it Check your station and make sure it meets the standards of good amateur meets the standards of good amateur practicepractice
D.D. All of these choices are correctAll of these choices are correct
7676
RF GROUNDINGRF GROUNDING
Electrical and RF ground not always Electrical and RF ground not always samesame
Use short lengths of heavy cable or flat Use short lengths of heavy cable or flat strap to ground all equipment to strap to ground all equipment to ground rodground rod
Flat Strap Is BestFlat Strap Is Best
7777
RF GROUNDINGRF GROUNDING
Bad RF ground can result in RF current Bad RF ground can result in RF current affecting sensitive audio or other affecting sensitive audio or other equipmentequipment
Can cause shock or RF burnsCan cause shock or RF burns
RF feedback via microphone cable can RF feedback via microphone cable can distort your signaldistort your signal
7878
RF GROUNDINGRF GROUNDING
7979
T4A08T4A08 Which type of conductor is best to Which type of conductor is best to use for use for RF grounding?RF grounding?
A.A. Round stranded wire Round stranded wire
B.B. Round copper-clad steel wireRound copper-clad steel wire
C.C. Twisted-pair cableTwisted-pair cable
D.D. Flat strapFlat strap
8080
T7B11T7B11 What is a symptom of RF feedback What is a symptom of RF feedback in ain a transmitter or transceiver? transmitter or transceiver?
A.A. Excessive SWR at the antenna Excessive SWR at the antenna connectionconnection
B.B. The transmitter will not stay on the The transmitter will not stay on the desired frequencydesired frequency
C.C. Reports of garbled, distorted, or Reports of garbled, distorted, or unintelligible transmissionsunintelligible transmissions
D.D. Frequent blowing of power supply Frequent blowing of power supply fusesfuses