Technician License Class Gordon West Technician Class Manual Pages 160-170 Electrical & RF Safety Presented by Heart Of Texas Amateur Radio Club (HOTARC)

Technician Technician License License ClassClass

Gordon West Gordon West Technician Class Technician Class

ManualManualPages 160-170Pages 160-170

Electrical & RF SafetyElectrical & RF Safety

Presented byPresented by

Heart Of Texas Heart Of Texas Amateur Radio Amateur Radio

ClubClub(HOTARC)(HOTARC)

Electrical and RF SafetyElectrical and RF Safety 22

Electrical SafetyElectrical SafetyVoltages as low as 30 volts can Voltages as low as 30 volts can cause a dangerous electrical shock.cause a dangerous electrical shock.

Current as low as 100 milliamperes Current as low as 100 milliamperes can cause death.can cause death.

A power supply can be an electric shock hazard A power supply can be an electric shock hazard even when turned off due to large charge stored even when turned off due to large charge stored in filter capacitors.in filter capacitors.

When installing an emergency disconnect switch When installing an emergency disconnect switch at your station the most important consideration at your station the most important consideration is to make sure everyone knows where it is and is to make sure everyone knows where it is and how to use it.how to use it.


AC WiringAC WiringTo guard against electrical shock at your To guard against electrical shock at your station:station:

Always use 3-wire cords and Always use 3-wire cords and plugs for all AC powered equipment.plugs for all AC powered equipment.

Connect all AC powered station Connect all AC powered station equipment to a common ground.equipment to a common ground.

Use a ground-fault interrupter Use a ground-fault interrupter at each electrical outlet.at each electrical outlet.


T0A01 T0A01 (pg 160)(pg 160)

What is a commonly accepted value for the What is a commonly accepted value for the lowest voltage that can cause a dangerous lowest voltage that can cause a dangerous electric shock?electric shock?A.A. 12 volts12 volts

B.B. 30 volts30 voltsC.C. 120 volts120 volts

D.D. 300 volts300 volts


T0A10 T0A10 (pg 160)(pg 160)

What kind of hazard is presented by a What kind of hazard is presented by a conventional 12-volt storage battery?conventional 12-volt storage battery?A.A. It contains dangerous acid that can spill and It contains dangerous acid that can spill and

cause injurycause injury

B.B. Short circuits can damage wiring and possibly Short circuits can damage wiring and possibly cause a firecause a fire

C.C. Explosive gas can collect if not properly ventedExplosive gas can collect if not properly vented

D.D. All of these answers are correctAll of these answers are correct


T0A11 T0A11 (pg 160)(pg 160)

What can happen if a storage battery is What can happen if a storage battery is charged or discharged too quickly?charged or discharged too quickly?A.A. The battery could overheat and give off The battery could overheat and give off

dangerous gas or explodedangerous gas or explode

B.B. The terminal voltage will oscillate rapidlyThe terminal voltage will oscillate rapidly

C.C. The warranty will be voidedThe warranty will be voided

D.D. The voltage will be reversedThe voltage will be reversed


T0A06 T0A06 (pg 160)(pg 160)

What is a good way to guard against What is a good way to guard against electrical shock at your station?electrical shock at your station?A.A. Use 3-wire cords and plugs for all AC powered Use 3-wire cords and plugs for all AC powered

equipmentequipment

B.B. Connect all AC powered station equipment to Connect all AC powered station equipment to a common grounda common ground

C.C. Use a ground-fault interrupter at each Use a ground-fault interrupter at each electrical outletelectrical outlet



T0A03 T0A03 (pg 161)(pg 161)

What is connected to What is connected to the green wire in a the green wire in a three-wire electrical three-wire electrical plug?plug?

A.A. NeutralNeutral

B.B. HotHot

C.C. GroundGround

D.D. The white wireThe white wire


T0A02 T0A02 (pg 161)(pg 161)

What is the lowest amount of electrical What is the lowest amount of electrical current flowing through the human body that current flowing through the human body that is likely to cause death?is likely to cause death?A.A. 10 microamperes10 microamperes

B.B. 100 milliamperes100 milliamperes

C.C. 10 amperes10 amperes

D.D. 100 amperes100 amperes


T0A13 T0A13 (pg 161)(pg 161)

What kind of hazard might exist in a power What kind of hazard might exist in a power supply when it is turned off and supply when it is turned off and disconnected?disconnected?A.A. Static electricity could damage the grounding Static electricity could damage the grounding

systemsystem

B.B. Circulating currents inside the transformer Circulating currents inside the transformer might cause damagemight cause damage

C.C. The fuse might blow if you remove the coverThe fuse might blow if you remove the cover

D.D. You might receive an electric shock from You might receive an electric shock from stored charge in large capacitorsstored charge in large capacitors


T0A07 T0A07 (pg 161)(pg 161)

What is the most important thing to consider What is the most important thing to consider when installing an emergency disconnect when installing an emergency disconnect switch at your station?switch at your station?A.A. It must always be as near to the operator as It must always be as near to the operator as

possiblepossible

B.B. It must always be as far away from the operator It must always be as far away from the operator as possibleas possible

C.C. Everyone should know where it is and how to Everyone should know where it is and how to use ituse it

D.D. It should be installed in a metal box to prevent It should be installed in a metal box to prevent tamperingtampering


T0A04 T0A04 (pg 162)(pg 162)

What is the purpose of a fuse What is the purpose of a fuse in an electrical circuit?in an electrical circuit?A.A. To make sure enough power To make sure enough power

reaches the circuitreaches the circuit

B.B. To interrupt power in case of overloadTo interrupt power in case of overload

C.C. To prevent television interferenceTo prevent television interference

D.D. To prevent shocksTo prevent shocks


T0A05 T0A05 (pg 162)(pg 162)

What might happen if you What might happen if you install a 20-ampere fuse in install a 20-ampere fuse in your transceiver in the place your transceiver in the place of a 5-ampere fuse?of a 5-ampere fuse?A.A. The larger fuse would better protect your The larger fuse would better protect your

transceiver from using too much currenttransceiver from using too much current

B.B. The transceiver will run coolerThe transceiver will run cooler

C.C. Excessive current could cause a fireExcessive current could cause a fire

D.D. The transceiver would not be able to produce The transceiver would not be able to produce as much RF outputas much RF output


LightningLightningWhen a lightning storm When a lightning storm is expected:is expected:

Disconnect antenna Disconnect antenna cables and move them cables and move them away from your radio away from your radio equipment.equipment.

Unplug all power cords Unplug all power cords from the AC outlets.from the AC outlets.

Stop using your radio Stop using your radio equipment and move to equipment and move to another room until the another room until the storm passes.storm passes.

“So Charlie, I guess I’d better think about

signing off, since I just heard a thunder-

clap...”


T0A12 T0A12 (pg 162)(pg 162)

What is the most important reason to have a What is the most important reason to have a lightning protection system for your amateur lightning protection system for your amateur radio station?radio station?A.A. Lower insurance ratesLower insurance rates

B.B. Improved receptionImproved reception

C.C. Fire preventionFire prevention

D.D. Noise reductionNoise reduction


T0A08 T0A08 (pg 163)(pg 163)

What precautions should be taken when a What precautions should be taken when a lightning storm is expected?lightning storm is expected?A.A. Disconnect the antenna cables from your Disconnect the antenna cables from your

station and move them away from your radio station and move them away from your radio equipmentequipment

B.B. Unplug all power cords from AC outletsUnplug all power cords from AC outlets

C.C. Stop using your radio equipment and move to Stop using your radio equipment and move to another room until the storm passesanother room until the storm passes



Antenna & Tower InstallationAntenna & Tower InstallationIf installing a tower/antenna If installing a tower/antenna near an airport you must near an airport you must consider the consider the maximum allowed maximum allowed heightheight with regard to airports. with regard to airports.

An important consideration An important consideration when selecting an antenna location is to make when selecting an antenna location is to make sure people cannot accidentally come into sure people cannot accidentally come into contact with it.contact with it.

The most important safety precaution to observe The most important safety precaution to observe when installing an antenna is to look for and stay when installing an antenna is to look for and stay clear of overhead power linesclear of overhead power lines..


Antenna & Tower Installation (cont.)Antenna & Tower Installation (cont.)

Should your antenna fall, a safe distance Should your antenna fall, a safe distance from power lines is to permit no part of it to from power lines is to permit no part of it to come any closer than 10 feet to a power come any closer than 10 feet to a power line.line.

Towers should be Towers should be grounded with grounded with 8' ground rods 8' ground rods for each tower leg.for each tower leg.


Tower ClimbingTower ClimbingTower climbing is Tower climbing is dangerous!dangerous!Before climbing a tower:Before climbing a tower:

Arrange for a helper / observer.Arrange for a helper / observer.Inspect the tower for damage or Inspect the tower for damage or loose hardware.loose hardware.Verify no nearby electrical storms.Verify no nearby electrical storms.Wear safety belt and use other Wear safety belt and use other safety gear.safety gear.

The ground crew should always The ground crew should always wear a hard hat and safety wear a hard hat and safety glasses in case something glasses in case something accidentally falls from the tower.accidentally falls from the tower.


T0B04 T0B04 (pg 163)(pg 163)

What is an important consideration when What is an important consideration when putting up an antenna?putting up an antenna?A.A. Carefully tune it for a low SWRCarefully tune it for a low SWR

B.B. Make sure people cannot accidentally come Make sure people cannot accidentally come into contact with itinto contact with it

C.C. Make sure you discard all packing Make sure you discard all packing material in a safe placematerial in a safe place

D.D. Make sure birds can see it so they Make sure birds can see it so they don’t fly into itdon’t fly into it


T0B06 T0B06 (pg 163)(pg 163)

What is the most important safety precaution What is the most important safety precaution to observe when putting up an antenna to observe when putting up an antenna tower?tower?A.A. Install steps on the tower for safe climbingInstall steps on the tower for safe climbing

B.B. Insulate the base of the tower to avoid Insulate the base of the tower to avoid lightning strikeslightning strikes

C.C. Ground the base of the tower to prevent Ground the base of the tower to prevent lightning strikeslightning strikes

D.D. Look for and stay clear of any overhead Look for and stay clear of any overhead electrical wireselectrical wires


T0B08 T0B08 (pg 164)(pg 164)

What is a safe distance from a power line to What is a safe distance from a power line to allow when installing an antenna?allow when installing an antenna?A.A. Half the width of your property unless the wires Half the width of your property unless the wires

are at least 23 feet highare at least 23 feet high

B.B. 12.5 feet in most metropolitan areas12.5 feet in most metropolitan areas

C.C. 36 meters plus 1/2 wavelength at the operating 36 meters plus 1/2 wavelength at the operating frequencyfrequency

D.D. So that if the antenna falls unexpectedly, So that if the antenna falls unexpectedly, no part of it can come closer than 10 feet to no part of it can come closer than 10 feet to the power wiresthe power wires


T0B11 T0B11 (pg 164)(pg 164)

What is considered to be an adequate What is considered to be an adequate ground for a tower?ground for a tower?A.A. A single 4 foot ground rod, driven into the A single 4 foot ground rod, driven into the

earth no more than 12 inches from the baseearth no more than 12 inches from the base

B.B. A screen of 120 radial wiresA screen of 120 radial wires

C.C. Separate 8 foot long ground rods for each Separate 8 foot long ground rods for each tower leg, bonded to the tower and each tower leg, bonded to the tower and each otherother

D.D. A connection between the tower base and a A connection between the tower base and a cold water pipecold water pipe


T0B10 T0B10 (pg 164)(pg 164)

Why is stainless steel hardware used on Why is stainless steel hardware used on many antennas instead of other metals?many antennas instead of other metals?A.A. Stainless steel is a better electrical conductorStainless steel is a better electrical conductor

B.B. Stainless steel weighs less than other metalsStainless steel weighs less than other metals

C.C. Stainless steel parts are much less likely to Stainless steel parts are much less likely to corrodecorrode

D.D. Stainless steel costs less than other metalsStainless steel costs less than other metals


T0B07 T0B07 (pg 164)(pg 164)

How should the guy wires for an antenna How should the guy wires for an antenna tower be installed?tower be installed?A.A. So each guy wire anchor point has an even So each guy wire anchor point has an even

number of wiresnumber of wires

B.B. So that no guy wire is more than 25 feet longSo that no guy wire is more than 25 feet long

C.C. Each guy wire must be pulled as tight as Each guy wire must be pulled as tight as possiblepossible

D.D. In accordance with the tower In accordance with the tower manufacturer's instructionsmanufacturer's instructions


T0B01 T0B01 (pg 164)(pg 164)

Why should you wear a hard hat and safety Why should you wear a hard hat and safety glasses if you are on the ground helping glasses if you are on the ground helping someone work on an antenna tower?someone work on an antenna tower?A.A. It is required by FCC rulesIt is required by FCC rules

B.B. To keep RF energy away from your head To keep RF energy away from your head during antenna testingduring antenna testing

C.C. To protect your head and eyes in case To protect your head and eyes in case something accidentally falls from the towersomething accidentally falls from the tower

D.D. It is required by the electrical codeIt is required by the electrical code


T0B03 T0B03 (pg 165)(pg 165)

What should you do before you What should you do before you climb a tower?climb a tower?A.A. Arrange for a helper or observerArrange for a helper or observer

B.B. Inspect the tower for damage or loose Inspect the tower for damage or loose hardwarehardware

C.C. Make sure there are no electrical storms Make sure there are no electrical storms nearbynearby



T0B02 T0B02 (pg 165)(pg 165)

What is a good precaution to observe before What is a good precaution to observe before climbing an antenna tower?climbing an antenna tower?A.A. Turn on all radio transmittersTurn on all radio transmitters

B.B. Remove all tower grounding connectionsRemove all tower grounding connections

C.C. Put on your safety belt and safety glassesPut on your safety belt and safety glasses

D.D. Inform the FAA and the FCC that you are Inform the FAA and the FCC that you are working on a towerworking on a tower


T0B09 T0B09 (pg 165)(pg 165)

What is the most important safety rule to What is the most important safety rule to remember when using a crank-up tower?remember when using a crank-up tower?A.A. This type of tower must never be paintedThis type of tower must never be painted

B.B. Crank up towers must be raised and lowered Crank up towers must be raised and lowered frequently to keep them properly lubricatedfrequently to keep them properly lubricated

C.C. Winch cables must be specially rated for use Winch cables must be specially rated for use on this type of toweron this type of tower

D.D. A crank-up tower should never be climbed A crank-up tower should never be climbed unless it is in the fully lowered positionunless it is in the fully lowered position


RadiationRadiationThere are two types of radiation.There are two types of radiation.Ionizing RadiationIonizing Radiation – individual – individual particles/photons carry enough energy to ionize particles/photons carry enough energy to ionize atoms or molecules by removing electrons.atoms or molecules by removing electrons.

X-raysX-rays

Gamma raysGamma rays

Non-ionizing radiationNon-ionizing radiation - any type of electro- - any type of electro-magnetic radiation that does not carry enough magnetic radiation that does not carry enough energy to ionize atoms or molecules.energy to ionize atoms or molecules.

Radio wavesRadio waves

MicrowavesMicrowaves


Radio Frequency EnergyRadio Frequency EnergyRF burnsRF burns can occur if someone accidentally can occur if someone accidentally touches your antenna while transmitting.touches your antenna while transmitting.

The human body absorbs RF energy at some The human body absorbs RF energy at some frequencies better than others.frequencies better than others.

RF energy can cause injury if the combination of RF energy can cause injury if the combination of power density (signal strength) and frequency power density (signal strength) and frequency cause cause excessive power to be absorbedexcessive power to be absorbed..

Power density is measured in Power density is measured in milliwatts per milliwatts per square centimetersquare centimeter..


RF Safety & Duty CycleRF Safety & Duty CycleDuty cycle is one of the factors used to Duty cycle is one of the factors used to determine safe RF exposure levels.determine safe RF exposure levels.

Duty cycle takes into account the amount Duty cycle takes into account the amount of time a transmitter is operating at full of time a transmitter is operating at full power during a transmission.power during a transmission.

Lower duty cycles expose Lower duty cycles expose people to lower people to lower radio-frequency radiation.radio-frequency radiation.


RF Exposure EvaluationRF Exposure EvaluationYou can determine if your You can determine if your station complies with FCC station complies with FCC RF exposure regulations by:RF exposure regulations by:

Calculation based on FCC Calculation based on FCC OET Bulletin 65.OET Bulletin 65.

Calculation based on computer modeling.Calculation based on computer modeling.

Measurement of field strength using Measurement of field strength using calibrated equipment.calibrated equipment.

If you your station equipment changes, If you your station equipment changes, you will need to re-evaluate.you will need to re-evaluate.


RF Exposure Evaluation (cont.)RF Exposure Evaluation (cont.)Above 30 Mhz you may use a maximum of Above 30 Mhz you may use a maximum of 50 watts PEP at the antenna before an RF 50 watts PEP at the antenna before an RF exposure evaluation is required.exposure evaluation is required.

If you find your RF radiation exceeds the If you find your RF radiation exceeds the FCC limits you may:FCC limits you may:

Alter antenna patterns.Alter antenna patterns.

Relocate antennas.Relocate antennas.

Change frequency or power.Change frequency or power.


T0C02 T0C02 (pg 166)(pg 166)

When can radio waves cause injury to the When can radio waves cause injury to the human body?human body?A.A. Only when the frequency is below 30 MHzOnly when the frequency is below 30 MHz

B.B. Only if the combination of signal strength Only if the combination of signal strength and frequency cause excessive power to be and frequency cause excessive power to be absorbedabsorbed

C.C. Only when the frequency is greater than 30 Only when the frequency is greater than 30 MHzMHz

D.D. Only when transmitter power exceeds 50 wattsOnly when transmitter power exceeds 50 watts


T0C07 T0C07 (pg 167)(pg 167)

What could happen if a person accidentally What could happen if a person accidentally touched your antenna while you were touched your antenna while you were transmitting?transmitting?A.A. Touching the antenna could cause television Touching the antenna could cause television

interferenceinterference

B.B. They might receive a painful RF burn injuryThey might receive a painful RF burn injury

C.C. They would be able to hear what you are They would be able to hear what you are sayingsaying

D.D. NothingNothing


T0C01 T0C01 (pg 167)(pg 167)

What type of radiation are VHF and UHF What type of radiation are VHF and UHF radio signals?radio signals?A.A. Gamma radiationGamma radiation

B.B. Ionizing radiationIonizing radiation

C.C. Alpha radiationAlpha radiation

D.D. Non-ionizing radiationNon-ionizing radiation


T0C04 T0C04 (pg 167)(pg 167)

What factors affect the RF exposure of What factors affect the RF exposure of people near an amateur transmitter?people near an amateur transmitter?A.A. Frequency and power level of the RF fieldFrequency and power level of the RF field

B.B. Distance from the antenna to a personDistance from the antenna to a person

C.C. Radiation pattern of the antennaRadiation pattern of the antenna



T0C03 T0C03 (pg 168)(pg 168)

What is the maximum power level that an What is the maximum power level that an amateur radio station may use at amateur radio station may use at frequencies above 30 MHz before an RF frequencies above 30 MHz before an RF exposure evaluation is required?exposure evaluation is required?A.A. 1500 watts PEP transmitter output1500 watts PEP transmitter output

B.B. 1 watt forward power1 watt forward power

C.C. 50 watts PEP at the antenna50 watts PEP at the antenna

D.D. 50 watts PEP reflected power50 watts PEP reflected power


T0C06 T0C06 (pg 168)(pg 168)

How can you determine that your station How can you determine that your station complies with FCC RF exposure complies with FCC RF exposure regulations?regulations?A.A. By calculation based on FCC OET Bulletin 65By calculation based on FCC OET Bulletin 65

B.B. By calculation based on computer modelingBy calculation based on computer modeling

C.C. By measurement of field strength using By measurement of field strength using calibrated equipmentcalibrated equipment

D.D. All of these choices are correctAll of these choices are correct


T0C11 T0C11 (pg 168)(pg 168)

Why is duty cycle one of the factors used to Why is duty cycle one of the factors used to determine safe RF radiation exposure determine safe RF radiation exposure levels?levels?A.A. It takes into account the amount of time the It takes into account the amount of time the

transmitter is operatingtransmitter is operating

B.B. It takes into account the transmitter power It takes into account the transmitter power supply ratingsupply rating

C.C. It takes into account the antenna feed line lossIt takes into account the antenna feed line loss

D.D. It takes into account the thermal effects of the It takes into account the thermal effects of the final amplifierfinal amplifier


T0C05 T0C05 (pg 169)(pg 169)

Why must the frequency of an RF source be Why must the frequency of an RF source be considered when evaluating RF radiation considered when evaluating RF radiation exposure?exposure?A.A. Lower frequency RF fields have more energy Lower frequency RF fields have more energy

than higher frequency fieldsthan higher frequency fields

B.B. Lower frequency RF fields do not penetrate Lower frequency RF fields do not penetrate the human bodythe human body

C.C. Higher frequency RF fields are transient in Higher frequency RF fields are transient in nature and do not affect the human bodynature and do not affect the human body

D.D. The human body absorbs more RF energy The human body absorbs more RF energy at some frequencies than othersat some frequencies than others


T0C10 T0C10 (pg 169)(pg 169)

Which of the following units of measurement Which of the following units of measurement is used to measure RF radiation exposure?is used to measure RF radiation exposure?A.A. Milliwatts per square centimeterMilliwatts per square centimeter

B.B. Megohms per square meterMegohms per square meter

C.C. Microfarads per footMicrofarads per foot

D.D. Megahertz per secondMegahertz per second


T0C09 T0C09 (pg 169)(pg 169)

How can you make sure your station stays How can you make sure your station stays in compliance with RF safety regulations?in compliance with RF safety regulations?A.A. Compliance is not necessaryCompliance is not necessary

B.B. By re-evaluating the station whenever an By re-evaluating the station whenever an item of equipment is changeditem of equipment is changed

C.C. By making sure your antennas have a low By making sure your antennas have a low SWRSWR

D.D. By installing a low pass filterBy installing a low pass filter


T0C08 T0C08 (pg 170)(pg 170)

What action might amateur operators take to What action might amateur operators take to prevent exposure to RF radiation in excess prevent exposure to RF radiation in excess of FCC supplied limits?of FCC supplied limits?A.A. Alter antenna patternsAlter antenna patterns

B.B. Relocate antennasRelocate antennas

C.C. Change station parameters such as frequency Change station parameters such as frequency or poweror power



Technician License Class Gordon West Technician Class Manual Pages 160-170 Electrical & RF Safety Presented by Heart Of Texas Amateur Radio Club (HOTARC)

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