Safety.
Subel. L09b
44 questions
L09b
Hide Distractors
- L01 33 questions
- L02 60 questions
- L03a 43 questions
- L03b 6 questions
- L04 47 questions
- L05 68 questions
- L06a 11 questions
- L06b 60 questions
- L07 52 questions
- L08 79 questions
- L09a 17 questions
- L09b 44 questions
- L10 54 questions
- L11 87 questions
- L12 32 questions
- L13 55 questions
- L14a 27 questions
- L14b 11 questions
- L15 87 questions
- L16 99 questions
Subelement L09b
Section L09b
How could you best keep unauthorized persons from using your amateur station at home?
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Correct AnswerUse a key-operated on/off switch in the main power line
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Use a carrier-operated relay in the main power line
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Put a "Danger - High Voltage" sign in the station
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Put fuses in the main power line
key word: UNAUTHORIZED. A locked switch in line with the electrical circuit feeding the station would prevent unauthorized operation of the station.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
How could you best keep unauthorized persons from using a mobile amateur station in your car?
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Tune the radio to an unused frequency when you are done using it
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Turn the radio off when you are not using it
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Put a "Do not touch" sign on the radio
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Correct AnswerDisconnect the microphone when you are not using it
Why would you use a key-operated on/off switch in the main power line of your station?
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For safety, in case the main fuses fail
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To keep the power company from turning off your electricity during an emergency
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For safety, to turn off the station in the event of an emergency
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Correct AnswerTo keep unauthorized persons from using your station
key word: UNAUTHORIZED. A locked switch in line with the electrical circuit feeding the station would prevent unauthorized operation of the station.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
Why would there be a switch in a high-voltage power supply to turn off the power if its cabinet is opened?
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To keep dangerous RF radiation from leaking out through an open cabinet
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To keep dangerous RF radiation from coming in through an open cabinet
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To turn the power supply off when it is not being used
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Correct AnswerTo keep anyone opening the cabinet from getting shocked by dangerous high voltages
key words: HIGH-VOLTAGE. Devices operating with high voltage should always include an 'interlock' switch so they power down when cabinets are open to prevent electrocution.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
How little electrical current flowing through the human body can be fatal?
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Approximately 10 amperes
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More than 20 amperes
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Current flow through the human body is never fatal
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Correct AnswerAs little as 20 milliamperes
Which body organ can be fatally affected by a very small amount of electrical current?
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Correct AnswerThe heart
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The brain
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The liver
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The lungs
What is the minimum voltage which is usually dangerous to humans?
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1000 volts
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2000 volts
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Correct Answer30 volts
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100 volts
Under certain circumstances, even 30 VOLTS can be dangerous. If the human heart is part of the electrocution path, even one tenth of an ampere can lead to cardiac arrest. Wet skin or cuts to the skin and the exact path of the current are all factors that determine the severity of electrocution.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
What should you do if you discover someone who is being burned by high voltage?
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Run from the area so you won't be burned too
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Correct AnswerTurn off the power, call for emergency help and provide first-aid if needed
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Wait for a few minutes to see if the person can get away from the high voltage on their own, then try to help
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Immediately drag the person away from the high voltage
What is the safest method to remove an unconscious person from contact with a high voltage source?
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Call an electrician
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Remove the person by pulling an arm or a leg
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Correct AnswerTurn off the high voltage switch before removing the person from contact with the source
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Wrap the person in a blanket and pull him to a safe area
Before checking a fault in a mains operated power supply unit, it would be safest to first:
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remove and check fuse from power supply
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Correct Answerturn off the power and remove power plug
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short out leads of filter capacitor
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check action of capacitor bleeder resistance
key words: "MAINS" OPERATED. This refers to 'Household' current which runs at 120 volts and can supply hundreds of amperes (for a brief time) before a fuse or breaker interrupts the circuit after a fault. 30 VOLTS is considered potentially dangerous to humans and less than A TENTH of an AMPERE can lead to cardiac arrest.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
Fault finding in a power supply of an amateur transmitter while the supply is operating is not a recommended technique because of the risk of:
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overmodulation
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blowing the fuse
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Correct Answerelectric shock
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damaging the transmitter
This was especially true of transmitters using vacuum tubes. Plate voltages ran into the hundreds of volts with current capacities of hundreds of milliamperes. 30 VOLTS is considered potentially dangerous to humans and less than A TENTH of an AMPERE can lead to cardiac arrest.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
For best protection from electrical shock, what should be grounded in an amateur station?
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The antenna transmission line
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The AC power line
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The power supply primary
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Correct AnswerAll station equipment
An external ground connection on each cabinet serves as a backup to the normal electrical outlet ground ( the 'green' wire in a three-lead power cord ).
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
If a separate ground system is not possible for your amateur station, an alternative indoor grounding point could be:
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a metallic natural gas pipe
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Correct Answera metallic cold water pipe
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a plastic cold water pipe
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a window screen
To protect you against electrical shock, the chassis of each piece of your station equipment should be connected to:
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Correct Answera good ground connection
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a dummy load
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insulated shock mounts
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the antenna
An external ground connection on each cabinet serves as a backup to the normal electrical outlet ground ( the 'green' wire in a three-lead power cord ).
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
Which of these materials is best for a ground rod driven into the earth?
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Hard plastic
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Iron or steel
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Fiberglass
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Correct AnswerCopper-clad steel
'Copper-Clad' ( steel core, copper plating ) offers rigidity (when hammering the rod into the ground) and conductivity (for best ground connection).
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
If you ground your station equipment to a ground rod driven into the earth, what is the shortest length the rod should be?
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2.5 metres (8 ft)
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3 metres (10 ft)
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Correct AnswerThe station ground system must conform to applicable electrical code requirements
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1.2 metre (4 ft)
Like everything else about electricity, station and antenna system grounding is governed by the electrical Code applicable to your province. Typically inspired by the "Canadian Electrical Code" (CSA Group, formerly Canadian Standard Association), provincial requirements are often appended to the national code.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
Where should the green wire in a three-wire AC line cord be connected in a power supply?
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To the "hot" side of the power switch
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To the fuse
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Correct AnswerTo the chassis
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To the white wire
The 'green wire' in a three-wire AC line cord is a ground connection. Securing the 'green wire' to the chassis (and outside cabinet) keeps the chassis at ground potential if a fault ever caused the 'live' side (120 volts) of the AC line to contact the chassis.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
If your third-floor amateur station has a ground wire running 10 metres (33 feet) down to a ground rod, why might you get an RF burn if you touch the front panel of your HF transceiver?
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Because of a bad antenna connection, allowing the RF energy to take an easier path out of the transceiver through you
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Because the transceiver's heat-sensing circuit is not working to start the cooling fan
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Because the ground rod is not making good contact with moist earth
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Correct AnswerBecause the ground wire has significant reactance and acts more like an antenna than an RF ground connection
key word: 10 METRES. RF 'hot spots' and RF 'burns' are symptoms of 'Stray RF'. This is relatively long in comparison with some of the wavelengths in the HF (High Frequency) spectrum. For example, 10 metres is a quarter wavelength on the 40 metre band. A wire this long looks like an antenna and will not provide a low impedance ground connection necessary to evacuate 'Stray RF'.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
What is one good way to avoid stray RF energy in your amateur station?
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Make a couple of loops in the ground wire where it connects to your station
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Drive the ground rod at least 4m (14 feet) into the ground
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Use a beryllium ground wire for best conductivity
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Correct AnswerKeep the station's ground wire as short as possible
RF 'hot spots' and RF 'burns' are symptoms of 'Stray RF'. To eliminate 'Stray RF', a low impedance path to ground must be provided. Only SHORT and WIDE ground conductors can provide low impedance.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
Which statement about station grounding is true?
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The chassis of each piece of station equipment should be tied together with high-impedance conductors
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Correct AnswerRF hot spots can occur in a station located above the ground floor if the equipment is grounded by a long ground wire
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A ground loop is an effective way to ground station equipment
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If the chassis of all station equipment is connected with a good conductor, there is no need to tie them to an earth ground
RF 'hot spots' and RF 'burns' are symptoms of 'Stray RF'. To eliminate 'Stray RF', a low impedance path to ground must be provided. Only SHORT and WIDE ground conductors can provide low impedance.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
On mains operated power supplies, the ground wire should be connected to the metal chassis of the power supply. This ensures, in case there is a fault in the power supply, that the chassis:
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does not become conductive to prevent electric shock
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becomes conductive to prevent electric shock
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develops a high voltage compared to the ground
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Correct Answerdoes not develop a high voltage with respect to the ground
The 'green wire' in a three-wire AC line cord is a ground connection. Securing the 'green wire' to the chassis (and outside cabinet) keeps the chassis at ground potential if a fault ever caused the 'live' side (120 volts) of the AC line to contact the chassis.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
The purpose of using a three-wire power cord and plug on amateur radio equipment is to:
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prevent internal short circuits
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make it inconvenient to use
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Correct Answerprevent the chassis from becoming live
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prevent the plug from being reversed in the wall outlet
The 'green wire' in a three-wire AC line cord is a ground connection. Securing the 'green wire' to the chassis (and outside cabinet) keeps the chassis at ground potential if a fault ever caused the 'live' side (120 volts) of the AC line to contact the chassis.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
Why should you ground all antenna and rotator cables when your amateur station is not in use?
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To avoid radio frequency interference
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To make sure everything will stay in place
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Correct AnswerTo help protect the station equipment and building from lightning damage
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To lock the antenna system in one position
You want to install a lightning arrestor on your antenna transmission line, where should it be inserted?
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Correct AnswerOutside, as close to earth grounding as possible
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Close to the antenna
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Behind the transceiver
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Anywhere on the line
The lightning arrestor must be outside to prevent as much energy as possible from entering the premises. It must be close to ground so that a path with the least possible impedance (resistance + inductance) can divert the most energy into the ground. Peak voltage between the transmission line and ground is thus minimized. Rise time in a lightning bolt is measured in microseconds (i.e., high frequency); voltage is high and current is zero in the first instant an inductance is subjected to a pulse.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
How can amateur station equipment best be protected from lightning damage?
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Use heavy insulation on the wiring
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Never turn off the equipment
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Disconnect the ground system from all radios
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Correct AnswerDisconnect all equipment from the power lines and antenna cables
If station equipment is totally disconnected from external circuits (power and antenna), damage to station equipment from lightning or voltage surges become impossible.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
What equipment should be worn for working on an antenna tower?
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Correct AnswerApproved equipment in accordance with applicable standards concerning fall protection
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A reflective vest of approved colour
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A flashing red, yellow or white light
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A grounding chain
Why should you wear approved fall arrest equipment if you are working on an antenna tower?
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To keep the tower from becoming unbalanced while you are working
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To safely hold your tools so they don't fall and injure someone on the ground
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Correct AnswerTo prevent you from accidentally falling
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To safely bring any tools you might use up and down the tower
'Fall prevention' is a serious matter. In Canada, worker safety is a provincial responsibility. A 'safety harness' and 'hard hat' are minimum requirements.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
For safety, how high should you place a horizontal wire antenna?
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Above high-voltage electrical lines
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Just high enough so you can easily reach it for adjustments or repairs
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As close to the ground as possible
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Correct AnswerHigh enough so that no one can touch any part of it from the ground
Even at modest power, touching a radiating antenna or open-wire line can lead to 'RF burns'. Voltage is not the only factor, radio frequency reaches deep into the skin, potentially causing nasty burns. Suspending an antenna above electric lines is a dangerous mistake: if the antenna dropped, lethal voltages would be carried back to the station.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
Why should you wear a hard hat if you are on the ground helping someone work on an antenna tower?
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To keep RF energy away from your head during antenna testing
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So someone passing by will know that work is being done on the tower and will stay away
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Correct AnswerTo protect your head from something dropped from the tower
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So you won't be hurt if the tower should accidentally fall
Why should your outside antennas be high enough so that no one can touch them while you are transmitting?
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Touching the antenna might radiate harmonics
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Touching the antenna might cause television interference
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Correct AnswerTouching the antenna might cause RF burns
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Touching the antenna might reflect the signal back to the transmitter and cause damage
Even at modest power, touching a radiating antenna or open-wire line can lead to 'RF burns'. Voltage is not the only factor, radio frequency reaches deep into the skin, potentially causing nasty burns.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
Why should you make sure that no one can touch an open wire transmission line while you are transmitting with it?
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Correct AnswerBecause high-voltage radio energy might burn the person
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Because contact might break the transmission line
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Because contact might cause spurious emissions
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Because contact might cause a short circuit and damage the transmitter
Even at modest power, touching a radiating antenna or open-wire line can lead to 'RF burns'. Voltage is not the only factor, radio frequency reaches deep into the skin, potentially causing nasty burns.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
What safety precautions should you take before beginning repairs on an antenna?
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Be sure you and the antenna structure are grounded
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Inform your neighbours so they are aware of your intentions
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Turn off the main power switch in your house
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Correct AnswerBe sure to turn off the transmitter and disconnect the transmission line
"Disconnecting the transmission line", that is an important precaution to ensure that no RF is ever sent to the antenna. This is especially important if there are several parties in the work crew: an operator could return to the station, turn-on a transmitter and put someone outside at risk.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
What precaution should you take when installing a ground-mounted antenna?
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It should not be installed in a wet area
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It should not be installed higher than you can reach
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Correct AnswerIt should be installed so no one can come in contact with it
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It should be painted so people or animals do not accidentally run into it
Even at modest power, touching a radiating antenna or open-wire line can lead to 'RF burns'. Voltage is not the only factor, radio frequency reaches deep into the skin, potentially causing nasty burns.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
What should you do for safety when operating at UHF and microwave frequencies?
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Correct AnswerKeep antenna away from your eyes when RF is applied
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Make sure that an RF leakage filter is installed at the antenna feed point
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Make sure the standing wave ratio is low before you conduct a test
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Never use a horizontally polarized antenna
RF energy can heat body tissue. 1000 MHz is generally considered to be the low end of the MICROWAVE spectrum. Microwave energy has long been known for its 'heating' effect ( think "microwave oven" ). Never point antennas at anyone. Never look into antennas. Disconnect transmission lines before working on antennas (to further reduce the odds of an error at the station exposing to RF).
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
What should you do for safety if you put up a UHF transmitting antenna?
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Make sure that RF field screens are in place
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Correct AnswerMake sure the antenna will be in a place where no one can get near it when you are transmitting
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Make sure the antenna is near the ground to keep its RF energy pointing in the correct direction
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Make sure you connect an RF leakage filter at the antenna feed point
RF energy can heat body tissue. VHF and UHF frequencies present the greatest risk. Never point antennas at anyone. Never look into antennas. Disconnect transmission lines before working on antennas (to further reduce the odds of an error at the station exposing to RF).
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
What should you do for safety, before removing the shielding on a UHF power amplifier?
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Correct AnswerMake sure the amplifier cannot accidentally be turned on
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Make sure that RF leakage filters are connected
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Make sure the antenna transmission line is properly grounded
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Make sure all RF screens are in place at the antenna transmission line
Why should you make sure the antenna of a hand-held transceiver is not close to your head when transmitting?
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To help the antenna radiate energy equally in all directions
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Correct AnswerTo reduce your exposure to the radio-frequency energy
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To use your body to reflect the signal in one direction
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To keep static charges from building up
RF energy can heat body tissue. VHF and UHF frequencies present the greatest risk. 30 MHz to 300 MHz is the range of radio frequencies over which Health-Canada's "Safety Code 6" recommends the lowest exposure level.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
How should you position the antenna of a hand-held transceiver while you are transmitting?
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Pointed towards the station you are contacting
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Pointed away from the station you are contacting
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Pointed down to bounce the signal off the ground
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Correct AnswerAway from your head and away from others
RF energy can heat body tissue. VHF and UHF frequencies present the greatest risk. 30 MHz to 300 MHz is the range of radio frequencies over which Health-Canada's "Safety Code 6" recommends the lowest exposure level.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
How can exposure to a large amount of RF energy affect body tissue?
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It paralyzes the tissue
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It causes hair to fall out
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Correct AnswerIt heats the tissue
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It lowers blood pressure
RF energy can heat body tissue. VHF and UHF frequencies present the greatest risk. 30 MHz to 300 MHz is the range of radio frequencies over which Health-Canada's "Safety Code 6" recommends the lowest exposure level.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
Which body organ is the most likely to be damaged from the heating effects of RF radiation?
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Correct AnswerEyes
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Heart
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Liver
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Hands
The inside of the eye is mostly liquid. Ever seen a cup of water brought to a boil in a microwave oven ? RF energy can heat body tissue. VHF and UHF frequencies present the greatest risk. 30 MHz to 300 MHz is the range of radio frequencies over which Health-Canada's "Safety Code 6" recommends the lowest exposure level. Keep antennas away from your head.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
Depending on the wavelength of the signal, the energy density of the RF field, and other factors, in what way can RF energy affect body tissue?
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It causes blood flow to stop
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It has no effect on the body
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Correct AnswerIt heats the tissue
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It causes ionizing radiation poisoning
RF energy can heat body tissue. VHF and UHF frequencies present the greatest risk. 30 MHz to 300 MHz is the range of radio frequencies over which Health-Canada's "Safety Code 6" recommends the lowest exposure level.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
If you operate your amateur station with indoor antennas, what precautions should you take when you install them?
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Correct AnswerLocate the antennas as far away as possible from living spaces that will be occupied while you are operating
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Position the antennas parallel to electrical power wires to take advantage of parasitic effects
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Position the antennas along the edge of a wall where it meets the floor or ceiling to reduce parasitic radiation
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Locate the antennas close to your operating position to minimize transmission line length
Why should directional high-gain antennas be mounted higher than nearby structures?
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Correct AnswerSo they will not direct RF energy toward people in nearby structures
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So they will be dried by the wind after a heavy rain storm
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So they will not damage nearby structures with RF energy
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So they will receive more sky waves and fewer ground waves
RF energy can heat body tissue. VHF and UHF frequencies present the greatest risk. Never point antennas at anyone. Never look into antennas. Disconnect transmission lines before working on antennas (to further reduce the odds of an error at the station exposing to RF).
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
For best RF safety, where should the ends and center of a dipole antenna be located?
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As close to the transmitter as possible so RF energy will be concentrated near the transmitter
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Close to the ground so simple adjustments can be easily made without climbing a ladder
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Correct AnswerAs high as possible to prevent people from coming in contact with the antenna
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Near or over moist ground so RF energy will be radiated away from the ground
Even at modest power, touching a radiating antenna or open-wire line can lead to 'RF burns'. Voltage is not the only factor, radio frequency reaches deep into the skin, potentially causing nasty burns.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
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