Technician Class Series – Safety First!


Hello everybody and welcome back to Everything Hamradio! Today we are going to talk about the last section in our Technician Class License Question Pool! Today we will be talking about Safety.

As always, the correct answers will be in bold. I also recommend that you only read the correct answers when studying for your test. If you do this, when you take your test and you see a question, there will be a better chance that the correct answer will jump out at you easier. Some say that this approach is kind of like cheating, but the way that I see it, you will always be learning something in this hobby and you don’t have to know everything there is to know about the hobby to get your license.

If you would like to purchase a copy of the Technician Class study book, written by Gordon West, WB6NOA with Eric P. Nichols, KL7AJ, that this series is loosely based around, below is a link to it.

Let’s move on to the good stuff, shall we?

T0A06 What is a good way to guard against electrical shock at your station?

  1. Use three-wire cords and plugs for all AC powered equipment
  2. Connect all AC powered station equipment to a common safety ground
  3. Use a circuit protected by a ground-fault interrupter
  4. All of these choices are correct

All of these choices are correct! The third prong on your electrical plugs is a grounding plug. This ensures that whatever you are plugging in has some kind of ground. Talking about having a ground, having a common one should be high on your priority list. You could get audio interference by have two pieces of equipment that you are using together plugged into two separate grounds. This isn’t as big of a deal with amateur radio since most of the time your equipment is going to be all in the same room, so it will probably be all the same ground, but in things like Audio systems, if you have your mixer board and speakers plugged into different grounds, you could get a 60 Hz hum out of your speakers. With any piece of amateur radio equipment, you want to protect it as much as possible right? After all, amateur radio equipment is typically not cheap! You should always connect your equipment with some type of ground-fault interrupter, whether it is a circuit break or more typically a fuse.

T0A03 What is connected to the green wire in a three-wire electrical AC plug?

  1. Neutral
  2. Hot
  3. Safety ground
  4. The white wire

The center pin on a plug should be connected to the chassis or safety ground of your equipment.

T0A08 What safety equipment should always be included in home-built equipment that is powered from 120V AC power circuits?

  1. A fuse or circuit breaker in series with the AC hot conductor
  2. An AC voltmeter across the incoming power source
  3. An inductor in series with the AC power source
  4. A capacitor across the AC power source

Whether you are talking about an old piece of equipment or a brand new one, you should ALWAYS put a fuse or circuit breaker in series with the AC hot conductor.

T0A04 What is the purpose of a fuse in an electrical circuit?

  1. To prevent power supply ripple from damaging a circuit
  2. To interrupt power in case of overload
  3. To limit current to prevent shocks
  4. All of these choices are correct

The purpose of a fuse or circuit breaker in any electrical circuit is to interrupt power in case of overload. You wouldn’t want your brand new $3000 radio to become a “boat anchor” because of a power spike that you didn’t have proper protection do you? I know, I don’t! I have fuses on all my radios whether they cost me $15 or $3000 and I not only have a fuse on the hot lead but also on the negative lead.

T0A05 Why is it unwise to install a 20-ampere fuse in the place of a 5-ampere fuse?

  1. The larger fuse would be likely to blow because it is rated for higher current
  2. The power supply ripple would greatly increase
  3. Excessive current could cause a fire
  4. All of these choices are correct

Let’s look at this question in a more common situation. Think of a circuit as a pizza or casserole and the power cord, the current to be more specific, as the oven. If the directions on the frozen pizza box says to cook the pizza at 350 degrees for 12 minutes, what do you think would happen if you instead cooked your pizza at 1400(4x 350 degrees) degrees for 12 minutes? More than likely your pizza would burst into flames, catch the oven on fire and possibly even your house. The same thing can happen with your electrical equipment, whether we are talking about amateur radio equipment or something else. Power, especially overloaded power, creates heat, when you overload a circuit it creates more heat than it is designed to dissipate and can catch fire.

T0A11 What kind of hazard might exist in a power supply when it is turned off and disconnected?

  1. Static electricity could damage the grounding system
  2. Circulating currents inside the transformer might cause damage
  3. The fuse might blow if you remove the cover
  4. You might receive an electric shock from the charged stored in large capacitors

Capacitors are designed to store electrical energy. Unless there is some way for the electrical energy to be dissipated, a capacitor can store the energy for a long time. A perfect example of this is the power cord for your laptop. There is a small power light on the power pack that shows that it is plugged in and sending power to your laptop. Unplug the power cord from the wall and watch the light. I doesn’t immediately go out but fades over a few seconds. Now, plug it back in and unplug your laptop. Now unplug the cord from the wall and watch the light again. The light will stay on longer, because there isn’t as much need for the power that it is producing so it takes longer for the light to go out. Inside the power cord, or more specifically the transformer box, there are several capacitors that are used to level out the ,AC to DC power conversion circuits.

T7D12 Which of the following precautions should be taken when measuring high voltages with a voltmeter?

  1. Ensure that the voltmeter has very low impedance
  2. Ensure that the voltmeter and leads are rated for use at the voltages to be measured
  3. Ensure that the circuit is grounded through the voltmeter
  4. Ensure that the voltmeter is set to the correct frequency

The first thing that you should do is to ensure that the voltmeter and leads are rated for use at the voltages to be measured. Even if your use the appropriate meter and leads, your should be even more aware of what you are doing while you are testing something with high voltage. You should try to use just one hand to test with to give one less route for the electricity to flow. The best way to test high voltage is to turn the power off to the circuit, drain any residual charge from any circuits, connect the leads to where you want to test at then step back and turn the power back on. This way you are not even touching the circuit while you are trying to test it.

T0A02 How does current flowing through the body cause a health hazard?

  1. By heating tissue
  2. It disrupts the electrical functions of cells
  3. It causes involuntary muscle contractions
  4. All of these choices are correct

All of these choices are correct. Even though what you generally hear about when you hear about or see someone getting shocked and all you really hear/see is the large spark and then “So and so got shocked and is hurt”, there is a lot more that happens when you get shocked. The tissue in your body will heat up when current is applied to it because your body is trying to dissipate the charge so it converts energy to heat. Secondly, the cells in your body and especially your brain, work by small electrical charges, so an electrical shock can throw those cells into confusion and the may not work properly or die afterwards. Something else that normally happens is muscle contractions. Often times you hear how someone touched a wire and couldn’t let go. This is because the muscles in their hand have contracted because of the electrical shock and even though your brain is telling your hand to let go, the muscles can’t respond.

T2C02 What is one way to recharge a 12-volt lead-acid station battery if the commercial power is out?

  1. Cool the battery in ice for several hours
  2. Add acid to the battery
  3. Connect the battery in parallel with a vehicle’s battery and run the engine
  4. All of these choices are correct

I’m sure that, if you drive, you have had a dead battery on your car at one point in time. What do you have to do to get your car started again? You need a jump right? What are you doing when you jump a car off from someone else’s vehicle? You are connecting your battery in parallel with their battery in order to charge yours up enough to get your car started. Since voltage splits in a parallel circuit, the voltage that their alternator is producing, is being split between their battery and your battery through your jumper cables. Once your battery has enough of a charge to start your engine, your all good. This can also be done with other batteries as well. Things like your HT’s batteries or a go pack battery. If you hook the batteries in parallel with your car battery and start your engine it will charge those batteries from your car’s electrical system. Just make sure that you are using the proper connections to charge whatever battery you are “jumping” so that you do not get shocked.

T0A10 What can happen if a lead-acid storage battery is charged or discharged too quickly?

  1. The battery could overheat and give off flammable gas or explode
  2. The voltage can become reversed
  3. The memory effect will reduce the capacity of the battery
  4. All of these choices are correct

If you charge or discharge a battery to fast by supplying it with too much current or voltage, it could overheat and possible explode. I’m sure that you have noticed that sometimes a freshly charged battery is warm to the touch, or maybe when you are talking on your cell phone a lot, how your battery can get warm. This is happening because your battery is charging or discharging. You should always use the provided charging cord with your hand-held batteries whether it is a cell phone or a HT.

T0A01 Which of the following is a safety hazard of a 12-volt storage battery?

  1. Touching both terminals with the hands can cause electrical shock
  2. Shorting the terminals can cause burns, fire, or an explosion
  3. RF emissions from the battery
  4. All of these choices are correct

While it is possible that you might get shocked by touching both terminals of a 12 volt battery, it is not very likely that you will be able to feel it because of the low voltage of the battery. However, if you put something across the terminals that is highly conductive, say like a wrench or something, you might cause burns, fire or an explosion.

T0A09 What kind of hazard is presented by a conventional 12-volt storage battery?

  1. It emits ozone which can be harmful to the atmosphere
  2. Shock hazard due to high voltage
  3. Explosive gas can collect if not properly vented
  4. All of these choices are correct

If you place a conventional 12 volt battery in a sealed or not properly vented storage container, there could be a build up of hazardous and explosive gases inside that container. You should always make sure that your batteries have proper ventilation to keep this from happening.

T0B04 Which of the following is an important safety precaution to observe when putting up an antenna tower?

  1. Wear a ground strap connected to your wrist at all times
  2. Insulate the base of the tower to avoid lightning strikes
  3. Look for and stay clear of any overhead electrical wires
  4. All of these choices are correct

One of the things you should always do when working off of terra firma is to always check for and watch out for overhead electrical wires. If you or your tower comes in contact with an overhead wire, it will give the current a short and direct path to ground and shock anyone or anything touching the tower.

T0B06 What is the minimum safe distance from a power line to allow when installing an antenna?

  1. Half the width of your property
  2. The height of the power line above ground
  3. 1/2 wavelength at the operating frequency
  4. So that if the antenna falls unexpectedly, no part of it can come closer than 10 feet to the power wires

The minimum safe distance that you want to install your tower is to consider that if somehow you tower falls straight over that not part of the tower or the antennas on top of it with come within 10 feet of the power lines.

T0B09 Why should you avoid attaching an antenna to a utility pole?

  1. The antenna will not work properly because of induced voltages
  2. The utility company will charge you an extra monthly fee
  3. The antenna could contact high-voltage power wires
  4. All of these choices are correct

While it might seem like a half way good idea to do whatever you can to get your antenna as high as possible, especially just starting out and not having a tower or pole to install an antenna on. It is just not a good idea to mount an antenna to a utility pole because the antenna could contact high-voltage power wires.

T0B02 What is a good precaution to observe before climbing an antenna tower?

  1. Make sure that you wear a grounded wrist strap
  2. Remove all tower grounding connections
  3. Put on a climbing harness and safety glasses
  4. All of the these choices are correct

You have a 20 foot tower and you come home one day and notice that something is wrong with your antenna. You could just walk over and start climbing up the tower, fix what is wrong and climb back down. You could do all that without anything happening, but what if it doesn’t go that smoothly? What if you miss a rung and slip and fall? What if while you are working on whatever is wrong at the top that your hand cramps up and you lose your grip? Even though it is only a 20 foot tower, you could still get severely hurt or even killed by just a 20 fall. You should ALWAYS put on a climbing harness and safety glass before climbing a tower so that you minimize your risk of something happening while you feet on not firmly planted on the ground.

T0B03 Under what circumstances is it safe to climb a tower without a helper or observer?

  1. When no electrical work is being performed
  2. When no mechanical work is being performed
  3. When the work being done is not more than 20 feet above the ground
  4. Never

Even if you are wearing your climbing harness and safety glasses and you just have a quick fix to make to something on your tower. What happens if the worst case scenario happens and you pass out or get stuck and there is no one around and your don’t have a phone? How long could you be stuck up on top of that tower before someone comes looking for you? You should always have someone there with you when you climb your tower to make sure that nothing happens or at the very least can call for help if you get in trouble. NEVER, ever climb alone.

T0B01 When should members of a tower work team wear a hard hat and safety glasses?

  1. At all times except when climbing the tower
  2. At all times except when belted firmly to the tower
  3. At all times when any work is being done on the tower
  4. Only when the tower exceeds 30 feet in height

Anytime someone is working on the tower, a hard hat should be worn. If something were to fall from above and hit you in the head, no matter the size of the object, if it was dropped from high enough it could severely hurt you.

T0B05 What is the purpose of a gin pole?

  1. To temporarily replace guy wires
  2. To be used in place of a safety harness
  3. To lift tower sections or antennas
  4. To provide a temporary ground

A gin pole is used to lift tower sections or antennas into place. It is a pole, normally with a pulley on one end. You attach it to the top of your tower and raise it above the top enough to raise the next section of your tower up to you or to mount the antenna on top.

T0B07 Which of the following is an important safety rule to remember when using a crank-up tower?

  1. This type of tower must never be painted
  2. This type of tower must never be grounded
  3. This type of tower must never be climbed unless it is in the fully retracted position
  4. All of these choices are correct

Anytime you have a crank up tower, the only time that it should be climbed is when it is fully retracted. The tower is not made to support anything more than antennas when it is fully erected. It more than likely will not have guy wires to help support it either, making it really dangerous to climb is not fully retracted.

T0B11 Which of the following establishes grounding requirements for an amateur radio tower or antenna?

  1. FCC Part 97 Rules
  2. Local electrical codes
  3. FAA tower lighting regulations
  4. Underwriters Laboratories’ recommended practices

Always check with your local electrical codes before erecting a tower on your property.

T0B08 What is considered to be a proper grounding method for a tower?

  1. A single four-foot ground rod, driven into the ground no more than 12 inches from the base
  2. A ferrite-core RF choke connected between the tower and ground
  3. Separate eight-foot long ground rods for each tower leg, bonded to the tower and each other
  4. A connection between the tower base and a cold water pipe

To properly ground a tower, you should put down separate 8′ ground rounds, typically 3, beside each leg, then bound them bother to the corresponding leg and also to each other.

T4A08 Which type of conductor is best to use for RF grounding?

  1. Round stranded wire
  2. Round copper-clad steel wire
  3. Twisted-pair cable
  4. Flat strap

The best type of conductor to use for RF grounding is a Flat strap. A flat strap is typically made of copper and generally comes in 3″ widths. A flat strap offers the best surface area to bleed off static and to minimize ground currents that could cause interference.

T0B12 Which of the following is good practice when installing ground wires on a tower for lightning protection?

  1. Put a loop in the ground connection to prevent water damage to the ground system
  2. Make sure that all bends in the ground wires are clean, right angle bends
  3. Ensure that connections are short and direct
  4. All of these choices are correct

You should always use the shortest and most direct path from your tower to ground.

T0B10 Which of the following is true concerning grounding conductors used for lightning protection?

  1. Only non-insulated wire must be used
  2. Wires must be carefully routed with precise right-angle bends
  3. Sharp bends must be avoided
  4. Common grounds must be avoided

When grounding you should avoid using sharp bends. An electrical current will generally go on the path of least resistance. A sharp turn is major resistance, when it comes to like a lightning strike. Typically what the charge will do is jump from the ground strap to whatever is in line with the direction before the turn.

T0A07 Which of these precautions should be taken when installing devices for lightning protection in a coaxial cable feed line?

  1. Include a parallel bypass switch for each protector so that it can be switched out of the circuit when running high power
  2. Include a series switch in the ground line of each protector to prevent RF overload from inadvertently damaging the protector
  3. Keep the ground wires from each protector separate and connected to station ground
  4. Ground all of the protectors to a common plate which is in turn connected to an external ground

You should always ground all your equipment to the same ground, like we spoke about earlier in this post. So you should ground all your protectors to a common plate and then ground that plate to an external ground.

T0C04 What factors affect the RF exposure of people near an amateur station antenna?

  1. Frequency and power level of the RF field
  2. Distance from the antenna to a person
  3. Radiation pattern of the antenna
  4. All of these choices are correct

All of the choices are correct. Different frequencies and power level will affect how much radiation there is sent from the antenna. The radiation pattern of an antenna also plays a part on exposure because there is more radiation to the front of a beam than the back of it. The distance from the antenna to the person also is a factor because the farther away from the antenna you are the weaker the radiation is.

T0C05 Why do exposure limits vary with frequency?

  1. Lower frequency RF fields have more energy than higher frequency fields
  2. Lower frequency RF fields do not penetrate the human body
  3. Higher frequency RF fields are transient in nature
  4. The human body absorbs more RF energy at some frequencies than at others

The human body absorbs different amounts of RF energy at different frequencies. Somewhere around the 6 meter band is where the human body absorbs the most amount of radiation.

T0C02 Which of the following frequencies has the lowest value for Maximum Permissible Exposure limit?

  1. 3.5 MHz
  2. 50 MHz
  3. 440 MHz
  4. 1296 MHz

The 6 meter band, around 50 MHz, has the most effect on the human body therefore requires greater distances from the antenna to any person. You should never use an antenna that is closer than 5 feet from your or anyone else. When talking on 6 meters, as long as your antenna is more than 20 feet away and you are using a modest power level, you should be good.

T0C03 What is the maximum power level that an amateur radio station may use at VHF frequencies before an RF exposure evaluation is required?

  1. 1500 watts PEP transmitter output
  2. 1 watt forward power
  3. 50 watts PEP at the antenna
  4. 50 watts PEP reflected power

At 50 watts PEP at the antenna or more, you must do a RF Exposure evaluation to make sure that you are not exposing anyone to dangerous RF radiation.

T0C01 What type of radiation are VHF and UHF radio signals?

  1. Gamma radiation
  2. Ionizing radiation
  3. Alpha radiation
  4. Non-ionizing radiation

The transmission of radio frequency energy from your antenna is considered Non-ionizing radiation.

T0C06 Which of the following is an acceptable method to determine that your station complies with FCC RF exposure regulations?

  1. By calculation based on FCC OET Bulletin 65
  2. By calculation based on computer modeling
  3. By measurement of field strength using calibrated equipment
  4. All of these choices are correct

To determine if you are in compliance with the FCC RF exposure regulations you can use any or all of the choices. 

T0C08 Which of the following actions might amateur operators take to prevent exposure to RF radiation in excess of FCC-supplied limits?

  1. Relocate antennas
  2. Relocate the transmitter
  3. Increase the duty cycle
  4. All of these choices are correct

Of these choices, the only one that will affect the exposure of RF radiation is to relocate your antenna.

T0C09 How can you make sure your station stays in compliance with RF safety regulations?

  1. By informing the FCC of any changes made in your station
  2. By re-evaluating the station whenever an item of equipment is changed
  3. By making sure your antennas have low SWR
  4. All of these choices are correct

Whenever you add something to your station, you should re-evaluate your station to make sure that you are still within compliance with RF safety regulations.

T0C11 What is the definition of duty cycle during the averaging time for RF exposure?

  1. The difference between the lowest power output and the highest power output of a transmitter
  2. The difference between the PEP and average power output of a transmitter
  3. The percentage of time that a transmitter is transmitting
  4. The percentage of time that a transmitter is not transmitting

The duty cycle of anything is the percentage of time that whatever it is, is being used. So in the example of a radio, the duty cycle is the percentage of time that a transmitter is transmitting.

T0C12 How does RF radiation differ from ionizing radiation (radioactivity)?

  1. RF radiation does not have sufficient energy to cause genetic damage
  2. RF radiation can only be detected with an RF dosimeter
  3. RF radiation is limited in range to a few feet
  4. RF radiation is perfectly safe

In layman’s terms, the definition of ionizing radiation is something that ionizes things. A radiation that causes a chemical reaction to something. Thinks like ultraviolet radiation can cause damage at the cellular level, but since as amateur radio operators we don’t transmit in the ultra violet part of the spectrum, your chances of causing any ionizing radiation is basically null.

T0C13 If the averaging time for exposure is 6 minutes, how much power density is permitted if the signal is present for 3 minutes and absent for 3 minutes rather than being present for the entire 6 minutes?

  1. 3 times as much
  2. 1/2 as much
  3. 2 times as much
  4. There is no adjustment allowed for shorter exposure times

If the pattern continues, 3 on and 3 off, it would take two times the exposure to be out of compliance.

T0C10 Why is duty cycle one of the factors used to determine safe RF radiation exposure levels?

  1. It affects the average exposure of people to radiation
  2. It affects the peak exposure of people to radiation
  3. It takes into account the antenna feed line loss
  4. It takes into account the thermal effects of the final amplifier

The duty cycle is part of the average exposure equation. If you have half duty cycle it will take twice as much exposure to be out of compliance. If your duty cycle is less than that, then it takes more.

T0C07 What could happen if a person accidentally touched your antenna while you were transmitting?

  1. Touching the antenna could cause television interference
  2. They might receive a painful RF burn
  3. They might develop radiation poisoning
  4. All of these choices are correct

If your power output is high enough and someone accidentally or intentionally touches your antenna while you are transmitting, it could actually burn them. You always want to make sure that no one can touch your antenna while transmitting.

So that brings us to the end of this section. Next week we will wrap this series up with some helpful information about finding a place to take your test, places to buys equipment and more. Please share my blog with your friends and if you have not done so already, please subscribe to my email list to get  Please Like me on Facebook, and follow me on Twitter, Google+, LinkedIn and StumbledUpon. Links to all of these can be found under social on the menu.

Thanks for stopping by. If you have any questions or comments about today’s post, please leave them in the comments below or shoot me an email a

Until next time…

73 de Curtis, K5CLM

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