Technician Licensing Class “T0”

1. Technician Licensing Class“T0” Presented by the Plano Texas Stake Plano, Texas February 3, 2007

2. Amateur Radio Technician ClassElement 2 • ELEMENT 2 SUBELEMENTS • T1 - FCC Rules, station license responsibilities • T2 - Control operator duties • T3 - Operating practices • T4 - Radio and electronic fundamentals • T5 - Station setup and operation • T6 - Communications modes and methods • T7 - Special operations • T8 - Emergency and Public Service Communications • T9 - Radio waves, propagation, and antennas • T0 - Electrical and RF Safety

3. Electrical and RF Safety T0A • AC power circuits, Electrical code compliance • A few good ways to guard against electrical shock at your station are: • Use 3-wire cords and plugs for all AC powered equipment • Use a ground-fault interrupter at each electrical outlet • Connect all AC powered station equipment to a common ground All of these answers are correct • The most important thing to consider when installing an emergency disconnect switch at your station is for everyone to know where it is and how to use it.

4. Three Wire Plug • In a three wire AC electrical line: Black is HOT White is NEUTRAL Green is Chassis Ground Breaker box Service Disconnect on left.

5. Ground Everything For best protection from electrical shock all equipment should be connected to a common ground.

6. Electrical and RF Safety T0A • Hazardous voltages • The commonly accepted value for the lowest voltage that can cause a dangerous electric shock is 30 volts. (Note: Lower voltages can be just as dangerous where conditions result in lower levels of resistance and thus current levels approaching 100 miliamperes.) • The lowest amount of electrical current flowing through the human body that is likely to cause death is 100 milliamperes. • A hazard might still exist in a power supply when it is turned off and disconnected. If you aren’t careful you might receive an electric shock from stored charge in large capacitors.

8. Electrical and RF Safety T0A • Fuses and circuit breakers • The purpose of a fuse in an electrical circuit is to interrupt power in case of overload. • If you install a 20-ampere fuse in your transceiver in the place of a 5-ampere fuse excessive current could cause a fire. (Note: If it didn’t cause a fire, it still could result in damage to the equipment.) • Grounding • Ground is connected to the green wire in a three-wire electrical plug.

9. Electrical and RF Safety T0A • Lightning protection • The precautions that should be taken when a lightning storm is expected are: • Disconnect the antenna cables from your station and move them away from your radio equipment • Unplug all power cords from AC outlets • Stop using your radio equipment and move to another room until the storm passes All of these answers are correct • Fire prevention is the most important reason to have a lightning protection system for your amateur radio station.

10. Electrical and RF Safety T0A • Battery safety • One way to recharge a 12-volt battery if the commercial power is out is to connect the battery to a car's battery and run the engine. • If a storage battery is charged or discharged too quickly it could overheat and give off dangerous gas or explode. • The hazards that are presented by a conventional 12-volt storage battery are: • It contains dangerous acid that can spill and cause injury • Short circuits can damage wiring and possibly cause a fire • Explosive gas can collect if not properly vented All of these answers are correct

11. Electrical and RF Safety T0B • Antenna installation • An important consideration when putting up an antenna is make sure people cannot accidentally come into contact with it. • The maximum allowed height with regard to nearby airports must be considered when erecting an antenna near an airport. • Tower safety • You should wear a hard hat and safety glasses if you are on the ground helping someone work on an antenna tower in order to protect your head and eyes in case something accidentally falls from the tower. • A good precaution to observe before climbing an antenna tower is to put on your safety belt and safety glasses.

12. Electrical and RF Safety T0B • Tower safety (cont) • You should do all of the following before you climb a tower: • Arrange for a helper or observer • Inspect the tower for damage or loose hardware • Make sure there are no electrical storms nearby All of these answers are correct • Guy wires for an antenna tower should be installed in accordance with the tower manufacturer's instructions.

13. Electrical and RF Safety T0B • Tower safety (cont) • The most important safety rule to remember when using a crank-up tower is a crank-up tower should never be climbed unless it is in the fully lowered position. • Stainless steel hardware is used on many antennas instead of other metals because stainless steel parts are much less likely to corrode. • A separate 8 foot long ground rods for each tower leg, bonded to the tower and each other is considered to be an adequate ground for a tower.

14. Electrical and RF Safety T0B • Overhead power lines • The most important safety precaution to observe when putting up an antenna tower is look for and stay clear of any overhead electrical wires. • A safe distance from a power line to allow when installing an antenna is so that if the antenna falls unexpectedly, no part of it can come closer than 10 feet to the power wires.

15. Electrical and RF Safety T0C • RF hazards, RF heating hazards, Proximity to antennas, Hand held safety • VHF and UHF radio signals are non-ionizing radiation. • Radio waves can cause injury to the human body only if the combination of signal strength and frequency cause excessive power to be absorbed. • If a person accidentally touched your antenna while you were transmitting they might receive a painful RF burn injury.

16. Electrical and RF Safety T0C • Radiation exposure, exposure to others • The factors that affect the RF exposure of people near an amateur transmitter are: • Frequency and power level of the RF field • Distance from the antenna to a person • Radiation pattern of the antenna o All of these answers are correct • The frequency of an RF source must be considered when evaluating RF radiation exposure because the human body absorbs more RF energy at some frequencies than others.

17. Electrical and RF Safety T0C • Radiation exposure, exposure to others (cont) • Some actions amateur operators might take to prevent exposure to RF radiation in excess of FCC supplied limits include: • Alter antenna patterns • Relocate antennas • Change station parameters such as frequency or power • All of these answers are correct

18. Electrical and RF Safety T0C • Recognized safe power levels • The maximum power level that an amateur radio station may use at frequencies above 30 MHz before an RF exposure evaluation is required is 50 watts PEP at the antenna. • You can determine that your station complies with FCC RF exposure regulations: • By calculation based on FCC OET Bulletin 65 • By calculation based on computer modeling • By measurement of field strength using calibrated equipment All of these choices are correct

19. Electrical and RF Safety T0C • Recognized safe power levels (cont) • Milliwatts per square centimeter is the unit of measurement used to measure RF radiation exposure. • The duty cycle is one of the factors used to determine safe RF radiation exposure levels because it takes into account the amount of time the transmitter is operating. • You make sure your station stays in compliance with RF safety regulations by re-evaluating the station whenever an item of equipment is changed.

20. Take Aways • Guard against electrical shock • 3-wire plugs • Ground-fault • Common ground • Emergency disconnect…tell everyone where it is. • Lowest voltage for shock … 30 volts • Lowest current is … 100 milliamperes • Stored charge in large capacitors can cause shock with power supply off • Fuses interrupt power in overload • 20 amp replacing a 5 amp … potential fire • Green wire of 3-wire is ground

21. Take Aways (cont) • Lightning protection • Disconnect antenna • Unplug power from AC • Stop using equipment… move to another room • Fire prevention … most important reason for lightning protection • Recharge 12-volt battery … connect to car … run engine • Storage battery charge or discharge too quickly … overheat/explode

22. Take Aways (cont) • 12-volt hazards • Contain acid … spill .. Cause injury • Short circuits … damage wiring … fire • Explosive gas if not vented • Antenna location … away from people • Hard hat … safety glasses … on ground helping • Use safety belt & safety glasses before climbing tower

23. Take Aways (cont) • Before climbing a tower • Arrange helper/observer • Inspect damage/loose hardware • No electrical storms nearby • Guy wires …. Install per manufacturer • Never climb a crank-up tower extended • Stainless hardware much less likely to corrode • 8 foot ground rods … per tower leg … bonded to tower

24. Take Aways (cont) • Stay clear of overhead electric wires … putting up tower • Safe distance … if falls … no closer than 10 feet • VHF/UHF non-ionizing radiation • Excessive power absorbed can cause injury to body • Touch antenna during transmission … possible RF burn • Body absorbs more RF energy at some frequencies than others …. Source must be considered

25. Take Aways (cont) • Factors affecting RF exposure … in excess of FCC limits • Frequency and power level • Distance from antenna • Radiation pattern of antenna • Actions to prevent exposure • Alter antenna patterns • Relocate antenna • Change station parameters … power or frequency

26. Take Aways (cont) • RF exposure above 30 MHz … 50 watts PEP at antenna • Determine FCC RF exposure • FCC OET Bulletin 65 • Calculations on computer modeling • Field strength meter • Milliwatts sq/centimeter … measure RF radiation exposure • Duty cycle … amount of time transmitter is operating • Change equipment … re-evaluate RF safety regs to stay in compliance

27. Element 2 Technician Class Question PoolT0 Valid July 1, 2006 Through June 30, 2010

28. T0A01 What is a commonly accepted value for the lowest voltage that can cause a dangerous electric shock? • 12 volts • 30 volts • 120 volts • 300 volts

29. T0A02 What is the lowest amount of electrical current flowing through the human body that is likely to cause death? • 10 microamperes • 100 milliamperes • 10 amperes • 100 amperes

30. T0A03 What is connected to the green wire in a three-wire electrical plug? • Neutral • Hot • Ground • The white wire

31. T0A04 What is the purpose of a fuse in an electrical circuit? • To make sure enough power reaches the circuit • To interrupt power in case of overload • To prevent television interference • To prevent shocks

32. T0A05 What might happen if you install a 20-ampere fuse in your transceiver in the place of a 5-ampere fuse? • The larger fuse would better protect your transceiver from using too much current • The transceiver will run cooler • Excessive current could cause a fire • The transceiver would not be able to produce as much RF output

33. T0A06 What is a good way to guard against electrical shock at your station? • Use 3-wire cords and plugs for all AC powered equipment • Connect all AC powered station equipment to a common ground • Use a ground-fault interrupter at each electrical outlet • All of these answers are correct

34. T0A07 What is the most important thing to consider when installing an emergency disconnect switch at your station? • It must always be as near to the operator as possible • It must always be as far away from the operator as possible • Everyone should know where it is and how to use it • It should be installed in a metal box to prevent tampering

35. T0A08 What precautions should be taken when a lightning storm is expected? • Disconnect the antenna cables from your station and move them away from your radio equipment • Unplug all power cords from AC outlets • Stop using your radio equipment and move to another room until the storm passes • All of these answers are correct

36. T0A09 What is one way to recharge a 12-volt battery if the commercial power is out? • You cannot recharge a battery unless the power is back on • Add water to the battery • Connect the battery to a car's battery and run the engine • Take your battery to the utility company for a recharge

37. T0A10 What kind of hazard is presented by a conventional 12-volt storage battery? • It contains dangerous acid that can spill and cause injury • Short circuits can damage wiring and possibly cause a fire • Explosive gas can collect if not properly vented • All of these answers are correct

38. T0A11 What can happen if a storage battery is charged or discharged too quickly? • The battery could overheat and give off dangerous gas or explode • The terminal voltage will oscillate rapidly • The warranty will be voided • The voltage will be reversed

39. T0A12 What is the most important reason to have a lightning protection system for your amateur radio station? • Lower insurance rates • Improved reception • Fire prevention • Noise reduction

40. T0A13 What kind of hazard might exist in a power supply when it is turned off and disconnected? • Static electricity could damage the grounding system • Circulating currents inside the transformer might cause damage • The fuse might blow if you remove the cover • You might receive an electric shock from stored charge in large capacitors

41. T0B01 Why should you wear a hard hat and safety glasses if you are on the ground helping someone work on an antenna tower? • It is required by FCC rules • To keep RF energy away from your head during antenna testing • To protect your head and eyes in case something accidentally falls from the tower • It is required by the electrical code

42. T0B02 What is a good precaution to observe before climbing an antenna tower? • Turn on all radio transmitters • Remove all tower grounding connections • Put on your safety belt and safety glasses • Inform the FAA and the FCC that you are working on a tower

43. T0B03 What should you do before you climb a tower? • Arrange for a helper or observer • Inspect the tower for damage or loose hardware • Make sure there are no electrical storms nearby • All of these answers are correct

44. T0B04 What is an important consideration when putting up an antenna? • Carefully tune it for a low SWR • Make sure people cannot accidentally come into contact with it • Make sure you discard all packing material in a safe place • Make sure birds can see it so they don't fly into it

45. T0B05 What must be considered when erecting an antenna near an airport? • The maximum allowed height with regard to nearby airports • The possibility of interference to aircraft radios • The radiation angle of the signals it produces • The polarization of signal to be radiated

46. T0B06 What is the most important safety precaution to observe when putting up an antenna tower? • Install steps on the tower for safe climbing • Insulate the base of the tower to avoid lightning strikes • Ground the base of the tower to prevent lightning strikes • Look for and stay clear of any overhead electrical wires

47. T0B07 How should the guy wires for an antenna tower be installed? • So each guy wire anchor point has an even number of wires • So that no guy wire is more than 25 feet long • Each guy wire must be pulled as tight as possible • In accordance with the tower manufacturer's instructions

48. T0B08 What is a safe distance from a power line to allow when installing an antenna? • Half the width of your property unless the wires are at least 23 feet high • 12.5 feet in most metropolitan areas • 36 meters plus 1/2 wavelength at the operating frequency • So that if the antenna falls unexpectedly, no part of it can come closer than 10 feet to the power wires

49. T0B09 What is the most important safety rule to remember when using a crank-up tower? • This type of tower must never be painted • Crank up towers must be raised and lowered frequently to keep them properly lubricated • Winch cables must be specially rated for use on this type of tower • A crank-up tower should never be climbed unless it is in the fully lowered position

50. T0B10 Why is stainless steel hardware used on many antennas instead of other metals? • Stainless steel is a better electrical conductor • Stainless steel weighs less than other metals • Stainless steel parts are much less likely to corrode • Stainless steel costs less than other metals