Amateur Radio Technician Class Elment 2 Course …4658：業(yè)余無(wú)線(xiàn)電技師班2元課程……

1、general licensing classgeneral licensing classg0a g0b g0a g0b electrical and rf safetyelectrical and rf safetyyour organization and dates here2general class element 3 course presentationgeneral class element 3 course presentationelement 3 sub-elementselement 3 sub-elementsg1 commissions rulesg1 comm

2、issions rulesg2 operating proceduresg2 operating proceduresg3 radio wave propagationg3 radio wave propagationg4 amateur radio practicesg4 amateur radio practices g5 electrical principlesg5 electrical principlesg6 circuit componentsg6 circuit componentsg7 practical circuitsg7 practical circuitsg8 sig

3、nals and emissionsg8 signals and emissionsg9 antennasg9 antennasg0 electrical and rf safetyg0 electrical and rf safety3electrical and rf safetyelectrical and rf safety one way that rf energy can affect human body tissue is that it it heats body tissueheats body tissue. (g0a01) the following properti

4、es are important in estimating whether an rf signal exceeds the maximum permissible exposure (mpe) (g0a02) its duty cycle its frequency its power densitynever stand in front of a microwave feedhorn antennaon transmit, it radiates a highly concentrated beam of rf energy all of these choices are corre

5、ct.4electrical and rf safetyelectrical and rf safety you can determine that your station complies with fcc rf exposure regulations: (g0a03) by calculation based on fcc oet bulletin 65 by calculation based on computer modeling by measurement of field strength using calibrated equipment time averaging

6、 in reference to rf radiation exposure means the total rf exposure averaged over a certain time. (g0a04)the general equation for time averaging exposure equivalence is:sexp texp = slimit tavgall of these choices are correct.5electrical and rf safetyelectrical and rf safety if an evaluation of your s

7、tation shows rf energy radiated from your station exceeds permissible limits you must take action to prevent human exposure to the excessive rf fields. (g0a05) (g0a06 deleted by qpc) when evaluating rf exposure, a lower transmitter duty cycle a lower transmitter duty cycle permits greater short-term

8、 exposure levelspermits greater short-term exposure levels. (g0a07) an amateur operator must perform a routine rf exposure perform a routine rf exposure evaluationevaluation to ensure compliance with rf safety regulations when transmitter power exceeds levels specified in part 97.13. (g0a08)duty cyc

9、le6electrical and rf safetyelectrical and rf safety a calibrated field-strength meter with a calibrated antenna a calibrated field-strength meter with a calibrated antenna can be used to accurately measure an rf field. (g0a09) jerrod model 704belectro-metrics em-7530homebrew by ka7oei of utah amateu

10、r radio club7electrical and rf safetyelectrical and rf safety if an evaluation shows that a neighbor might receive more than the allowable limit of rf exposure from the main lobe of a directional antenna, take take precautions to ensure that the antenna precautions to ensure that the antenna cannot

11、be pointed in their directioncannot be pointed in their direction. (g0a10) if you install an indoor transmitting antenna, make sure that mpe limits are make sure that mpe limits are not exceeded in occupied areasnot exceeded in occupied areas. (g0a11) mpe = maximum permissible exposure turn off the

12、transmitter and disconnect turn off the transmitter and disconnect the feed line the feed line whenever you make adjustments or repairs to an antenna. (g0a12)8electrical and rf safetyelectrical and rf safety when installing a ground-mounted antenna, it should be installed it should be installed so n

13、o one can be exposed to rf radiation in excess of maximum so no one can be exposed to rf radiation in excess of maximum permissible limitspermissible limits. (g0a13) only the hot wires only the hot wires in a four-conductor line cord should be attached to fuses or circuit breakers in a device operat

14、ed from a 240-vac single-phase source. (g0b01)notice wood safety fence. keep a safe distance away from antenna during all transmissions.9electrical and rf safetyelectrical and rf safety according to the code, awg number 12 awg number 12 is the minimum wire size that may be safely used for a circuit

15、that draws up to 20 amperes20 amperes of continuous current. (g0b02) 15 amperes 15 amperes is the size of fuse or circuit breaker that would be appropriate to use with a circuit that uses awg number 14awg number 14 wiring. (g0b03)10electrical and rf safetyelectrical and rf safety danger of carbon mo

16、noxide poisoning danger of carbon monoxide poisoning is a primary reason for not placing a gasoline-fueled generator inside an occupied area. (g0b04) carbon monoxide is serious stuff, dont take it lightly!11electrical and rf safetyelectrical and rf safety current flowing from one or more of the hot

17、wires directly to current flowing from one or more of the hot wires directly to ground ground will cause a g ground f fault c circuit i interrupter (gfcigfci) to disconnect the 120 or 240 volt ac line power to a device. (g0b05) 12rf & electrical safety13electrical and rf safetyelectrical and rf

18、safety the metal enclosure of every item of station equipment must be grounded because it ensures that hazardous voltages cannot appear it ensures that hazardous voltages cannot appear on the chassison the chassis. (g0b06) enclosures, chassis, and all metal housings should be common grounded.14elect

19、rical and rf safetyelectrical and rf safety one of the practices that should be observed for safety when climbing on a tower using a safety belt or harness is to always always attach the belt safety hook to the belt d-ring with the hook attach the belt safety hook to the belt d-ring with the hook op

20、ening away from the toweropening away from the tower. (g0b07) always disconnect the feedline from the transmitter before going up a tower to work on antennaprevents accidental rf radiation exposure.always think safety first when working on towers.15electrical and rf safetyelectrical and rf safety an

21、y person preparing to climb a tower that supports electrically powered devices should make sure all circuits that supply power make sure all circuits that supply power to the tower are locked out and taggedto the tower are locked out and tagged. (g0b08) soldered joints should not be used with the wi

22、res that connect the base of a tower to a system of ground rods because a a soldered joint will likely be destroyed by the heat of a soldered joint will likely be destroyed by the heat of a lightning strike.lightning strike. (g0b09) one danger from lead-tin solder is that lead can contaminate lead c

23、an contaminate food if hands are not washed carefully after handlingfood if hands are not washed carefully after handling. (g0b10) 16electrical and rf safetyelectrical and rf safety good engineering practice for lightning protection grounds includes bonding them together with all other groundsbondin

24、g them together with all other grounds. (g0b11) notice green cable as common ground under floor and connected to building column.notice wide copper straps17electrical and rf safetyelectrical and rf safety the purpose of a transmitter power supply interlock is to ensure to ensure that dangerous voltages are removed if the cabinet is openedthat dangerous voltages are removed if the cabinet is opened. (g0b12) when po