Amateur Radio Technician Class Element 2 Course …：业余无线电技师班元2课程….ppt

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1、TechnicianLicensingClassTechFrequenciesLakeAreaRadioKlubSpring20122AmateurRadioTechnicianClassElement2CoursePresentationELEMENT2SUB-ELEMENTS(Groupings)AboutHamRadioCallSignsControlMindtheRulesTechFrequenciesYourFirstRadioGoingOnTheAir!RepeatersEmergency!WeakSignalPropagation3AmateurRadioTech

2、nicianClassElement2CoursePresentationELEMENT2SUB-ELEMENTS(Groupings)TalktoOuterSpace!YourComputerGoesHamDigital!Multi-ModeRadioExcitementRunSomeInterferenceProtectionElectrons–GoWiththeFlow!It’stheLaw,perMr.Ohm!GoPictureThese!AntennasFeedMewithSomeGoodCoax!SafetyFirst!4TechFrequenciesT5C6RFi

3、stheabbreviationthatreferstoradiofrequencysignalsofalltypes.Term“RF”referstoradiofrequency5TechFrequenciesT3A7Electromagneticwavescarryradiosignalsbetweentransmittingandreceivingstations.T3B3Electricandmagneticfieldsarethetwocomponentsofaradiowave.T3B4Radiowavestravelthroughfreespaceatthespee

4、doflight.T3B11Theapproximatevelocityofaradiowaveasittravelsthroughfreespaceis300,000,000meterspersecond.T5C5Hertzistheunitoffrequency.Theyareatrightanglestoeachotherandtogetherarecalled“electromagnetic”radiowaves6TechFrequenciesT5B7Ifafrequencyreadoutcalibratedinmegahertzshowsareadingof3.525M

5、Hz,itwouldshow3525kHzifitwerecalibratedinkilohertz.T3B1Thenameforthedistancearadiowavetravelsduringonecompletecycleiswavelength.Keywords:distanceandwavelengthT3B7Thepropertyofradiowavesoftenusedtoidentifythedifferentfrequencybandsistheapproximatewavelength.Wavelengthoftheband:2meters;20meters

6、;40meters,etcCarrier,Frequency,Cycle,andWavelength7TechFrequenciesT3B5Thewavelengthofaradiowaverelatestoitsfrequencyinversely,asthewavelengthgetsshorterthefrequencyincreases.Higherinfrequencytheshorterthedistancebetweeneachwave.T3B6Theformulaforconvertingfrequencytowavelengthinmetersisthewave

7、lengthinmetersequals300dividedbyfrequencyinmegahertz.(OneanswerendswithwordMegahertz)ConversionsBetweenWavelengthandFrequencyConvertingFrequencytoWavelengthConvertingWavelengthtoFrequencyTofindwavelength()inmeters,ifyouknowfre3quency(f)inmega