ExtraClassSylalbus2009jan-AD7FO

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Rev 2.02 SUBELEMENT E9 -– ANTENNAS AND TRANSMISSION LINES [8 Exam Questions -- 8 Groups] E9A - Isotropic and gain antennas: definition; used as a standard for comparison; radiation pattern; basic antenna parameters: radiation resistance and reactance, gain, beamwidth, efficiency E9A01 An isotropic Antenna is a theoretical antenna used as a reference for antenna gain. An isotropic source radiates equally in all directions E9A02 A 1/2-wavelength dipole has 2.15 dB gain compared to an isotropic antenna. Actually 2.14 dB gain, the test question answer is rounded to 2.15 dB E9A03 An Isotropic antenna has no (zero) gain in any direction. E9A04 One needs to know the feed point impedance of an antenna to match impedances for maximum power transfer from a feed line. E9A05 Antenna height and conductor length/diameter ratio, and location of nearby conductive objects determine the radiation resistance of an antenna. E9A06 The term for the ratio of the radiation resistance of an antenna to the total resistance of the system is antenna efficiency. Efficiency = (RR / Rt ) x 100% With RR= radiation resistance and Rt=Total Resistance E9A07 Radiation resistance plus ohmic resistance are included in the total resistance of an antenna system. E9A08 A dipole constructed from one wavelength of wire forming a very thin loop is a folded dipole antenna. E9A09 Antenna gain is the numerical ratio relating the radiated signal strength of an antenna in the direction of maximum radiation to that of a reference antenna. Gain is generally expressed in dB relative to either an Isotropic source or a dipole. Jack Tiley <strong>AD7FO</strong> Page 86 3/15/2009
Rev 2.02 E9A10 Antenna bandwidth is the frequency range over which an antenna satisfies a performance requirement. Performance examples would be – Gain - SWR or impedance - Beam width - etc E9A11 Antenna efficiency is calculated by (radiation resistance / total resistance) x 100%. Can also be calculated by the equation: Efficiency = Radiated Power / Input power E9A12 The efficiency of an HF quarter-wave grounded vertical antenna can be improved by installing a good radial system. E9A13 Soil conductivity is the most important factor in determining ground losses for a ground-mounted vertical antenna operating in the 3-30 MHz range. E9A14 If an antenna has 3.85 dB gain over a 1/2-wavelength dipole then it has 6 dB gain over an isotropic antenna. The gain over isotropic source for an antenna with a 3.85 dB gain over a dipole antenna would be an additional 2.14 dB of gain. Remember dipole gain over an isotropic source is 2.14 dB or 3.85 dB +1.14dB or 5.99dB E9A15 An antenna has 9.85 dB of gain over a 1/2-wavelength dipole when it has 12 dB of gain over an isotropic antenna. Remember that a dipole has 2.14 dB of gain as referenced to an isotropic antenna. 12 dB -2.14 dB or gain =9.86dB E9A16 The radiation resistance of an antenna is the value of a resistance that would dissipate the same amount of power as that radiated from an antenna. E9B - Antenna patterns: E and H plane patterns; gain as a function of pattern; antenna design (computer modeling of antennas); Yagi antennas E9B01 The orientation of its electric field (E Field) determines the free-space polarization of an antenna. Jack Tiley <strong>AD7FO</strong> Page 87 3/15/2009
Page 1 and 2:
Rev 2.02 Preparing for the Extra cl
Page 3 and 4:
Rev 2.02 Guide to using this syllab
Page 5 and 6:
Rev 2.02 SUBELEMENT E4 -- AMATEUR R
Page 7 and 8:
Rev 2.02 ELEMENT 4 - EXTRA CLASS QU
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Rev 2.02 E1A09 (Band Plan Chart) Th
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Rev 2.02 E1B13 (FCC Rules) Communic
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Rev 2.02 E1D08 (FCC Rules) The 2 me
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Rev 2.02 E1E20 (FCC Rules) You must
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Rev 2.02 SUBELEMENT E2 - OPERATING
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Rev 2.02 E2A13 Geosynchronous satel
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Rev 2.02 E2B17 Immunity from fading
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Rev 2.02 E2D02 The definition of
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Rev 2.02 SUBELEMENT E3 -- RADIO WAV
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Rev 2.02 E3C01 Auroral activity cau
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Rev 2.02 E4A06 A spectrum analyzer
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Rev 2.02 E4B09 High impedance input
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Rev 2.02 E4C06 If t he thermal nois
Page 35 and 36: Rev 2.02 E4D11 Third-order intermod
Page 37 and 38: Rev 2.02 SUBELEMENT E5 -- ELECTRICA
Page 39 and 40: Rev 2.02 E5B Time constants and pha
Page 41 and 42: Rev 2.02 Example 2: To find the ang
Page 43 and 44: Rev 2.02 j 50 -j 25 E5B12 The phase
Page 45 and 46: Rev 2.02 j 600 -j300 E5C04 In polar
Page 47 and 48: Rev 2.02 Parallel circuit solutions
Page 49 and 50: Rev 2.02 R=300 Ω XL= (2 π FL) or
Page 51 and 52: Rev 2.02 Power Factor represents th
Page 53 and 54: Rev 2.02 SUBELEMENT E6 -- CIRCUIT C
Page 55 and 56: Rev 2.02 Field-effect transistors e
Page 57 and 58: Rev 2.02 E6B12 Junction diodes are
Page 59 and 60: Rev 2.02 E6D02 Cathode ray tube (CR
Page 61 and 62: Rev 2.02 E6E04 The technique used t
Page 63 and 64: Rev 2.02 E6F07 Cadmium sulfide will
Page 65 and 66: Rev 2.02 E7A07 An AND gate produces
Page 67 and 68: Rev 2.02 When a Class C rather than
Page 69 and 70: Rev 2.02 E7C01 In a low-pass filter
Page 71 and 72: Rev 2.02 E7D02 One characteristic o
Page 73 and 74: Rev 2.02 E7E05 A pre-emphasis netwo
Page 75 and 76: Rev 2.02 E7F08 One purpose of a mar
Page 77 and 78: Rev 2.02 E7G17 The typical output i
Page 79 and 80: Rev 2.02 E7H19 A phase-locked loop
Page 81 and 82: Rev 2.02 E8A06 The approximate rati
Page 83 and 84: Rev 2.02 E8B13 In time division mul
Page 85: Rev 2.02 E8D07 An electromagnetic w
Page 89 and 90: Rev 2.02 E9B10 The “Method of Mom
Page 91 and 92: Rev 2.02 E9C09 The elevation angle
Page 93 and 94: Rev 2.02 E9D09 An advantage of usin
Page 95 and 96: Rev 2.02 E9E08 An SWR greater than
Page 97 and 98: Rev 2.02 E9F11 A 1/8-wavelength tra
Page 99 and 100: Rev 2.02 E9H05 The main drawback of
Page 101 and 102: Rev 2.02 SUBELEMENT E0 -- SAFETY [1
Page 103 and 104: Rev 2.02 Jack Tiley AD7FO Page 103
Page 105 and 106: Rev 2.02 Capacitors in series C= __
Page 107 and 108: Rev 2.02 Impedance of complex serie
Page 109 and 110: Rev 2.02 Calculating Component valu
Page 111 and 112: Rev 2.02 AC Voltage Calculations Th
Page 113: Rev 2.02 Jack Tiley AD7FO Page 113
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