ExtraClassSylalbus2009jan-AD7FO

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Rev 2.02 E9C17 The main effect of placing a vertical antenna over an imperfect ground is that it reduces low-angle radiation E9D - Directional antennas: gain; satellite antennas; antenna beamwidth; losses; SWR bandwidth; antenna efficiency; shortened and mobile antennas; grounding E9D01 The gain of a parabolic dish antenna increases 6 dB when the operating frequency is doubled. E9D02 One way to produce circular polarization, when using linearly polarized antennas, is to arrange two Yagi antennas perpendicular to each other with the driven elements at the same point on the boom and fed 90 degrees out of phase. E9D03 The beamwidth of an antenna decreases as the gain is increased. The antenna becomes more directional E9D04 It desirable for a ground-mounted satellite communications antenna system to be able to move in both azimuth and elevation in order to track the satellite as it orbits the earth. E9D05 For a shortened vertical antenna, a loading coil is placed near the center of the vertical radiator to minimize losses and produce the most effective performance. E9D06 An HF mobile antenna loading coil should have a high ratio of reactance to resistance to minimize losses. E9D07 A disadvantage of using a multi-band trapped antenna is that it might radiate harmonics. E9D08 The bandwidth of an antenna is decreased as it is shortened through the use of loading coils. Jack Tiley <strong>AD7FO</strong> Page 92 3/15/2009
Rev 2.02 E9D09 An advantage of using top loading in a shortened HF vertical antenna is improved radiation efficiency. E9D10 The approximate feed-point impedance at the center of a folded dipole antenna is 300 ohms. E9D11 A loading coil is often used with an HF mobile antenna to cancel capacitive reactance. E9D12 An advantage of using a trapped antenna is that It may be used for multi-band operation. E9D13 The resistance decreases and the capacitive reactance increases at the base feed-point of a fixed-length HF mobile antenna as the frequency of operation is lowered. E9D14 A thin, flat copper strap several inches wide would be best for minimizing losses in a station's RF ground system. The thin copper strap will have lower inductive reactance making it a lower loss to the earth ground point. E9D15 A connection to 3 or 4 interconnected ground rods driven into the earth would provide the best RF ground for your station. E9E Matching: matching antennas to feed lines; power dividers E9E01 The delta matching system matches a high-impedance transmission line to a lower impedance antenna by connecting the line to the driven element in two places spaced a fraction of a wavelength each side of element center. Jack Tiley <strong>AD7FO</strong> Page 93 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
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Rev 2.02 SUBELEMENT E4 -- AMATEUR R
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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
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Rev 2.02 E4D11 Third-order intermod
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Rev 2.02 SUBELEMENT E5 -- ELECTRICA
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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 and 86: Rev 2.02 E8D07 An electromagnetic w
Page 87 and 88: Rev 2.02 E9A10 Antenna bandwidth is
Page 89 and 90: Rev 2.02 E9B10 The “Method of Mom
Page 91: Rev 2.02 E9C09 The elevation angle
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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ExtraClassSylalbus2009jan-AD7FO

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