Solid State Shortwave Receivers For Beginners - The Listeners Guide

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Components List for Fig.32 R1 3.3k R2 680 ohms C1 22nf plastic foil. Tr1 2N3819 S1 S.P.S.T. toggle. Hardware. Components List for Fig.33 R1 680 ohms Tr1 2N38l9. S1 S.P.S.T. toggle Hardware. Tuned R.F. Amplifier A tuned R.F. amplifier will provide more gain than its untuned counterpart. When used as an external adjunct to a receiver this type of unit is usually called a ‘preselector’. Unlike an untuned circuit which amplifies all the S.W. aerial signals, a preselector only amplifies over a relatively narrow bandwidth. Thus, despite its higher gain, it is less prone to overload the receiver. 84
Components List for Fig.34 R1 680 ohms R2 680 ohms C1 5.6nf ceramic. C2 22nf plastic foil. C3 22pf plastic foil. Tr1 2N3819. VC1 365pf air spaced (type 0). L1 10mH. (Repanco CH4). T1 Denco Green D.P. coils Ranges 3, 4, and 5. S1 S.P.S.T. toggle switch. Hardware. Fig.34 shows the circuit diagram of a simple preselector which uses a Jugfet common source amplifier. This is very much the same as the circuit of Fig.30, the main difference being that a tuned circuit is used at the input instead of a simple resistor. VC1 is the tuning control and this is adjusted to peak received signals. It will need some readjustment each time the receiver’s tuning is altered significantly. It was found to be necessary to include the supply decoupling network consisting of R1 and C1, as without this there was a tendency for the circuit to become unstable. 85
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Solid State Short Wave Receivers Fo
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SOLID STATE SHORT WAVE RECEIVERS FO
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CONTENTS Page CHAPTER 1 Frequency S
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CHAPTER 1 There is a strange fascin
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Propagation The reasons for the ama
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41 Metres 7.1 to 7.3 MHZ 31 Metres
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e. A length of wire is connected to
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Crystal Set CHAPTER 2 Ultra Simple
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Components List for Fig.6 T1 Denco
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To those unfamiliar with this metho
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The completed chassis and panel are
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crystal set is not very high. This
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ted it would look something like th
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eceivers it does have too low a val
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to have on. connection earthed. In
Page 35 and 36: It is very worthwhile experimenting
Page 37 and 38: layer, acts as the dielectric of th
Page 39 and 40: level that reaches the detector of
Page 41: CHAPTER 3 General Purpose Receivers
Page 44 and 45: The output of Tr1 is developed acro
Page 47 and 48: Components List for Fig. 18 Resisto
Page 50 and 51: Components List for Fig.19 Resistor
Page 55 and 56: A.F. noise from Tr2 from reaching s
Page 57: The gain of the I.C. is fixed at ap
Page 60: Like MOSFETS, CMOS I.C.s can be dam
Page 63: CHAPTER 4 Portable Receivers One mi
Page 66: Normally the telescopic aerial shou
Page 72 and 73: A.M. Signal It will be helpful to f
Page 74 and 75: As should be apparent by now, if th
Page 78 and 79: the mains earth (regardless of whet
Page 80 and 81: Blank page 80
Page 82 and 83: Components List for Fig.30 R1 3.3k
Page 86 and 87: Apart from increasing the sensitivi
Page 89 and 90: Components List for Fig.36 R1 390 o
Page 91 and 92: prevent the oscillator from operati
Page 93: BERNARDS No 222 Solid State Short W
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Solid State Shortwave Receivers For Beginners - The Listeners Guide

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