Radio and Electronics Cookbook

331 Pages·2001·6.27 MB·English

by  George Brown

Radio and Electronics Cookbook

Radio and Electronics
Cookbook
Edited by
Dr George Brown, CEng, FIEE, M5ACN
OXFORD AUCKLAND BOSTON JOHANNESBURG MELBOURNE NEW DELHI
Newnes
An imprint of Butterworth-Heinemann
Linacre House, Jordan Hill, Oxford OX2 8DP
225 Wildwood Avenue, Woburn, MA 01801-2041
A division of Reed Educational and Professional Publishing Ltd
A member of the Reed Elsevier plc group
First published 2001
© Radio Society of Great Britain 2001
All rights reserved. No part of this publication may be reproduced in
any material form (including photocopying or storing in any medium by
electronic means and whether or not transiently or incidentally to some
other use of this publication) without the written permission of the
copyright holder except in accordance with the provisions of the Copyright,
Designs and Patents Act 1988 or under the terms of a licence issued by the
Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London,
England W1P 0LP. Applications for the copyright holder’s written
permission to reproduce any part of this publication should be addressed
to the publishers
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library
ISBN 0 7506 5214 4
RSGB
Lambda House
Cranborne Road
Potters Bar
Herts
EN6 3JE
Composition by Genesis Typesetting, Laser Quay, Rochester, Kent
Printed and bound in Great Britain
Contents
Preface ix
1. A medium-wave receiver 1
2. An audio-frequency amplifier 4
3. A medium-wave receiver using a ferrite-rod aerial 9
4. A simple electronic organ 12
5. Experiments with the NE555 timer 17
6. A simple metronome 21
7. What is a resistor? 24
8. Waves – Part 1 27
9. A beat-frequency oscillator 31
10. What is a capacitor? 34
11. Waves – Part 2 38
12. An LED flasher 41
13. Waves – Part 3 44
14. Choosing a switch 46
15. An aerial tuning unit for a receiver 49
16. A simple 2m receiver preamplifier 52
17. Receiving aerials for amateur radio 54
18. The Colt 80m receiver – Part 1 58
19. A crystal radio receiver 62
20. The varactor (or varicap) diode 64
21. A portable radio for medium waves 65
22. The Colt 80m receiver – Part 2 70
v
Contents
23. A simple transistor tester 73
24. An introduction to transmitters 77
25. The Colt 80m receiver – Part 3 81
26. A two-way Morse practice system 88
27. The Colt 80m receiver – Part 4 91
28. A simple crystal set 95
29. A crystal calibrator 100
30. A simple short-wave receiver – Part 1 104
31. A fruit-powered medium-wave radio 106
32. A capacitance bridge 109
33. A simple short-wave receiver – Part 2 113
34. A basic continuity tester 117
35. A charger for NiCad batteries 119
36. An 80 metre crystal-controlled CW transmitter 123
37. A solar-powered MW radio 129
38. A receiver for the 7MHz amateur band 133
39. Diodes for protection 137
40. An RF signal probe 140
41. An RF changeover circuit 142
42. A low-light indicator 146
43. A J-pole aerial for 50 MHz 149
44. Measuring light intensity – the photometer 153
45. A 70cm Quad loop aerial 156
46. A UHF field strength meter 160
47. Christmas tree LEDs 162
48. An audio signal injector 166
49. Standing waves 168
50. A standing-wave indicator for HF 170
51. A moisture meter 174
52. Simple aerials 177
53. A breadboard 80cm CW transmitter 182
vi
Contents
54. A 7-element low-pass filter for transmitters 186
55. Radio-frequency mixing explained 189
56. A voltage monitor for a 12V power supply 192
57. A 1750Hz toneburst for repeater access 196
58. A circuit for flashing LEDs 201
59. Digital logic circuits 205
60. A resistive SWR indicator 210
61. An audio filter for CW 213
62. An electronic die 215
63. The absorption wavemeter 222
64. An HF absorption wavemeter 224
65. A vertical aerial for 70cm 228
66. A UHF corner reflector aerial 230
67. A switched dummy load 234
68. A simple Morse oscillator 238
69. A bipolar transistor tester 240
70. The ‘Yearling’ 20m receiver 245
71. Adding the 80 metre band to the Yearling receiver 251
72. How the Yearling works 255
73. A field strength meter 258
74. Preselector for a short-wave receiver 261
75. An audible continuity tester 265
76. An experimental 70cm rhombic aerial 268
77. Water level alarm 272
78. A delta loop for 20 metres 275
79. A simple desk microphone 279
80. Morse oscillator 284
81. A simple 6m beam 287
82. An integrated circuit amplifier 291
83. A novice ATU 293
84. CW QRP transmitter for 80 metres 297
vii
Contents
85. An audio booster for your hand-held 303
86. A grid dip oscillator 306
87. A CW transmitter for 160 to 20 metres 312
88. Matching the end-fed random-wire aerial 315
viii
Preface
Although we are surrounded by sophisticated computerised gadgets these
days, there is still a fascination in putting together a few resistors, capacitors
and the odd transistor to make a simple electronic circuit. It is really
surprising how a handful of components can perform a useful function, and
the satisfaction of having built it yourself is incalcuable.
This book aims to provide a wide variety of radio and electronic projects,
from something that will take a few minutes to a more ambitious weekend’s
worth. Various construction techniques are described, the simplest requiring
no more than a small screwdriver, the most complex involving printed
circuit boards.
Originally published by the Radio Society of Great Britain, the projects were
all chosen to be useful and straightforward, with the emphasis on
practicality. In most cases the workings of the circuit are described, and the
projects are backed up by small tutorials on the components and concepts
employed. In the 21st century it may seem strange that few of the published
circuits use integrated circuits (chips). This is intentional as it is much easier
to understand how the circuit works when using discrete components.
Anyone buying the Radio and Electronics Cookbook will find that it will
lead to hours of enjoyment, some very useful and entertaining gadgets, and
increased knowledge of how and why electronics circuits work, and a great
sense of satisfaction. Beware, electronic construction is addictive!
WARNING: This book contains construction details of transmitters.
It is illegal to operate a transmitter without the appropriate licence.
Information on how to obtain an Amateur Radio Licence can be
obtained from the Radiocommunications Agency, tel. [phone]
0160.