How to Build Advanced Short Wave Receivers - The Listeners Guide

More documents

Recommendations

Info

CHAPTER THREE - DOUBLE CONVERSION RECEIVER Alternative System . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 2nd Mixer/Osc. Circuit . . . . . . . . . . . . . . . . . . . . . . . . 77 Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 Bandswitching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 CHAPTER FOUR - ADD-ON CIRCUITS Q Multiplier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 Crystal Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Mechanical Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 ‘S’ Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 Noise Limiter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 C.W. Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 Variable Notch Filter . . . . . . . . . . . . . . . . . . . . . . . . . 101 Product Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Mains P.S.U. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 Crystal Calibrator . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 Using the Calibrator . . . . . . . . . . . . . . . . . . . . . . . . . 111 Preselector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 Semiconductor Leadout Data . . . . . . . . . . . . . . . . . . 117 Special Note for Overseas Readers . . . . . . . . . . . . . . 118
CHAPTER ONE ADVANCED S.W. RECEIVERS Although there is a tendency for short wave listeners and Radio Amateurs to use ready made equipment these days, greater satisfaction and enjoyment can be gained from the hobby by using home constructed equipment. Using ready made S.W. gear does not give any insight into the way in which the apparatus functions, and by building ones own equipment it is virtually inevitable that a reasonable understanding of the techniques involved will be grasped. Such an understanding is very helpful when it comes to actually using a finished receiver, and it enables the operator to obtain optium results from the set. The reason that commercially produced equipment has increased in popularity is probably largely due to the high standard of finish that is achieved. It must be admitted that it is difficult for the home constructor to equal commercial standards in this respect, but if due care and attention is taken, it is possible to obtain a standard which. will satisfy even the most critical. As far as performance is concerned, there is absolutely no reason why a home constructed receiver should not have a level of performance which is at least equal to that of a commercially built receiver of similar complexity. Further. more, the home constructed receiver is likely to cost very much less than its ready made equivalent. Superhet Principle The receiver circuits which are featured in this book are all of the superheterodyne (usually abbreviated to superhet) type, 7
Page 1 and 2: How to Build Advanced Short Wave Re
Page 3 and 4: HOW TO BUILD ADVANCED SHORT WAVE RE
Page 5: CONTENTS Page CHAPTER ONE - ADVANCE
Page 10 and 11: A block diagram which illustrates t
Page 12 and 13: It is when we come to the I.F. ampl
Page 15 and 16: This set obviously has its limitati
Page 17: The set has a frequency coverage of
Page 21 and 22: is operating at 1MHZ and has a stan
Page 23 and 24: A.G.C. Action Apart from the demodu
Page 25 and 26: ootstrapping between the output and
Page 27 and 28: Inductors T1 Denco Blue Aerial coil
Page 29: In common with many R.F. transistor
Page 32: mounting holes in the tuning drive
Page 36 and 37: The panel is then used as a templat
Page 39 and 40: B.F.O. Unit This is constructed on
Page 41 and 42: The R.F. alignment is very simple,
Page 43 and 44: CHAPTER TWO MODULAR SUPERHET In the
Page 45 and 46: distortion inevItably results in an
Page 47 and 48: odyned to a conventional 470kHZ I.F
Page 49 and 50: usual emitter bypass capacitor. VR1
Page 51 and 52: The gate terminal of Tr1 is bias by
Page 53 and 54: R2 and (2 are the source bias resis
Page 55: Mixer/Osc. Stages The mixer circuit
Page 58 and 59:
ecause more component anchor points
Page 60:
is not able to drain away the negat
Page 63 and 64:
This device requires very little in
Page 65 and 66:
Class A Circuit If the user is prim
Page 67 and 68:
and D1. C1 is an R.F. supply decoup
Page 69 and 70:
as a low value here would result in
Page 71:
With the mixer trimmer control set
Page 74 and 75:
pin 4, has a value of 960pf. When a
Page 77:
Sets of this type do have advantage
Page 80 and 81:
When this adjustment has been satis
Page 84 and 85:
Note that shortness of wiring is mo
Page 86 and 87:
Blank page 86
Page 88 and 89:
with some form of I.F. filter rathe
Page 90 and 91:
Adjustment When initially testing t
Page 92 and 93:
I.F.T.1 is a Denco I.F.T.18/465kHZ
Page 94 and 95:
switch is closed it short circuits
Page 96 and 97:
Adjustment Before switching on the
Page 98 and 99:
ut noise spikes which are very stro
Page 100 and 101:
100
Page 102 and 103:
would be necessary to have a three
Page 104 and 105:
Product Detector Although quite goo
Page 106 and 107:
Tr1 is used as a simple inductive f
Page 108 and 109:
The only adjustment which needs to
Page 110 and 111:
mica washer and plastic bush set. U
Page 112 and 113:
In use it is best to use the 1MHZ o
Page 114 and 115:
114
Page 116 and 117:
eing any gaps in the frequency cove
Page 118 and 119:
SPECIAL NOTES FOR OVERSEAS READERS
show all

How to Build Advanced Short Wave Receivers - The Listeners Guide

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?