Solid State Shortwave Receivers For Beginners - The Listeners Guide

level that reaches the detector of the receiver, and so elliminate the overloading.
The less tight coupling of the aerial to the tuned circuit increases
the selectivity of the receiver slightly, and this also helps to remove the
overloading.
Cases
If the constructor wishes to house any of the receivers described
here in an outer casing, it is an easy matter to construct a case from
plywood using ordinary glued butt joints. Self adhesive plastic material
can be used to cover the completed case, and should provide a very
attractive finish.
One point must be borne in mind however. Unless the receivel
is to be used on only one range, the lid of the cabinet must be easy to
remove in order to facilitate coil changing. Another popular method
is to use a hinged lid, or to have a hinged compartment in the lid
above the coilholder.
Construction Hints
Fairly detailed constructional information has been provided for
these first two receivers, and this should give the reader a good general
idea of the methods used when building simple S.W. sets. The circuits
shown in the remaining part of this book will be discussed in comparatively
broad terms and constructional information will not be provided.
Provided a few points are kept in mind, little difficulty should
arise when translating a circuit diagram into a practical design.
It is important that all wiring that carries R.F. should be kept as
short and direct as possible. This is particularly important in the case
of R.F. decoupling capacitors. For this reason it is advisable to use
point to point wiring in the R.F. and detector circuitry.
Avoid having R.F. chokes, tuning coils, and even speaker coils
very close to one another. Feedback between two closely spaced coils
can upset the operation of the circuit.
Wiring of the audio circuitry of a receiver is not usually too
critical, and Veroboard, plain matrix boards, tagstrips, etc. are suitable
for use here. However, try to keep input and output leads well away
from one another, particularly where two stages of audio amplification
are used. It is also a good idea to keep the wiring at the input of the
audio stages as short as possible so that there is a minimum of stray
pick-up of mains hum, and similar A.F. interference.
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