Solid State Shortwave Receivers For Beginners - The Listeners Guide

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.
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