Page 85 - Build Your Own Transistor Radios a Hobbyists Guide to High-Performance and Low-Powered Radio Circuits

RF Ant. Filter Multi-Stage Amplifier Det
VC&T1 01 to 06 07
Loop Antenna

R13 C6
AFOut
47K '~
2 06
C5 330K
~~4126 ~
R12
0.0033 ut
R7 47K
20K
Low Side
Tap

FIGURE 5-4 Block diagram and schematic of a previous TRF radio design
with a loop antenna.

RF Ant. Filter Multi-Stage Am plifier Power Det
VC &L1 Q1 to Q3 04

+3
C7
~
0.01 uf

AF Out
.2 I
loc:033~

C4
1 DO uf

+ 3

R1
lOOK

01
1N914
02
1N914
FIGURE 5-5 TRF radio with differential pair transistors to reduce
unwanted oscillations.