coll circuit

For those of you like / love to talk in the air can assemble this simple circuit that can be received by the radio receiver to within a few hundred feet. The voice that issues by this circuit at all clear without rustling. Can also be used to link communications over the air using this radio transmitter, provided that other person also had the same circuit.

This PCB design :


Description :

Resistor
R1__________________1K
R2__________________18K
R3__________________82K
R4__________________1K2
R5__________________5K6
R6__________________39K
R7__________________18K
R8__________________68K
R9__________________470R
R10_________________100R
R11_________________50K

XTal
Q1__________________ Crystal according to the desired frequency

Inductor
L1__________________10uH


Capacitor
C1__________________10uF
C2__________________30uF
C3__________________20uF
C4__________________47uF

Transistor
Tr1_________________2SB175
Tr2_________________2SB175
Tr3_________________2SB178

Antenna
X1-1________________10-20 meters

Connector
X2-1________________Ground
X2-2________________VCC 9-12 Volts DC
X3-1________________Input
X3-2________________Ground