Posted on Wednesday, October 12, 2011 • Category:
FM Transmitters
This is a simple design of a small FM Transmitter Bug that's perfect for transmitting and eavesdropping purposes. Due to the high sensitivity, even the ticking of the clock to hear. The range is estimated at anything from 50 meters. With a small piece of wire as an antenna to get at least the whole house. L1 and L2 are two equal air pools. They each consist of 5 turns at a diameter of about 4 mm. The thickness of the wire does not matter, 0.5 mm works perfectly. C4 is the frequency adjustment. Tune an FM radio in an empty area of the FM band and C4 to turn your silence or hear a whistle. From what you can precisely adjust the radio and the transmitter installed in a room somewhere to intercept. Note: Because these transmitter bugs inherently unstable, you better read the short legs of the components keep the circuit mechanically tightly together up. Also placing a 1 nF capacitor (C6) will benefit stability.
R1, R3, R4: 4K7
R2: 100K
R5: 10K
R6: 270 Ohms
C1, C2: 10 uF
C3, C6: 1 nF
C4: 2-18 pF trimmer
C5: 5.6 pF
L1, L2: air puddle windings on May 4 mm in diameter (see text)
T1, T2: 547 BC
Condenser microphone
Original Text:
Ook het plaatsen van een 1 nF condensatortje (C6) over de voedingsaanluitingen komt de werking ten goede. [Origineel TinyCAD ontwerp]
Show alternative translations
Easy FM Transmitter 5 Watts FM RF Amplifier Long Range FM Transmitter Circuit Broadcast FM Transmitter Low Pass Filter For FM 88-108 MHz USB FM Transmitter 5 Watt FM Amplifier 1W portable PLL transmitter PLL FM Transmitter using LMX1601, ATtiny2313 AT90S2313 3 Watt FM TransmitterCircuit-Zone.com © 2007-2025. All Rights Reserved.
