Spy Bug Fm Transmitter

Spy Bug Fm Transmitter

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This fm wireless transmitter should only be used for educational purposes.

Regular transmission using such a transmitter without a licence is illegal.

I would like to tell you not to use this for illegal things

This transmitter can deliver signals up to 50 meters. The transistor 2N2222 serves as the modulator 

as well as oscillator. Capacitor 33pf and inductor L1 forms the necessary tank circuit for making 

oscillation. Adjustments in the transmission frequency can be made by compressing or relaxing

the coil. The voice to be transmitted is coupled to the base of Q1 using an electret microphone. 

The FM signal available at the collector of Q1 is radiated using the antenna.

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Notes.

    Use a 3V battery for powering the circuit.

    The circuit can be assembled on a Vero board.

    Coil L1 can be made by making 5 turns of 24AWG wire on a 1cm plastic former.

    Antenna can be a 25cm long 18AWG wire.

FM transmitter 800m (2400ft)

FM transmitter 800m (2400ft) 

This fm wireless transmitter should only be used for educational purposes.

Regular transmission using such a transmitter without a licence is illegal in most countries.

I would like to tell you not to use this for illegal things

This is one of the smallest and neatest FM transmitters to be presented as a construction project

This will save going to a number of suppliers as no single supplier has all the 

necessary components. 

FM transmission is the best mode for transmitting a signal as it does not suffer 

from interference such as electrical noise from car engines or electrical appliances

etc. It also achieves the greatest range with the least power.

With just a handful of components and a few milliwatts of output power you can 

produce an FM transmitter with a very impressive range and perfect clarity.

With a 175cm (5ft 9in) (half-wave antenna) the range has been 

conservatively rated as 800 meters (2400ft) under normal working conditions. In many 

countries you must reduce the maximum range to 30ft (10 meters) by cutting the antenna

to 10 inches. If this is the case, you must abide by it. Some countries totally ban

these brilliant devices. You need to find out the situation in your own locality.

Using a battery for powering the circuit will reduce noise. 

For More Details Visit 

http://www.talkingelectronics.com/projects/Voyager/Voyager-P1.html

PARTS LIST

SEMICONDUCTORS

2 - 2N2222   (NPN transistors)      Click Here to view Datasheet

RESISTORS

1 - 470R  

1 - 10k    

1 - 47k   

1 - 68k   

1 - 1M    

CAPACITORS

1 - 10p ceramic-disc 

1 - 39p ceramic-disc 

1 - 1n ceramic-disc 

2 - 22n ceramic-disc

1 - 100n 

1 - 5p to 30p air trimmer

ADDITIONAL PARTS AND MATERIALS

1 - 5 turn coil 0.020inch (0.5mm) enamelled wire 1/8in (3mm) diameter

1 - electric microphone

1 - 9v battery 

1 - 9v battery snap

12in (30cm) fine solder

5ft 9in (175cm) hook-up wire.

SUMMARY OF SPECIFICATIONS

Supply:- 9 volts
Current consumption:- 7mA
Tuning range:- 80 - 110MHz (by stretching or compression the oscillator coil)
Fine tune by adjusting the air trimmer (2MHz adjustment)
Stability:- Low. Bug to be left in-place and not to be moved or handled.
Antenna length - 175cm (5ft 9in)