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Hello friends,

This an easy FM transmitter made with the PCB of a toy walkie talkie . It is easy to build and all you have to need is a walkie talkie having FM bandwidth.Here, i have hacked the walkie talkie's frequency to my own frequency . It's frequency is manually set to 102.5. 

REQUIREMENTS

1 . A walkie talkie of FM band 
2 . A LED (to be used as the power indicator)
3 . Microphone 
4 . Some wires

NOTE: LED and microphone is usually available with in the walkie talkie 


PUTTING ALL TOGETHER

1 . Open the walkie talkie an take out the PCB , LED , speaker and microphone

2 . cut of the wires to speakers (as FM transmitter does not need speaker to do something)

3 . Adjust the inductor L3 so as to manipulate the frequency (The frequency must be adjusted manually with trial and error                    method using a FM receiver . DO NOTE THAT IT DOES NOT INTERFERE WITH ANY OTHER FREQUENCY)

4 . Place the circuit in a suitable case and fix it firmly

5 . Connect the LED and microphone (if not connected)

6 . Supply an appropriate power to the circuit ( In this case it is 3V DC)

EXTENDING THE FREQUENCY

In order to increase the range of transmitting connect a telescopic antenna to the antenna outlet
(If needed you can amplify it using another electronic circuit)

IMPORTANT !!!

The frequency that you assign to the FM must satisfy with the respective broadcasting rules prevailing in the country.
It should not cause any interference to other signals

The maximum range of the transmitter depends upon the circuit that is used 

<p>hello anandakrishnan</p>
<p>Hello binoy bastin</p>
<p>can u use a old fm radio to do this ?</p>
<p>i was in search of a trimmer capacitor and coudn't guess what this part is..can u tell me what this is....</p>
<p>its a variable inductor</p>
Please tell me which part exactly :)
<p>From the circuit I think you should adjust the L1 if its the trimmer inductor.</p>
Please tell me what is the part i should adjuat to manipulate the frequency
<p>you should adjust the trimmer inductor</p>
<p>Can 0you a link a walkie talki set to the private frequency. With 100 percent confidence that it wont be picked up by police or truckers?</p>
<p>radio frequencies are harder to trace. But even though they can be spotted, but these walkie talkies wont have much range.</p>
<p>i was in search of a trimmer capacitor and coudn't guess what this part is..can u tell me what this is....</p>
What model radio/ walkie talkie did you use?
<p>I used a FM band walkie talkie which are cheap and are easily available.</p>
<p>This is incredible! A custom channel? Extend the range and you've basically built a cell phone, no?</p>

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