Simple and powerful FM TRANSMITTER
this is a simple but quite powerful fm transmitter having 3 amplifier stages, i constructed this circuit about one year ago with great results! And I still use it for many purposes. this circuit is not designed by me it is designed by sir collin mitchel from australia so all the credits and thanks go to him.
this transmitter “broadcasts” FM signals on 88-108 mhz fm band and can recieved the transmitted signal using any ordinary fm radio within the range of 200 meters! But in open area this simple transmitter can reach about 1KM far with great stability!, i seriously recommend you this transmitter if you are new into the amazing world of radio broadcasting!.
Build this circuit neatly on a general purpose PCB and always double check the connections and every joints of the circuit before you power up. The inductors should be made on a refill of an ordinary pen and turn 6 turns with a copper wire with enough thickness, and solder the inductor next to the variable capacitor. You may replace all the transistors with bc547,549,pn2222a etc but i prefer 2n3904 as it is good for RF,
● i used a mobilephone battery(3.7v nokia bl-5c) to power this circuit that way i don’t need buy a battery in every week.
● you can attach a charger slot in the battery to recharge it using a nokia charger when the battery is low
● you might need to reduce the value of biasing resistors of the transistors (try 100K or 120K)
as these batteries can provide only 3.7V
● always follow the specified rules while handling the battery
● you are not allowed to use this transmitter against any person
● it is illegal to use a transmitter without a license, so always follow the rules