FM Wireless 3VDC

[16F877A]

i plan to build it just for fun , but i dont know workable o not . so i need some one to help me see this circuit thank you very much ^^
**broken link removed**

 

[audioguru]

It will probably work if it is built on a small pcb with the parts close together BUT:
1) Its frequency will change if something gets close to the antenna or moves away because the capacitance of the antenna will change and it is connected directly to the tuning LC circuit.
2) Its frequency will change as the battery voltage runs down because the capacitance of the transistor changes when its supply voltage changes and it is connected directly to the tuning LC circuit.
3) It will sound muffled without treble audio frequencies because it doesn't have pre-emphasis (treble boost) like FM radio stations have and the de-emphasis in all FM radios will cut the high audio frequencies.

It is a very simple old circuit. I made it about 48 years ago.

 

[16F877A]

It will probably work if it is built on a small pcb with the parts close together BUT:
1) Its frequency will change if something gets close to the antenna or moves away because the capacitance of the antenna will change and it is connected directly to the tuning LC circuit.
2) Its frequency will change as the battery voltage runs down because the capacitance of the transistor changes when its supply voltage changes and it is connected directly to the tuning LC circuit.
3) It will sound muffled without treble audio frequencies because it doesn't have pre-emphasis (treble boost) like FM radio stations have and the de-emphasis in all FM radios will cut the high audio frequencies.

It is a very simple old circuit. I made it about 48 years ago.

thank u sir ^^.
you really help me alot . no matter how old of this circuit , i m sure i will learn something in this antique(circuit) . i m going to build it

 

[shokjok]

This should work down to 3V if you use an SMT transistor and a fingernail-sized PC board.

 

[رابح54]

3 v dc fm transmitter

you must to replace the 10k resistor wiht 33k - 39k - or 47k , and you connect a 10pf , 15pf or 22pf condenser betwin antenna and collector