555 Oscillator Circuit

First, I think that you should know, designing an FM transmitter from scratch is a very ambitious project.

While one certainly can use a 555 oscillator for part of an FM transmitter, I don't believe it can be the sole or even primary active circuitry. (Unless somebody else here can cite a 555 application note.) To reduce the design complexity you could utilize an off the shelf FM modulator chip, many exist for different frequency ranges.

This brings up the critical questions that must be answered and what they will affect in your design:

• At what frequency will you be broadcasting?
• Defines antenna options
• FCC or other administration compliance with frequency selection
• What modulation technique?
• Analog
• Digital
• QPSK
• FSK
• Distance of broadcast?
• Output power level
• How will this signal be received?

prady, I realize that you wished for an answer to your question instead of more questions, but without more information a good answer cannot be formed.