If you are an average hobbyist, the UHF transmitter deisgn is not the job for you. Regarding costs, it depend on the design, and for the design, you may google it. Cheers
Questions:
1. digital or analog modulations
2. pre bulit blocks (funcion ICs) or
3. you want to build it from the bottom part-by-part
4. is it okay to involve a PC into the comm link? (Software Defined Radio, less hardware)
5. What is your range requiment?
Anyway if you choose an irregular freq for your comm chanel noone will listen you...
Added after 11 minutes:
maybe this is what you need:
**broken link removed**
i just want to build a wireless microphone that no one can listen to it, but me...and i thought that the best option is UHF Transmitter...i dont know what to do...
As already mentioned, UHF designs are a bit complicated in respect of frequesncy stability and other RF design principles to be followed. You may follow the links given in this thread, construct a FM Tx and tune it out of the FM band may be on 76Mhz or on 110Mhz and tune the receiver to the same frequency. May be this is the easiest what you can do for privacy...Cheers