There are plenty of schematics out there and you may choose one or the other depending on what you actually need in terms of power. http://lmgtfy.com/?q=fm+transmitter
You must use a 38kHz crystal. That's the frequency of the multiplexer for the stereo signal. If the transmitter frequency is not that value then the receiver cannot decode the stereo signal and the sound will be monophonic.
Think about the BH1417 chip instead. It is a later generation part with better sound, and uses a 7.6 MHz crystal to digitally synthesize the carrier and directly derive the 38 KHz pilot tone. I was going to build some, then found assembled circuits on ebay for about $5 each.
If you really want to build from scratch, Mouser has the crystal for 50 cents.
2. Maybe. But "higher power"? Higher than what? Are you asking about increasing the power output of the ba 1404? If so - how much power output does the ba 1404 have? What frequency are you talking about? What is the capability of the 2n2222 at that frequency?
More questions than answers because you didn't clearly state what you really want or provide a schematic of what you have/want/propose so someone could provide a helpful answer without lots of guessing. I'm not a good guesser.
according to the spec on the ba1404, it has only 600 nanovolts coming out at 50kohm impedance. an amplifier could be built, but it would be a lot more complex than just a 2n2222.
the spec sheet I was reading was a bit fuzzier. a 2n2222 would work for this chip, you would not even need to bias the chip, since fm does not need linear amplification like am or ssb.
i constructed the circuit of ba 1404 fm transmitter and it worked. i used 32.768 Khz crystal insted of 38 Khz. the circuit worked , i didnt checked the stereo separation. but it works. another fact is that when i removed the crystal the transmitter is still working.
below is the schematics. http://www.electroschematics.com/wp-content/uploads/2009/09/ba1404-stereo-transmitter.jpg
please some one help me to design an rf amp for it to increase its range.
i saw a circuit which uses upc1675 as rf amplifier
I have merged ALL 6 threads about your FM transmitter into one thread.
You do NOT need to start a new thread for every question about the FM transmitter.
The large number of threads will only create confusion.
I am assuming because of the frequency range....this is a very low pwr amp. If this is true....you can buy very small boards with everything you need.......just attach 9 volt battery and mike.......for a couple of dollars. Search for mini fm transmitters. The older ones are discrete and you can experiment with them. The newer ones are just one IC.