If you want to transmit the music around the house then you can make your own small radio station by making project using this circuit . Make your own radio station with this circuit, and transmit the music around the house. You can transmitt with the connecting of your mobile phone or another audio device and simply create a wireless link with you and a receiver in your area . The implementation of this circuit easy. With BA1404 HI-FI Stereo transmitter you will be able to transmit MP3 music from your mp3 player, computer, TV / SAT receiver, and many other audio sources. In this ckt mic not use but directly audio input connects with audio jack.
The Ba1404 ic is good quality digital Fm transmitter . BA1404 transmitter design that improves sound quality, has very good frequency stability, maximizes transmitter's range, and is fairly simple for everyone to build. We are happy to announce that this goal and expectations have been met and even exceeded.
The transmitter can work from a single 1.5V cell battery and provide excellent crystal clear stereo sound. It can also be supplied from two 1.5V battery cells to provide the maximum range.
One of the qualities of BA1404 FM transmitter is excellent frequency stability. This is mainly due to a use of high quality 3.5 turn variable coil.
There are several factors that account for improved sound quality and a separation. First reason is the use of 38 KHz crystal which provides rock solid frequency for stereo encoder. Another quality of the BA1404 transmitter is a crystal clear stereo sound and improved sound separation. . Another reason is the use of two 1nF decoupling capacitors one for BA1404 chip and another for 3.5 variable coil. These capacitors have to be as close as possible to a BA1404 chip and a variable coil because this will GREATLY improve the sound quality, sound separation and even frequency stability as well. What they do is filter out the noise in the incoming DC voltage. If the noise enters BA1404 chip stereo generator will include it in a transmitted sound affecting both the sound and multiplex signal that is responsible for generation of the clear stereo signal. If that noise enters it will also be included in a generation of subcarrier frequency affecting the frequency stability.
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For optimum transmission range the length of the antenna should be 1/4 or 1/2 of the wave length of the transmitted frequency. Use this simplified formula to determine the antenna length for 1/4 wave length antenna type: (30000 / Transmitted Frequency) / 4 = Antenna Length (in cm)
(30000 / 108MHz) / 4 = 70cm Antenna
Cristal 38khz 1
IC= BA 1404
L = enameled coil of copper 3 turn of 5 mm round