Would you like to create your own radio station, send music around the house, or just make a wireless link between your iPod and the receiver in your car, this transmitter will let you do these things easily. With BA1404 HI-FI Stereo transmitter you will be able to send MP3 music from your iPod, computer, discman, walkman, TV / SAT receiver, and many audio sources other. This FM transmitter in the design is the result of many hours of testing and tweaking. The goal is simple, to test many BA1404 transmitter design that is, comparing their performance, identify weaknesses and come up with new BA1404 transmitter design that enhances sound quality, has a frequency stability is very good, maximizes transmitter’s range, and easy enough for everyone to build. We are pleased to announce that the goals and expectations have been met and even exceeded. The following is a schematic drawing:

Transmitter can work from a single 1.5V battery cell is very good and gives a clear stereo sound. Can also be supplied from two 1.5V battery cells to provide maximum coverage. Secret Behind Sound Quality and Frequency Stability. One of the BA1404 quality FM transmitter is the frequency stability is excellent. This is mainly due to the use of high-quality 3.5 turn variable coil. RF coils are ideal for melodic precise frequency tuning for a magnetic wire half embedded in the plastic, which minimizes frequency drift. Ordinary air coils are not preferred for professional broadcasting because the coil expands and contracts with temperature changes. That is the reason why the variable chosen as a replacement coil to coil and variable air capacitor.

Another quality that served BA1404 transmitter is crystal clear stereo sound and enhanced sound separation. There are several factors that account for increased sound quality and separation. The first reason is the use of crystals that provide 38 KHz frequency solid stereo encoder. Another reason is the use of two 1nF decoupling capacitor for the BA1404 chip one and one for the variable coil 3.5. These capacitors should be as close as possible to the BA1404 chip and a coil variable as this will greatly improve sound quality, sound and even the frequency separation of stability as well. What they do is filter out the noise in the incoming DC voltage. If the chip enters BA1404 stereo sound generator will enter a voice in influencing both sound and transmitted multiplex signal which is responsible for the generation of a clear stereo signal. If the sound it makes will also be included in the subcarrier frequency generation affects the frequency stability. Most people do not realize how important this is and perhaps put them in the wrong location, far from the target which provides the components useless, or worse, decide not to use these capacitors at all.

Another factor that is very important and that improving the overall quality of the overall frequency transmitter BA1404 including stability, sound quality and sound separation is the use of ground planes transmitter’s PCB. It is recommended that a plane lands should always be used in the circuit associated with a higher frequency.

Section:
L1 – 3.5 It Variable Coil
IC BA1404
38KHz Crystal
ANT – 30 cm of copper wire

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