Sunday, January 24, 2010

fm radio transmitter

FM Transmitter
Here is the schematic, PC board pattern, and parts placement for a low powered FM transmitter. The range of the transmitter when running at 9V is about 300 feet. Running it from 12V increases the range to about 400 feet. This transmitter should not be used as a room or telephone bug.

Digital FM Transmitter
The FM Transmitter uses FM radio waves to send sound from any device you choose to any nearby radio or stereo system. The only wire you have to connect is from the FM Transmitter to the headphone jack. Simple as that. And since the Transmitter works with any device that has a headphone jack, you can use it with your computer, WiFi radio, MP3 player, DVD player, and even satellite radio. One of the unsung qualities of C. Crane’s Digital FM Transmitter is its extreme versatility. While most people use it to send music from their computers or MP3 players to a nearby radio, some customers have told us how they use it with their guitars, portable DVD players (a lot of fun in cars), and even other radios. It is perhaps the only FM Transmitter with adjustable audio input so it can handle virtually any level of audio input.

Low Power FM Transmitter
This article should satisfy those who might want to build a low power FM transmitter. It is designed to use an input from another sound source (such as a guitar or microphone), and transmits on the commercial FM band - it is actually quite powerful, so make sure that you don't use it to transmit anything sensitive - it could easily be picked up from several hundred metres away.

FM Transmitter Circuit
An low power FM Transmitter using an op-amp as the audio preamp and a single transistor as the RF amplifier.

This is an improved kit 18. At first sight it looks similar to the original Kit 18 – especially the inductor
etched onto the PCB – but it has been tinkered with by Harry Lythall in Sweden to give the best distance and stability for its size.

FM Radio Transmitters
The Si471x is the industry's first 100% CMOS, single-chip FM transmitter IC. The Si4712/13 are the industry's first integrated transmitters with Receive Power Scan (RPS).

BA1404 HI-FI Stereo FM Transmitter Kit
 Be "On Air" with your own radio station! BA1404 based transmitter is an exciting product that will broadcast high quality stereo signal in 88MHz - 108MHz FM band. It can be connected to any type of stereo audio source such as iPod, Computer, Laptop, CD Player, Walkman, Television, Satellite Receiver, Tape Deck or other stereo system to transmit stereo sound with excellent clarity throughout your home, office, yard or camp ground.

BA1404 - HI-FI Stereo FM Transmitter Project
 This high quality stereo FM transmitter prototype is a result of many hours of testing and tweaking. The goal was simple; to test many existing BA1404 transmitter designs, compare their performance, identify weaknesses and come up with a new 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.

BH1417 Stereo PLL FM Transmitter

This is the latest BH1417 FM Transmitter design from RHOM that includes a lot of features in one small package. It comes with pre-emphasis, limiter so that the music can be transmitted at the same audio level, stereo encoder for stereo transmission, low pass filter that blocks any audio signals above 15KHz to prevent any RF interference, PLL circuit that provides rock solid frequency transmission which means no more frequency drift, FM oscillator and RF output buffer.

BA1404 Stereo FM Transmitter IC in stock
 As of today we are starting the sale of the popular BA1404 IC which has integrated stereo encoder and FM transmitter, all in one package. We also carry 38KHz crystals so if you have been waiting to build your own stereo FM transmitter to transmit your music around the house, grab a schematic from the "Schematics" section and start building one today.

Long-range FM Transmitter
The circuit built around transistor T1 (BF494) is a basic low-power variable-frequency VHF oscillator. A varicap diode circuit is included to change the frequency of the transmitter and to provide frequency modulation by audio signals. The output of the oscillator is about 50 milliwatts. Transistor T2 (2N3866) forms a VHF-class A power amplifier. It boosts the oscillator signals’ power four to five times. Thus, 200-250 milliwatts of power is generated at the collector of transistor T2.

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