This FM Wireless Microphone Surveillance Transmitter is the latest micro-chip FM transmitter module. It has a built-in microphone and adjustable frequency Potentiometer.
Description:
The FM Wireless Microphone Surveillance Transmitter Module is compact and easy to fit into thick pen barrels and lighters. The module emits a fairly stable frequency that can be received using any radio, especially with a digital radio. But buyers need to solder the power supply and antennas themselves.
Principle: The module local oscillator circuit adopts the local oscillator circuit form of the black-and-white TV tuner. The frequency is super stable. It is not the ordinary capacitor three-point oscillation circuit. The module is added to the amplification isolation circuit, and the LC filter circuit and impedance matching are used. The circuit effectively filters out the second harmonic and the third harmonic. The spectrum is very clean. I tested this circuit to 200MHZ. Even if the antenna of the module is caught, there will be no frequency drift. The RF output impedance of the module is The 50 ohm convenient module is directly matched with the power amplifier, which is more suitable for the user's DIY needs!
Principle: The module local oscillator circuit adopts the local oscillator circuit form of the black-and-white TV tuner. The frequency is super stable. It is not the ordinary capacitor three-point oscillation circuit. The module is added to the amplification isolation circuit, and the LC filter circuit and impedance matching are used. The circuit effectively filters out the second harmonic and the third harmonic. The spectrum is very clean. I tested this circuit to 200MHZ. Even if the antenna of the module is caught, there will be no frequency drift. The RF output impedance of the module is The 50 ohm convenient module is directly matched with the power amplifier, which is more suitable for the user's DIY needs!
How to Make Fm Transmitter Bug:
- Take Your FM transmitter microphone circuit and hook up a 3.7 volt battery at its positive and negative terminals.
- Cheap alternative to the lipo battery you can use Two 1.5v Button cells in series.
- Middle terminal of this board is your antenna now without antenna its range is very limited. There is no antenna that is Ultra small and still do the job of increasing the range. You can also make an antenna by yourself.
- You can use a conductive copper foil tape which can be sticked on to the back side of the battery in plus shaped and after that solder to the middle terminal of FM transmitter board. Your FM transmitter is ready now.
How to Brodcast Your Voice on FM:
- If you follwed each step perfectly your voice should be already transmitting onto FM frequencies.
- To find frequency on to which Your FM transmitter is transmitting on you can use any kind of a FM receiver. You can also use your smartphone since it can also record your audio.
- Now use auto scan feature and scan thorugh channels and eventually you'll find your own voice coming through FM receiver.
- Also you can do this opposite way you can adjust the frequency on to your FM transmitter bug you need to use a small trimmer Potentiometer screwdriver and gently turn the Potentiometer in anticlockwise way don't force too hard or it might break.
Stable performance: When the module supply voltage is 3V, the emission distance is about 100 meters in an open environment. In a typical indoor environment, the distance is about 20 meters. The higher the voltage, the farther the emission distance is. At 9V, the emission distance can reach 300. Around the meter, the antenna can be used with a whip antenna, a common wire or a rough enameled wire, and the whip antenna and the rough enameled wire have better effects. The length of the antenna is about 75 cm and must be straightened when in use. Of course, the short antenna can also shorten the transmission distance. The transmission distance is only for reference.
Specifications:
- Operating Voltage: DC 2V- 9V
- Current: 9mA (3V voltage
- Operating frequency: 85MHZ ,--- 1 1 5MHZ (usually between 99 101boot default frequency)
- Receive way: as long as the 88- 108MHz F M radio can receive, withF M feature phones.
- Frequency adjustment: adjustable capacitor
- Output Impedance: 50 ohms
- Size:2 cm * 1cm L*W
- FM transmitter Range is about 100 metres in open ground, about ~10 to 30 metres it depends on the size of antenna small copper foil antenna will get you 10 meters and if a person is holding this FM transmitter whole persons body act as an antenna and you can get up to ~20 metres of range. Good dedicated antenna will give you up to ~30 metres.
- Sensitivity: The microphone is placed in a quiet 30 square meter room, and the sound of the quartz clock second hand is clear and audible.
- Scope of application: high sensitivity wireless microphone, wireless recording, wireless monitoring, remote recording, maternal and child care, patient care, etc. Because the sensitivity is too high, it is not suitable for stage performance, and it is easy to produce howling. Do not use it for illegal eavesdropping! The consequences are at your own risk!
- Working time: The working time of the module is determined by the battery capacity. The specific time is divided by the battery capacity divided by the module operating current.
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