Working voltage: DC 2V-9V (A type) (It is recommended to use battery power. The regulated power supply will have hum, and the voltage rise frequency will change slightly, but the long-term operating frequency will not change under the same battery.)
Working current: 9-15mA (3V voltage test, super power saving, voltage increase -> current increase -> power increase -> distance further)
Emission distance: 100 meters in open area (3v voltage test), the distance between indoor walls and walls decreases, and the distance between reinforced concrete walls decreases significantly. Increasing the voltage can greatly increase the distance.
Operating frequency: 85MHz -115MHz (the default factory frequency is generally between 99.0-100.9 MHz)
Receiving method: Normal FM radio can be received, and FM-enabled mobile phones are also available.
Frequency adjustment: miniature adjustable capacitor on the board, you can adjust the frequency with a small screwdriver
Output impedance: 50 ohms
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.
Excellent quality: This module is the latest micro-chip FM transmitter module, which is made by better PCB technology. It 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.
The principle is simple: 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!
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.
Size: 20mm x 10mm （L*W)
1 x 88-108MHz FM Transmitter Wireless Microphone Surveillance Spy Bug Board Module 2V-9V
Instructions are NOT included. We don't provide technical assistance please make sure that you are familiar with the product before purchasing.