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Return to BlogHigh Power FM Wireless Microphone
Posted Jan 21, 2012 at 10:59 am
Figure 1
This one is a high power FM wireless microphone that provides very good frequency stability in about 1km range and very good microphone sensitivity. It can be used inside guitars, as a part of remote control systems or in other similar applications.
The features said above are achieved by including an RF amplifier stage with 10dB gain and AF preamplifier stage to boost the modulation.
The circuit construction is simple. L1 is integrated into the PCB with 3.25 turns. Transistors are not critical. The BC547s can be replaced with any small signal NPN type transistor and BC557 is a general purpose PNP transistor so it can also be replaced easily.
The power consumption is low. The finished circuit draws about 30mA. A single 9V battery is ample to power the FM wireless microphone.
The PCB file is given in the download section of the project page. You should check Harry’s page for more detailed information about the components, PCB modifications and the other features of the circuit.
Read More: web.telia.com/~u85920178/right_01.htm
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3 years ago: Hi, what is the wireless range before the signal degrades?
2 years ago: what is the maximum range of this microphone before it will fade the input audio?
2 years ago: this could last a very long time when in use because the current consumption is just low..