FM microphone made by 9018

This wireless microphone has a reasonable circuit design, beautiful shape, long sound transmission distance, long service life, economical and practical, low power consumption, and is suitable for use in ordinary FM radios.

Production of oscillation coil L: Wind 4T of Ф0.5mm enameled wire on a Ф5mm straight shank drill bit.

Adjustment of oscillation coil L: Turn on the radio (set to FM) and microphone switch, then hold the microphone, speak into the microphone and adjust the station knob until your voice comes out of the radio. If you still can't hear your voice in the entire frequency band (i.e. 88~108MHz), carefully adjust the oscillation coil L. When adjusting, just open or reduce the distance between each turn of the coil. Be careful when adjusting. If adjusting the tightness of the coil still has no effect, solder L off to increase or reduce one turn (due to the influence of electronic component parameters), and then re-solder it and continue the above adjustment.

Before preparing for installation and production, please use a multimeter to screen the quality of each component. If conditions permit, measure the capacitance of each ceramic capacitor. This will ensure that everything is safe and the installation will be successful. When welding, the quality must be guaranteed, and there must be no false welding, false welding, or wrong welding.