Function This item make the sound around the microphone into the FM radio and transmit out to achieve pickup and wireless radio FM transmitter the launch frequency is adjustable the core board green components is the adjustable capacitor change the adjustable capacitor can change Launch frequency adjustable range covering 88 108MHZ GB FM band You can use the radio and the phone the phone with the headset line to do the antenna sensitivity is poor is not recommended as a receiver as a receiver It is widely used in voice pickup transmission audio MIC the elderly and children sleep monitoring etc need to pick up the sound of the occasion Features This item has unparalleled wide voltage working range from 0 7V to 9V It launch pure spurious signal the suppression is only 60dBc Parameter Operating voltage 0 7V 9VFrequency regulation range 88 108MHZ default 100MHz Launch distance 9V work the use of 70 cm antenna open space launch distance of 50 100 metersThe relationship between the operating voltage volts and the supply current MA and the transmitted power dBm is as follows 9V 24 Ma 10 2dBm i e 11 MW 8V 21 Ma 9 5dBm7V 19 Ma 8 5dBm6V 17 Ma 7 1dBm5V 14 Ma 6 1dBm about 5 MW 4V 12 Ma 4 5dBm3V 9 Ma 2 2dBm2V 6 Ma 1dBm about 1 MW 1 5V 4 2 Ma 4dBm about 0 5 MW general home environment emission enough green radiation small 1V 2 4 Ma 9dBm0 7V 0 9 Ma 20dBm i e 0 01 MW Wiring method The back of the core panel is labeled