For the install steps, please check below:
2.Operating Current: 5-15mA
3.Operating Voltage: DC 3-6V
4.Transmission Distance: 5-50m
5.Transmission Frequency: 88-108MHz
6.Audio Input: -15dB (max)
7.PCB Size: 53*40mm
FM transmitter for self assembly. For some reason, the seller positions his kit as a radio microphone, although the range of application of the assembled device is much wider – from an elementary radio extension to a jammer of a radio chanson loved by marshalling machines. The lot includes everything you need for assembly. Not only the circuit, but who did it stop when? ??
The printed circuit board is made efficiently, the contact pads are well-deserved, the designations of the elements are easy to read, both numbers according to a nonexistent scheme and ratings are indicated, which allows you to collect everything without additional pieces of paper. When assembling, it must be borne in mind that the coils are marked by the number of turns, and the spelling 1 and 4 in the marking of the capacitors on the board are very similar.
?Surprisingly, the assembled circuit began to work immediately, without additional dances with a tambourine. The power was organized by a lithium battery, a 4v and 50cm piece of wire instead of an antenna was enough for stable reception at a distance of 15m behind two brick walls. To increase the range, you can raise the supply voltage to 6v and screw the whip antenna. It is unlikely that it will be possible to use a karaoke radio microphone due to large noise and lack of shielding. For espionage purposes, the transmission quality is sufficient, but the microphone sensitivity is very mediocre. How does the fm jammer work when shorting the microphone with a low-impedance resistor and so infuriates the minibuses, so for this purpose the toy may not be safe??
In general, the penny price and ease of assembly outweigh the shortcomings in the form of a lack of circuitry and microphone noise. By the way, from a linear input, sound is broadcast with a quality comparable to a radio station, but only in mono version does not cause any complaints. It can be used as an option for connecting wireless headphones with a built-in FM receiver to the TV, if you want to watch, but the sound disturbs the neighbors in the house.