how to determine frequency of BA1404 stereo FM transmitter?

[ymmen]

how to determine frequency of BA1404 stereo FM transmitter?
i used the circuit given in link provided below
https://electronics-diy.com/BA1404_Stereo_FM_Transmitter.php

 

[jiripolivka]

how to determine frequency of BA1404 stereo FM transmitter?
i used the circuit given in link provided below
https://electronics-diy.com/BA1404_Stereo_FM_Transmitter.php

This transmitter can be adjusted over the FM band, 88 -108 MHz, by tuning the RF coil by using a plastic screwdriver or a toothpick fitting to the ferrite core.

The usual procedure is to use a FM receiver with a connected antenna, find an "empty" channel without a program, then switch on the transmitter with an audio input active, and tune it to that channel.

As the transmitter is mounted on an open PC board, moving your hand close to it will affect the frequency. After you try the above function, I would recommend to build the PCB into a metal box with a DC feedthrough and antenna output connector and audio input connector. Leave a small opening to access the coil to tune the transmitter. Such configuration will stabilize the frequency and makes sure it can work well.

 

[D.A.(Tony)Stewart]

Usually these ferrite cores are slotted so a long plastic tip thin blade screw driver is used for tuning. The ferrite is very brittle, so it must never be forced. Any metal tip affects the coil while tuning.

 

[udhay_cit]

Can you find all the component required for this FM transmitter? I'm using BK1085, Chinese IC.