Urgent help for a transmitter

[aimans]

i m tryin to construct a telephone fm transmitter which connects to the phone line in series. i have used two schematics from the internet but both fail to work, i dont know what is the problem. all the soldeing and circuiting is fine. but is it because of the inductor wire? cause i am using a 0.75mm thick wire[about 21 gauge], i also tried the capaciter trimmer for my second circuit but i heard nothing on the radio, all the components are exact, except for the transistors which i replaced with ones with similar characteristics.

please anyone out there, help me,

 

[audioguru2]

You changed the transistors but you forgot to tell us which ones you used.
You forgot to show your pcb so we can see if the wiring is short enough for 100MHz.
At 100MHz, a wire is an inductor. If the wire is longer than about 3mm then the inductance is too high.
Wires side-by-side have capacitance between them If the wires are high impedance and are side-by-side for more than 3mm then the capacitance is too high.

Don't use a breadboard for 100MHz circuits.
This FM transmitter had its parts so far apart that the wires between them had too much inductance. It didn't work:

View attachment 40348

 

[aimans]

for the second circuit, i replaced 2N3904 with KN2222, and 2N3906 with MPS2907A.

 

[aimans]

i did not use a breadboard, i made a PCB from a copper sheet, it measures 3cm x 4cm, the parts are close enough and most of the wires short. but still it is not working. i just dont get it.

 

[audioguru2]

Hi Almans,
Both your schematics don't show any parts values so we don't know if they will or ill not work.

The 2N3906 looks odd and the coil L1 is missing a tuning capacitor in your second circuit.