Re: can I change the output frequency of my fm transmitter?

[nxt02]

u can change the antenna windings by amount size and you can also change the thickness of the wire used. or add a variable capacitor across the antenna. hope that helps  :-\

 

[audioguru2]

Adding a variable capacitor across the antenna will not change the frequency.
The circuit probably uses a modern frequency synthesizer circuit with a quartz crystal and phase-locked-loop. Maybe the crystal can be replaced with one having a higher frequency. The existing crystal might be 6.2MHz. Try a 7.6MHz crystal.