FM Transmitter: Where's the problem?

I have a schematic and pic of my FM transmitter in this other post:

Thanks, audio I'll give that one a try. What is the requirement for the I/P connection? Can I connect a mic here without the preamp shown at the bottom of the webpage? Also how important is the capacitor type? If there any preferred types besides 'disc?'

Hi DigiTan,
My schematics all show where its elecret mic connects to its preamp that has gain and pre-emphasis. I used a transistor for the preamp that works fine, but someone else posted a preamp using an opamp that also works fine.

If you don't use my circuit's built-in preamp with pre-emphasis, you will have to eat the mic because the mic's output level is low, and it will sound like crap without pre-emphasis because all FM radios have a matching de-emphasis that cuts the boosted treble back down to normal (at the same time cutting hiss). Without having pre-emphasis in the transmitter, its received sound will have its treble cut way down by a radio's de-emphasis.

The FM broadcast band is VHF and is around 100MHz. Most capacitor types except ceramic discs are an inductor at these very high frequencies, the opposite to what is needed. I have used newer tiny "monolythic ceramic" capacitors instead of older ceramic disc ones with success in FM transmitter circuits as shown in my pic as the tiny yellow 470pF one at the bottom.