Making a 49 mhz radio transmitter

I had a toy helicopter that was controlled by a radio remote, and the helicopter broke. So I open up the remote and extract the oscillator and the actual telescoping antenna. Does anybody know where to start to make a radio transmitter that can interface with arduino?

Even if we could tell you exactly how to do it you would need certain equipment, like a spectrum analyzer and a scope. I won't say it is impossible but if you are asking that question then it might as well be. Buy a radio on ebay. It would save you a lot of trouble.

Does anybody know where to start to make a radio transmitter that can interface with arduino?

That would depend on just what you expect the transmitter to do.

the toy uses PPM ,, this is decoded factory default ,, this signal wil go in to the oscilator ,, and wil come out on the other side rx toy ,,, if you know where the signal wil go in and out , you maybe can use it for other type of signals ,,

I had a toy helicopter that was controlled by a radio remote, and the helicopter broke.

What happened to the transmitter? If that's what you're talking about, why do you need another one? Forget the term 'remote'. Use transmitter or receiver, to avoid confusion.

OK, I will join in the fray. Goodness knows why!

Your question is clearly confused. If the remote broke and the helicopter is working, you need to repair the remote. It is possible but not easy to use an Arduino to substitute for a given part of the remote.

If the helicopter broke however, the "remote" - the transmitter - is useless except for another helicopter of the same type.