OK Thoken here is the problem. You are not answering the question about the transmitter itself. Is it a am radio and does it say AM or FM anywhere on the Transmitter?

Now where did the Receiver come from, was it the original receiver that came with this transmitter? Does it say AM or FM anywhere on this receiver and if so which?

Heres the deal if you have a AM transmitter then you must have an AM receiver. In addition to this I beleve the crystal you bought for the receiver is a FM crystal but if this transmiter and receiver is AM units then that crystal must be an AM crystal.

John