On Mar 25, 11:11?pm, "ungvichian" wrote:
I've seen tons of posts about converting FM signals to AM signals
(say, to use with an AM only vintage car radio). But I haven't seen
anything about the inverse: converting an AM signal to an FM signal
(because there are quite a few FM-only devices on the market now, such
as MP3 players). I found this:http://www.uashem.com/pageid-259.html,
but it doesn't really fit my criteria. I'd like to be able to tune in
any AM station, and then select the frequency to output it to without
interfering with other station (think iPod transmitter).

Surely there's gotta be some out there...

If you need a small "converter" (of audio), all you need is a
frequency-modulated oscillator, the oscillator tuned to the
FM BC band of your choice. It can be a single transistor
with something like a simple variable capacitance diode (or
equivalent) doing the FM.

The circuit shown in your reference has no magic conversion
and is little more than a jammer of everyone in its tuning
range. If it works at all then it would be by overloading the
input of an FM BC band receiver and forcing it to be a mixer.
That is NOT good homebrewing since the same single-
transistor circuit could be converted to an FMed oscillator
with its output attenuated (to avoid undue radiation) and
loosely coupled to the FM receiver. If you have audio, even
if only from the speaker of an AM receiver, then you have
the modulation source...at audio, something you can hear
to make sure there IS a modulation signal input.

73, Len AF6AY