FM Transmitter mod help

Does anybody have any idea how to modify a car FM transmitter for an mp3 player so that it will transmit in frequencies other than the low and high extremes built into it? Also would it somehow be possible to make it transmit to all FM frequencies at the same time? If someone could help me out with this I would really appreciate it.

NachoMahma8 years ago
. Usually accomplished by adjusting the slug in an inductor or trimming a capacitor, but I'm no expert. If you can post the schematic, some of the electronics gurus may be able to help you out. Post the make/model and we may be able to help you find the schematic. . By over-modulating a little bit, you can splatter two or three channels (with increased distortion), but it's not really possible to cover the whole band.
kurdiz (author)  NachoMahma8 years ago
Ok, thanks. Yeah, I don't have a particular make/model yet, I was just wondering about the plausibility of the idea(The plan was to be able to talk to people in other cars without them knowing the source). But yeah, thanks. With an idea of what stations people around here like to listen to, I might be able to use this anyway.
. As BB points out, it will be difficult to talk over a commercial station when your transmitter is more than a few feet from the receiver ... unless you boost your power.
. If it's not out of your budget, you'd be better off getting a tunable FM Modulator and a linear amplifier.
. BTW, running more than a few mW is illegal. Check the FCC's web site (or the regulatory agency wherever you live).
Even if you pick the frequency they are listing to in there car, you'll have a hard time overpowering a commercial radio station.... And since you haven't bought one yet there is lots of FM transmitters on the market now that cover the entire FM band, most even offer digital frequency selection, and true Stereo transmission, there is even some that offer RDS so you can see the IDtag of the sone your listing to ....