Better sound quality for the car FM transmitter
Topic: car DIY
If you want aux input for your car stereo, a common option (often the only low-cost option if your stereo does not have an external input of any kind) is to use an FM transmitter (modulator). But if you live in a metropolitan area like me, there will be almost no FM frequency that doesn't have interference so the sound quality won't be satisfactory.

So what I tried doing is to directly wire the antenna from the FM transmitter to the antenna input of the car stereo.

The result: Much better. Without the wire, I had a hard time getting a stereo signal but now that's relatively easy. However if you want a real good sound, I would recommend buying a FM modulator that switches between a direct connection and the car antenna. PIE seems to be a popular manufacturer of such and other devices. Or better yet, buy a car stereo that has AUX input or is AUX input capable.