Questions about RF, FM Transmitters and data rate.

[Meph1st0]

I've been thinking about this question/concern/speculation/thing for a few nights now and I just want to run it by you folks to see if I'm on the right track. I have the Ipod Photo 30GB that I am using in my car with the DLO Transpod FM Tranmitter. I primarily drive in Las Vegas, there are many radio stations in the area but I've successfully found a good frequency to use for my transmitter 106.1.

Although I have a bit of a problem-ish (it's really not that bad, but it has sparked this question). Some of the songs on my ipod sound nearly pristine. I don't hear much static at all with these songs. Though there are other songs where there's a bit more static (baerable, but I'd rather not have any). Anyway, this got me thinking about how the songs were encoded and the such. I thought about how I used to encode my songs, I used to think the higher the data rate the better the quality, so I used to drag the slider all the way to the top to 320Kbps without regard to hard drive space (hard drive space is so cheap now days I didn't care). Also, my primary preference was and still is, probably ignorantly so, just plain old MP3. I've tried to stay away from Apple's AAC as it is proprietary and I don't suspect I'll have my Ipod for the rest of my life.

This lead me to start thinking about another thing, the RF side. I know that my radio station uses about 200khz of bandwidth per radio station. I'm wondering if 320kbps is too high of a data rate to be squeazed into a 200khz FM radio signal. I guess the ultimate point of my question is, what is the highest data rate that can be squeazed into a 200khz frequency modulated signal? If it's less than 320kbps then perhaps that's the cause of the extra static?

Or just let me know if I am completely off the mark here, I have been known to do that on many occasions.

[Meph1st0]

Ok, here's the answer. It doesn't matter. The signal, albeit encoded at 320kbps, will be modulated onto an analog radio frequency and then transmitted at the best quality that my transmitter can handle. The radio doesn't care about the data rate at all, it merely amplifies and pushes out whatever analog signal it receives.

It's the same concept as simply trying to push a CD quality signal through a radio station. You'll never get the same clarity out of a radio station as you will with a CD.

I found out later that the songs with the extra static were not in fact encoded at 320kbps at all. They were actually encoded at 192kbps and lower.