system
Given the following post, respond as if you're commenting on Reddit:
human
Why are FM radio frequencies always listed with odd decimals (.1, .3, .5 etc instead of .2, .4, .6)?
gpt
The RF spectrum was divided up into various bands for various uses by the FCC.  The band for FM radio transmission is 88 to 108 MHz.

From there there's a limit to how much information you can carry in an FM channel of a given band.  It turns out that having channels that are 200 KHz wide gives a good tradeoff between having lots of channels and having good quality, so that's what is used.

To divide the spectrum up into even parts without wasting any you start with 88.0-88.2, then 88.2-88.4, and so on.  This means that they're all even-to-even decimals.

The carrier wave in an FM transmission should be the center of the band, so for 99.6-99.8 you'd choose 99.7.  Since all bands run even-to-even the center is always an odd decimal.