RIGHT: FatCat Radio

WRONG: Fat Cat, fat cat, Fatcat, FatCatRadio

The name of the station located at www.fatcatradio.com is FatCat Radio.
FatCat. All one word. Capital F. Capital C. FatCat.

It is NOT any of the following:

Fat cat Radio
Fat Cat Radio
fat cat Radio
Fatcat Radio
FatCatRadio

It is FatCat Radio.
FatCat. All one word. Capital F. Capital C. FatCat.

See also:
The name: (Wikipedia)
The # 1 rule: (Cat's Meow)