Been following your discussion, as I'm from Mangalore close to Kasaragod, and as a Cable Op I've noticed that C band signals drop down significantly as you move lower than Mangalore. In this case, I wouldn't suggest anything lesser than 12' , and you are asking for 6 or 8' ant for Kerala didn't make to much sense as the signals are dominantly digital and as such if the signal is less then you may not rx anything at all. BTW why don't you try at Mangalore, it may be available there too...