Difference between a Linear and Circular LNB
This has to do with the way the signal is transmitted from the satellite in the sky.
There are two different ways that a satellite can broadcast its signal. If linear, it broadcasts Horizontal and Vertical.
If circular, it broadcasts Right Circular and Left Circular.
To understand this better, imagine the signal coming in like a screw that's turning left or right.
Understanding Circular & Linear Polarizations
insert a tufflon plate like this, to receive circular polarizations