I just got an H20, and the installer put it in line with the input- it's described as a B-Band converter for Ka-Lo band upconversion. Since Ka-Lo band is 250-750 MHz, and the H20 receives signals 950-1450 MHz, the SUP-2400 upconverts this signal. If you don't install it, you shouldn't receive the B-Band. The installation guide further states if you already have an FTM (Frequency Translation Module), this SUP-2400 is not needed, since it does the same function. Hope that helps.