Oh, and for the record ...
A "B-Band Converter" (or "BBC") is just that. A device to allow receivers operating in legacy mode to receive the Ka "B" or "lo" band, which is used by various DIRECTV satellites at 99 and 103W for both local and national programming. That originally downlinks between 18.3-18.8 GHz from those two satellite positions.
Legacy Ka/Ku/(and now)RB LNBs down-convert the received Ka B-band signals to between 250-750 MHz on the coax, however all tuners used by DIRECTV HD receivers, except the H/HR-23 models, can only receive between 950-2150 MHz in both legacy and SWiM modes.
So whenever the receiver needs to tune programs on the B-band, it activates the BBC (via a special DiSEqC command) to block out the actual 1650-2150 MHz "A" or "hi" band range signals on the coax. And then up-converts the 250-750 MHz range to 1650-2150 MHz as a replacement.
