HD channels for DTV are on specific satellites for which you need all the specific LNB's and switches to combine these sats and LNB's..
DIRECTV 5 LNB Dish 5LNB Dish for DIRECTV (Slimline). Accesses Ka and Ku band DIRECTV satellites; required to receive high definition stations transmitted in MPEG-4. Backward compatible with all DIRECTV receivers. $149.00 - FREE GROUND SHIPPING
The new DirecTV HD channels require an H20/HR20 or H21/HR21 set top box (STB). In order to receive the new HD channels (channels added in late September 2007), viewers must have a B-Band converter installed. If the converter is not installed, viewers can only receive older HD channels (channels 70-99). The HR20 and HR21 are HD digital video recorder (DVR) models.
The new STBs support the ATSC standard (for over-the-air broadcasts) and also include QAM Tuner; however the H21/HR21 does not have an ATSC tuner. In addition, there is HDMI support for HDTVs with an HDMI port. New STBs also support MPEG-4 standard for HD Programming.
DirecTV is expected to offer new equipment in 2008 such as the AM21, an ATSC add-on for the HR21, the HR21-Pro, an HD-DVR for more recording space (100 hours HD, 400 hours SD), a DVR scheduler, and the HDPC-20, a PC type receiver and DVR for computers.
. DTV is now installing a dish that has five LNBs for HDTV programming and local channels in selected markets. These systems receive signals from up to 5 separate satellites in both the Ku-band and Ka-band. After the new satellite, DirecTV 11, is fully operational DirecTV will stop supplying Dual, Triple, and 5-LNB dishes to all customers and move to Supplying a 3-LNB Ka/Ku dish known as the Slimline3. This dish will see orbital locations 99, 101, and 103 Degrees West. The Slimline3 will be the new standard install dish(For HD and SD programming), while the 5-LNB Slimline will be used for installs in areas that receive local or international programming form orbital locations 110 or 119. The Slimline3 looks nearly identical to its predecessor, aside from a smaller LNB.