Just found this on the Directv website about the 498 channel on the directvHD equipment tab.
The easiest way to tell if your H20/H21 or HR20/HR21 receiver has the BBC connected to it is to look at the back of the receiver. Look for a module that looks like the one pictured to the right. If you can't access the back of your receiver and you have an HD receiver, tune in to the BBC test channel — number 498:
* If you get a message on your screen telling you that your HD setup is correct, you're all set to enjoy the new HD channels from DIRECTV as they become available.
* If you see the message "Searching for Satellite Signal," you do not have the BBC or it is not connected properly.
* If you see a gray or blank screen, DIRECTV will have to verify your equipment setup to determine if you need a BBC. Please call Customer Service at 1-800-531-5000.