DIRECTV HD DVR Dual Tuner Issues

[stewart715]

The DIRECTV HD DVR (HR20) does not require two lines to receive programming. However, I do not receive all HD channels with one line (getting service errors, etc.)

I'm using a Slimline 5-LNB dish with a B-Band converted attached.

Any suggestions how to correct this without adding a second line?

 

[Zynergi]

What are the service errors you get and What does channels 480 and 481 return?