ViP612/622/722/722K DVR Support Forum
I belive there are 2 reasons for the DPP44. One is a LongDukDong says--if you have 4 satellites. The other is if you need to use a dual-tuner receiver with only one coax line.
If you get rid of the 301, you will have 5 tuners (4 receivers, one with a dual tuner). This could be supported...