1) I dont think $100 for a HR20-700 would be a purchased unitpeano said:
2) BBCs (B Band Converters) are devices that you do need to watch the newer MPEG-4 HD channels
3) The dish will be a 5 LNB type
4) UHF capabilities? If you mean for OTA reception yes it has an OTA tuner built in. If you mean can you locate the unit in one room and watch something in another, yes you can. All the outputs on the back of the unit are active.
If you do a little lurking you will see things mentioned about SWM and SWMLine dishes that could also change the equation. If youre confused =, keep posting and we'll all keep answering.