I have found Dish networks site to have every answer I have ever needed...
Solo ViPÂ® 211k
Supports one independent HDTV with remote control
Compatible with Tailgaterâ¢
View over-the-air SD and HD broadcasts (requires optional over-the-air module).
On-screen Caller ID with history (optional).
1) It makes no difference if the HD is attached.
2) It is not a DVR receiver so I don't believe the USB can be used.
3) It requires the optional OTA module as noted above from Dish.
5) Best to ask Dish to make sure of any charges - their chat functions is quite good and can be used to verify all of the above as well.
There are reviews on Amazon...:
"It drops into your stomach like a Abrams's tank.... driven by Rosanne Barr..." A. Bourdain