welcome. Unfortunately, UPN HD or any Network Broadcast would not allow to have a national HD feed transmitted to every single household in the US through satellite. Your local broadcaster (UPN as it maybe) will blocked this and so will any local broadcaster from any network. It is unfortunate that it is this way. There should be ONE local channel for each Network broadcasted nationally but it is not going to happen any time soon.
Your best bet will be to get it OTA and put pressure on your local UPN to go HD.