We were just in Yuma, we have a 630 PVR and we didn't have a problem getting HD channels, but I didn't check the channels that use the new third sat that is ranged so you can't get signals south of the US/Canada border. I have an automatic Winegard dish.
We tried to help a fellow Canadian friend in Yuma with a tripod, he had two receivers and couldn't get HD channels either. We tried better aiming (got a 92 SS) and changed the LNB without success. One theory, it may be the aiming process with the tripod (thinking that we hit the wrong sat, Shaw's 2 sats are only 4 degrees apart). The other possibility is that some receivers are programmed to look for the HD channels off the new sat, I noted that our friend's channel mapping was different than ours.