I'm sorry to hear you're having this issue with viewing the full picture when viewing your Slingbox. It sounds like the signal isn't properly formatted. I would first try resetting the Slingbox and re-scanning for channels. If the issue persists beyond that, I would suggest reaching out to your cable provider to see if they can resend or reset the signal being sent through your coaxial cable.
Here is an article with steps on resetting your Slingbox:
Hope this helps!
The Sling Moderation Team
You obviously didn't read my question in that I don't have cable - the picture I get is directly from my HDTV antenna. The picture is perfect on my television and my HDHomerun via WMC, but the slingbox cuts off the picture.
I have already reset the slingbox with no resolution. Any other suggestions here? What would prevent the slingbox from slinging the entire picture without cutting out the top and bottom of the picture?