Thanks for your question! It seems the Galaxy Note 3 has a display resolution of 1280 x 800. The Slingbox streams in 1280 x 720. The reason you still have a black bar at the top and bottom of your screen is because of the format that the Slingbox streams in is lower then the display resolution the Galaxy Note 8 tablet uses. To help fix this issue, I would recommend changing the aspect, and zoom settings within the SlingPlayer application on your tablet.
This article can further explain how to manipulate these settings:
If you have any other questions, feel free to respond or give us a call at 1-877-467-5464. We are open seven days a week, from 10:00am to 10:00pm EST.
Hope this helps clear things up!
The Sling Media Moderation Team