This issue occurs on a TV to TV basis and is from different manufacturers. Sometimes this can be corrected in the settings of the TV. There is also a screen size adjustment setting found in the Settings>Audio/Video of Mohu Channels which will allow you to adjust your picture.
Important: Mohu Channels has been discontinued and is no longer under warranty. Some third party retailers may still sell Channels units, but they are not covered by any Mohu warranty.
Please contact the reseller if you have any questions.