It is a Winegard Manual crack up Satellite Dish. On the inside of the trailer/motorhome directly under the dish itself, you will find the manual controls for it that extend it and control the elevation and rotation. It was used with either Dish Network, Expressview (Canada) or Direct TV, which one can be determined by the model of the LNB on the end of the arm once the dish is extended and fully visible
Most likely a very old model and no longer usable based on the LNB the photo shows. There have been many changes in satellite technology over the recent years including the use of multiple satellite reception and HD broadcasting for any give service. This one, very similar to mine, except for the LNB, was limited to a single satellite reception. Mine is more round than oval in shape, was installed around year 2000 and has no skew adjustment needed for multiple satellite use.