It would be to your advantage to make the pole as short as possible and still get a good line of sight. The longer the pole is; the longer the lever arm and the pole's likeliness to whip in the wind.
You could, however, get yourself a larger diameter section of pipe, some three to four feet, and place it over the bottom section of the current pole and fill it with concrete. That would stiffen the pole. The new vibrational mode would make the pole a shorter wave, making the pole a 1/2 instead of a 1/4 wave length. This would, in effect dampen the vibration or whipping of the pole with the dish on it in the wind.
Also, placing more concrete around the base will also steady it. In engineering structual foundations, when depth cannot be achieved, a wider base serves the same purpose.