Could be a 1.2 Meter. Look at the back of the dish and see if it may have Channel Master brand name on it. It should have the size on it too. Seems like the name on front of the dish and on the LNB cover was the Satellite company (like Primestar) that was offering satellite services some years back.
That dish you saw would be great for FTA! I got two of them.
The photo doesn't do justice to the size. For a reference, compare the reflector to the shingles on the roof. I took the photo from about 10 ft away.It's definitely much smaller than my 1m Primestar dish. I got as close as possible while standing on the fence post. It's mounted on top of a shed next to the railroad tracks.
OK...then it may be a .75 meter, like the one in these photos. I took care in trying to duplicate your camera angle. The top lip to bottom lip dimension is roughly 32 inches.
Smaller than what is generally considered necessary for good all around FTA performance, but it probably has tighter geometric tolerances than most consumer grade FTA dishes ... some day I will get around to doing a little field testing.