In another thread, there was a discussion about how much of the arc you could see with an un-modified
C-band dish driven with an
actuator. A couple people here were reporting being able to get to a large percentage of the arc with an actuator, while my past experience was that without modifying the actuator's connection to the dish, that this wasn't possible. Well in that thread, I said I was going to go out and look at my 6' dish, to see how it was connected (my past experience was with a 10+' dish).
Well, I looked at the dish, and it is connected much differently than my old 10' dish, and the differences are interesting... to me at least. On my old 10' dish, the motor end of the actuator connected behind the mount, and the piston end connected directly to the dish itself, almost half way out along the dish surface. What would happen would be when the actuator pushed far enough that the line of the actuator was a tangent to the arc of the dish, then the actuator would jam against the side of the dish. This jamming occurred at some angle past due south. I can't remember exactly, but I could go maybe 25 degrees past due south. The cure, that people on the web came up with was to bring the connection point out away from the dish so the actuator doesn't jam.
On looking at my 6' dish, the motor end connects behind the mount like on the bigger dish, but the piston end connects to about a 17" long piece of angle iron directly at the rear center of the dish. Ie this angle iron sticks out and has connection points at about 8" to the east of center and 8" to the west of center. Ie with the 6' dish, the connection point is much closer to the center of the dish. And in addition the further out the 8" (there are a couple connection points), the further you get from the arc of the dish. There is no way this connection can jam, like it did on my 10' dish. I ran the dish back and forth a couple times with my hand drill, and I noticed that although the dish didn't jam against the dish, it did, however jam against the mount itself. This occurred about 40 deg east of due south. Also, this dish doesn't seem quite capable of getting all the way to the western horizon, because the angle iron would jam against the mount before it got to the horizon.
On looking at this arrangement on the 6', it occurred to me that this would work pretty well if the angle iron were longer than 17", although it would take a longer actuator. This particular dish, which I bought used, along with a receiver (I only wanted the receiver, but the guy wanted to get rid of the dish), came with a small actuator (I think it was an 18"). Also, the further out the connection point is, the more mechanical advantage you have when trying to lift the dish from the horizon. However extending the connection point might mean that it would be even further from reaching the western horizon. But I think that if I was going to use this dish motorized, that I would extend that angle iron a bit. I think that if it extended another 4" in each direction that I could extend the range to maybe 60 deg to the east.
Anyway, I see that there are at least a couple different ways of connecting actuators, and each seems to have it's advantages and disadvantages.
Linear Mode
