I have a rotating satellite dish setup with a linear actuator and a 150 cm gibertini dish. The actuator is a heavy-duty type that can handle serious load, and it has worked flawlessly for years. With this setup I can see roughly from 35° West to 80° East. So far, so good.
However…
A few days ago I started playing with it: I disabled the east limit and checked what the physical eastern boundary was. To my delight, I discovered that just before the motor physically stops — meaning just before it fully contracts and can’t go any further — I can still barely lock the signal at 80° East, with a good signal level.
That was two days ago.
Since then, however, I’ve noticed a new issue: when moving towards the east, the motor started to become inaccurate. First I realized that all my stored satellite positions (I use a Primesat PR1200 positioner, without USALS) needed readjustment — I had to move each one about 8–9 steps eastward to bring the satellites back.
But now even that doesn’t hold. If I drive the actuator far east, and rotate a bit left/right there, then move back to a satellite further west, the motor consistently “overshoots” the position by 7–8 units. And even if I correct it and store the new value in the positioner, after doing a sweep across the horizon and returning, the same stored position is wrong again: I must once again correct it by 7–8 units eastward. Always eastward.
The motor overshoots slightly west every single time. It never used to do this.
It’s as if starting from the eastern satellites and moving westwards, the motor makes a tiny movement that the positioner does not register. As a result, all following positions become inaccurate.
It’s important that the dish does not drift off the orbital arc — with correction I can always restore maximum signal on each satellite, so I’m confident all bolts are tight everywhere. So the mount is not rotating on the pole. If it were, we would slowly drift off the arc and eventually lose all satellites.
We remain on the arc; the motor just stops in the wrong place. Connecting this fact with the observation that the problem began right after I pushed the actuator to the extreme eastern limit, I dare to conclude that something at the motor level is not okay. Or possibly the positioner.
Do you have any ideas regarding this issue? Please let’s start with the simplest possibilities — replacing the motor, throwing it away, or replacing its internals should not be the first options.
Thank you in advance.