21-09-2016, 02:02 PM
Hello,
over time I have been working towards a small EME station, one aspect has always presented a hurdle, how to move the antennas slowly enough to track the moon without over shoot of direction control. As normal motors need time to spin up and spin down there is generally some degree of over or under shoot of the mark.
I have a rather large and unique gearbox /rotator that came from a VK3 back in June, it was advertised on VKHAM and is a made by a US company called: Houston Fearless
Will post a photo or a link to it soon.
This thing stands 1.2 meters tall and has 900 x 900 mm footprint, it uses a very large worm drive to create rotation and had a 100V AC motor to provide the grunt (reverse the field connection to go in reverse). While testing its operation it became apparent the speed was a bit fast for my liking and even though it used a magnetic brake to reduce over run it still was hard to be accurate with it like this.
I have always had stepper motors in the back of my mind to be the motor for a rotator on my EME system as they can be pulsed to provide small known steps in rotation and hence provide small increments of azimuth BUT now comes the crunch, have others out here in the blogeshpere had any real world experience with these beast as to how much torque they can generate or are they gutless beasts not suitable to drive a gearbox?
Regards,
Peter, vk5pj
over time I have been working towards a small EME station, one aspect has always presented a hurdle, how to move the antennas slowly enough to track the moon without over shoot of direction control. As normal motors need time to spin up and spin down there is generally some degree of over or under shoot of the mark.
I have a rather large and unique gearbox /rotator that came from a VK3 back in June, it was advertised on VKHAM and is a made by a US company called: Houston Fearless
Will post a photo or a link to it soon.
This thing stands 1.2 meters tall and has 900 x 900 mm footprint, it uses a very large worm drive to create rotation and had a 100V AC motor to provide the grunt (reverse the field connection to go in reverse). While testing its operation it became apparent the speed was a bit fast for my liking and even though it used a magnetic brake to reduce over run it still was hard to be accurate with it like this.
I have always had stepper motors in the back of my mind to be the motor for a rotator on my EME system as they can be pulsed to provide small known steps in rotation and hence provide small increments of azimuth BUT now comes the crunch, have others out here in the blogeshpere had any real world experience with these beast as to how much torque they can generate or are they gutless beasts not suitable to drive a gearbox?
Regards,
Peter, vk5pj
Peter Sumner, vk5pj
You have enemies? Good. That means you've stood up for something, sometime in your life.
- Winston Churchill
You have enemies? Good. That means you've stood up for something, sometime in your life.
- Winston Churchill