Volts multiplied by amps = Power in watts.
18 volts X .350 amps = 6.3 watts. So you have only 6-7 watts of power to drive a ku motor under the best of conditions.
Gear reduction is the key to moving a dish bigger than 1 meter. Usually the increase in motor speed will result in less motor torque due to the gear reduction. The only way to keep torque and increase speed at the same time would be to improve the efficiency of the motor, which is not likely ti happen any time soon.
Dish Motor manufactures are always introducing something new for us to buy. The increase in motor stroke (80 degrees West, 80 degrees East) could allow us to receive more satellites, but it also makes the motor work extremely hard when it is moved close to either East or West limit. 70 0r 80 Degrees to 0 is a very steep climb for a Ku motor.
Most Ku motors do not advertise a weight limit. They only tell you what size dish the motor will handle and this is very misleading. I do not see any way that a DarkMotor or any other Ku motor could handle a 1.4 meter dish without publishing the dish weight rating for the motor.
Stab is the exception.
Stab publishes dish weight ratings for their motors. The maximum stroke on a Stab HH120 is around 65 degrees, and it moves real slow when compared to some other Ku motors. But for the Stab, slow movement = more torque, which equals the ability to move more weight!
I own a Geosat 1.2 meter dish. A Stab HH120 moved the Geosat 1.2 meter dish for many years before I retired it. I never had any real problems with the HH120, but it did get slower over a period of time.
The HH120 was replaced with a Powertec DG-380. The DG-380 is faster, and it moves farther in each direction than the Stab did, but it has gotten stuck a couple of times at 15W. We do not have much snow and ice here in Atlanta, Ga. The Dg-380 would be in trouble if I had the extra weight of snow or ice to deal with. Extremely cold weather will make a dish motor work harder too. I have tested other Ku motors with similar results.
The bottom line from me is if you want to move a 1.2 meter dish using a Ku motor then get a Stab HH120. This motor is not cheap, and it moves slow. But for moving weight, it is second to none. EB