UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Poor Man's Rotator Using a Stepper Motor?

G6Tanuki · 12th Oct 2018, 4:43 pm

You'd need to gear it down quite a lot in order to get enough torque. Steppers - because they move abruptly and in pulses - don't really deal with 'loads' that have much inertia.

A stepper is a good way though of driving a loop-tuning capacitor: the old AEA "Isoloop" used a stepper-motor which drove the tuning capacitor through a toothed belt and pulleys, which provided a good reduction-ratio as well as isolating the stepper from the RF-hot capacitor-shaft (so it didn't upset the electrical balance of the loop).

See here for a breakdown of an Isoloop including the stepper drive: https://frrl.wordpress.com/2009/03/2...-loop-antenna/

12th Oct 2018, 4:43 pm	#2
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,010	Re: Poor Man's Rotator Using a Stepper Motor? You'd need to gear it down quite a lot in order to get enough torque. Steppers - because they move abruptly and in pulses - don't really deal with 'loads' that have much inertia. A stepper is a good way though of driving a loop-tuning capacitor: the old AEA "Isoloop" used a stepper-motor which drove the tuning capacitor through a toothed belt and pulleys, which provided a good reduction-ratio as well as isolating the stepper from the RF-hot capacitor-shaft (so it didn't upset the electrical balance of the loop). See here for a breakdown of an Isoloop including the stepper drive: https://frrl.wordpress.com/2009/03/2...-loop-antenna/