BLOG 10:
Capacitor field Upgrade available
We found that the motor noise filter scheme used in the first production models is not as robust as we had thought. The Elevation motor and optical sensor output signal travel through a 36 inch cable between enclosures. This allows for greater inductive coupling of motor induced noise into the Optical sensor signal.
Early in the design of this product, we found that the PWM motor control process was causing early motor brush failure. The back EMF caused by the switching of the motors was to blame, and the heavier the load, the greater the noise pulse. In the Ultra-Portable Rotor product we used a capacitor a crossed the motor terminals to reduce the motor noise. We moved to a MOV to ‘snub’ the motor induced pulses caused by the PWM operation. Well it seems that the MOV is doing a good job at catching the low frequency noise that contains the majority of the energy, but not the high frequency noise. By adding a capacitor in parallel with the MOV, the high frequency noise is greatly reduced.
This upgrade will help improve performance when you are aiming off center loaded antennas. See the Resources page for details on how to do the upgrade.
So, any system shipped prior to July 20th will not have this modification. Contact us at support@portablerotation.com if you want us to send you the 4 0.01uf Capacitors or wish to arrange to send the Azimuth (Base) unit back for the upgrade.