Instruction manual

www.alfaradio.ca AlfaSpid Rotator Page 17

Page 17 of 23

lfa Radio Ltd. 11211 - 154 St. Edmonton, Alberta, Canada T5M 1X8 780 466 5779

AlfaSpid_Rotator_RAK_Manual_Sept15_2008.doc

Using the

lfaSpid Rotator with LONG Cable Distances

By VE6JY

Since the motor uses relatively low voltage DC, a combination of long cable

runs and/or thinner than required cable may reduce the voltage at the motor to an

unacceptably low value. It may turn in warm weather or light winds but the power

will not be available to rotate under more severe conditions.

While it is easy to say just use a heavier cable, this may be costly,

impractical or both. I have one tower that is over 1700 feet (approx 500 meters

away) and running large cable out there would be very expensive.

My solution is to use this rotator controller's output voltage to control another

set of relays that will feed a higher voltage DC to the motor. In the above-

mentioned example, I find a voltage between 60 to 80 volts gave suitable

performance. This is a pretty extreme case but it illustrates the versatility of this

design. The external DC supply voltage needed will vary depending on the DC

voltage rating of your motor, the cable size and length of the run. Typically 36 to 50

volts at 3-5 amps should be quite adequate. These DC motors are quite tolerant on

their voltage ratings.