The Actuator
Many satellite reflectors are fixed on a single satellite
for particular reception needs. However, far greater reception possibilities
exist when a system can be equipped to move across the satellite arc to receive
signals from several different satellites. The most common actuators are linear
(pictured) and use a 24 or 36 volt DC motor which is controlled by the satellite
receiver. The actuator chosen depends on the reception needs, the size and weight
of the reflector and the look-angle available at the site.
Linear actuators come in various lengths and designs, each with their own qualities and performance ratings.
Terms such as " acme ", "ball screw", "pulse count" and "length" all contribute to the actuator
decision making process. An "acme" actuator utilizes a simple screw mechanism to
move the reflector. It is very smooth and quite in operation and will generally carry the smaller reflectors'
weight load. A "ball screw" actuator utilizes a ball-bearing assembly to drive
the screw mechanism and is much stronger but a bit more noisy. The "pulse count"
refers to an actuators' internal sensor which the receiver will use to repeatedly drive the actuator to
specific satellite locations. The "length" of the actuator describes the amount
of allowable movement. Generally, most 18 inch inch actuator arms will allow for reception of the complete
domestic satellite arc while 24 and 36 inch actuator arms provide for increased arc coverage. A 24 inch, 40
PPI (pulse-per-inch) is considered nominal for the continental USA.
The Reflector
The Feed Assembly
The Actuator
The Receiver
FCC Fact Sheet
For additional Full-Arc Satellite Systems information: sodac@sodac.com