Dawn CONTROL-1500A Manual page 2

O P E R A T I O N A L O V E R V I E W
The RC1500 was designed to provide years of reliable operation
through the use of a heavy duty solid-state drive network coupled
with a novel microcontroller-based fault monitoring system. The 5
amp rated drive output capability is adequate for either moving
feed trackers or full-size linear actuators and the Adapti-Drive
digital servo speed control optimizes antenna movement for
today's demanding Ku-band applications. Additional features like
an RS-422 communications port for PC control and a very user-
friendly, menu scheme make the RC1500 a unique and highly
adaptable piece of equipment. Overall, the RC1500 is well
equipped to handle the demanding requirements for cost sensitive
domestic and international inclined-orbit satellite tracking.
T R A C K I N G A L G O RI T H M
When using a modest-sized antenna in which the beam may be
steered along the declination axis, (perpendicular to the
geostationary arc) a satellite that is in an inclined orbit may be
tracked with a single-axis antenna controller. The angular width of
the "figure 8" pattern of the satellite's apparent motion is, in
general, very small.
approximately:
W = 1.2 x (inclination)
or 0.26 degrees for a satellite with an inclination of 5 degrees.
If the antenna beamwidth is larger than the width of the figure 8, it
can track the satellite with single-axis, declination motion. An
11.5m C-band or an 3.8m Ku-band antenna would have a 3dB
beamwidths of about 0.6 degree.
antennas could track the satellite with less than 3dB error.
The tracking algorithm used by the RC2000 antenna controllers
can be divided into 3 distinct parts - STEP_TRACK,
PROGRAM_TRACK and SEARCH. To initiate the track process,
the user jogs the antenna to the satellite and verifies the identity of
the satellite. The system then enters STEP_TRACK mode.
In STEP_TRACK mode, the controller periodically peaks the
receiver's AGC signal strength by jogging the antenna. The time
and position are recorded in a track table maintained in the
controller's non-volatile memory. The interval between peakups is
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You are entitled to the manufacturer's limited express warranty, if any, that accompanies the product. DAWNco
All other warranties, express or implied, including the warranties of merchantability and fi fi tness for a particular
We are not responsible for any typographical, photographic or technical errors. See "Policies for DAWNco" under
For the mid-latitudes, this width is
/ 115
2
Properly aligned, these
makes no additional or independent warranty.
purpose are disclaimed. We do our best to be accurate.
determined by antenna beamwidth (as determined from antenna
size and the frequency band), satellite inclination, and a user
specified maximum allowable error (in dB). STEP_TRACK mode
is active until a time is reached that corresponds to a segment of
the satellite's motion which has previously been stored in the track
table. When this occurs PROGRAM_TRACK mode is activated.
In PROGRAM_TRACK mode the controller smoothly moves the
antenna to azimuth and elevation positions derived from entries in
the track table. The time between movements is determined by
the same factors which govern the time between peakup
operations in STEP_TRACK mode. In particular the user can
specify the maximum allowable error between the antenna's actual
position and the position specified by the track table.
increasing the maximum allowable error, antenna movements can
be performed less frequently, thus avoiding unnecessary wear on
the antenna actuators. In PROGRAM_TRACK mode the accuracy
of the track table is monitored by periodically peaking up the
receiver AGC signal. If the error exceeds a level set by the user,
all entries in the track table are flagged for update. The period
between these accuracy checks is specified by the user and
typically varies from once a day to once a week.
SEARCH mode is entered from STEP_TRACK mode when the
satellite signal has been lost. When the satellite is located, the
controller re-enters the STEP_TRACK mode.
SP E CI F IC A T I O N S
PHYSICAL PHYSICAL
19.0" x 3.5" x 9.0" (rack)
Size: Size:
8.5 lbs.
Weight: Weight:
0
Temperature: Temperature:
115 / 230 V A C, 50 / 60 Hz., 40 W
Input Power: Input Power:
TRACK MODE TRACK MODE
0.4 – 5.0 meters
Antenna Size: Antenna Size:
+ /- 10
Maximum Inclin a- a- Maximum Inclin
Search, Step Track, Program
Tracking Modes: Tracking Modes:
Track
AGC Input: AGC Input:
0 to +10 V D C input ran ge, 2MΩ
input impedance
DRIVE DRIVE
36 V DC, 10 A mps; 150 V A
Output: Output:
Pulse-type: Reed, H all Effect, O ptical
Sensor Input: Sensor Input:
Standard Polarotor
Polarization: Polarization:
optional rotatin g Feed-drive at
voltages from 5 – 36 V DC @ 2 A max
o o
– 50 C
o
standard
TM
Interface,
By