Sea Tel DAC-03, Installation And Operation Manual

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DAC-03 Tracking Antenna Controller Operation
2-11
If the antenna is already perfectly pointed, the signal received (AGC) throughout each full circle will
be equal. If the dish is slightly mispointed, a portion of the circle movement will have higher signal
level than the rest of the circle. DishScan will then issue a step in Azimuth, and/or Elevation, to
move the antenna in the direction of the stronger signal. [
EXAMPLE: If the dish is mispointed
slightly to the LEFT of the satellite peak; as DishScan drives the antenna through one circle rotation
it will evaluate that the signal is slightly higher to the RIGHT, therefore, a RIGHT (Azimuth UP) step
will be issued to the antenna].
The internal tracking receiver settings must be set correctly and the EL STEP SIZE , AZ STEP
SIZE and STEP INTEGRAL parameters must all be set to 0000 for DishScan to operate properly.
2.6.2. Internal Tracking Receiver settings
The internal receiver settings must be set correctly for either Tracking mode to be able to properly
peak the antenna on the desired satellite. Refer to the “Satellite” menu operation above and to the
“Selecting The Tracking Receiver Source” and “Tuning The SCPC Tracking Receiver” information
below.
2.6.3. C/X and Ku Band Selections
Band Selection must be set to the appropriate selection for Tracking to operate properly. For C, X
and Ku band systems the pre-set tracking parameters for DishScan can be changed in the
TRACKING window by pressing the
DOWN
arrow. The display will indicate which band is selected.
The EL STEP SIZE , AZ STEP SIZE and STEP INTEGRAL parameters will be set accordingly.
This selection also controls an External Tone Generator logic output on the Terminal Mounting Strip
AND remote C/Ku coax relays mounted on Dual C / Dual Ku Antenna systems.
2.7. Searching Operation
The ACU will initiate an automated search pattern after AGC falls below the current Threshold setting
(indicates that satellite signal has been lost). The SEARCH DELAY parameter sets the amount of delay, in
seconds, that the ACU will wait after AGC has fallen blow the threshold value before it starts a search.
Search can be initiated manually by pressing the MODE button twice to access the SEARCH sub-menu and
then press the UP arrow key (starts a search from the current antenna position). While in the SEARCH sub-
menu, pressing the DOWN arrow key will stop the current search.
Search is terminated automatically when the AGC level exceeds the threshold value and Tracking begins.
The ACU can be configured to use one of three search patterns. Each of the search patterns are described
below. Each description includes information about the settings involved in configuring the ACU to select
that particular pattern and the values that those settings would be set to, to optimize the pattern for your
antenna model and the frequency band being used.
The dimensions and timing of the search pattern are determined by the SETUP parameters SEARCH INC ,
SEARCH LIMIT , SEARCH DELAY and SWEEP INC . Search is also affected by the Threshold and the
internal receiver settings under the Satellite menu.
All three search patterns are conducted in a two-axis pattern consisting of alternate movements in azimuth
and elevation or along the polarization angle. The size and direction of the movements are increased and
reversed every other time resulting in an increasing spiral pattern as shown.
2.7.1. Default Standard (Box) Search Pattern
The factory default search pattern in the ACU is a standard “box” pattern. You configure the ACU
to use this pattern by using the following settings:
SEARCH INC - set to the default value for the frequency band that your antenna model is
currently being used for (typically 10 or 20 counts).
SEARCH LIMIT – initially set to the default value. After targeting has been optimized
(refer to Ch 5 in your antenna manual), the search limit can be adjusted if desired.