Research Concepts RC2000A - Manual (Page 114)

114 RC2000A Dual Axis Antenna Controller Appendix I 2.6x Addendum
Azimuth CW Limit and Azimuth Position
Setting the Azimuth CW Limit CONFIG mode item also initializes the Azimuth CCW Limit to 30.
Normally these limits are set via LIMITS mode. The Azimuth Position count is normally set to 30 when
the Azimuth CCW Limit is set via LIMITS mode. The Azimuth Position count can also be set via RE-
SYNC mode.
Elevation Up Limit and Elevation Position
Setting the Elevation Up Limit CONFIG mode item also initializes the Elevation Down Limit to 30.
Normally these limits are set via LIMITS mode. The Elevation Position count is normally set to 30 when
the Elevation Down Limit is set via LIMITS mode. The Elevation Position count can also be set via RE-
SYNC mode.
4.4 Polarization Control Options
In the v2.6x revision of the RC2000A software the Rotating Feed Present CONFIG mode item has been
replaced with the Pol Control? CONFIG mode item. At the Pol Control CONFIG mode prompt the user
can specify either None, One Port, Two Port, or Polarotor. At the Rotating Feed Present CONFIG
mode prompt found in earlier versions of the software the user could specify No for polarotor control or
Yes for a (one port) rotating feed.
The following paragraphs describe the various possible responses to the Pol Control? CONFIG mode
prompt.
1. If the user enters None at the Pol Control? prompt the controller assumes that a polarization control
device is not present in the system. Polarization jog commands are ignored and the user is not
prompted to specify polarization values in SETUP mode.
2. One Port refers to a single port rotating feed powered by a DC motor that employs a potentiomter
for position feedback. This type of feed can only receive a single signal (and only has one LNB).
When a single port feed is looking at a satellite that transmits both horizontally and vertically
polarized signals, the controller has to ‘remember’ both a horizontal and vertical position for each
satellite. Accordingly, the user is prompted for horizontal and vertical polarization positions in
SETUP mode. If this option is specified the RC2KPOL polarization control daughterboard must be
installed in the controller. Setting the Pol Control? CONFIG mode item to One Port results in
controller operation identical to that of older versions of the software with the Rotating Feed Present
CONFIG mode item set to Yes.
3. A two port feed can receive horizontally and vertically polarized signals simultaneously. Like a one
port feed, a two port feed is powered by a DC motor, employs a potentiometer for position
feedback, and requires that the RC2KPOL daughterboard be installed in the controller. In SETUP
mode, when a single band (either C or Ku) satellite is specified the user is only prompted to specify
a single polarization. When the feed is adjusted to that position it can receive horizontally and
vertically polarized signals simultaneously. In SETUP mode, when a dual band satellite is specified
the user is prompted to specify both a C Band and Ku Band polarization position (they can be set to
the same value).
This behaviour for dual band satellites when a two port feed is specified is designed to
accommodate the Seavey Engineering Associates ESA 124D feed. The ESA 124D feed can
simultaneously receive horizontal and vertical signals for both C and Ku bands. Most satellites that
include both C and Ku band transponders (also know as hybrid satellites) have identical horizontal
and vertical polarization orientations for C and Ku band. Some satellites, however, do have unique
H/V polarization orientations for C and Ku band.
4. A polarotor is a 3 wire servo developed by Chaparral Communications. A polarotor is a single port
device (meaning it can only receive a single signal for a given band). Some polarotor based feeds
can receive C and Ku band signals simultaneously.
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