Release 1
DAMS-NT DigiRIT Operation Manual
12/14/2012
Microcom Design, Inc.
15
2.
DAMS-NT DigiRIT Hardware Setup
2.1.
Antenna Installation
If the DAMS-NT DigiRIT system includes an optional satellite antenna, it must be installed and
aligned for proper operation.
To install the satellite dish, follow the third party manufacturer’s installation instructions
provided with the dish.
Once the dish is installed, mount the front-end to the dish following the satellite dish and front-
end manufacturers’ instructions.
To align the dish, three things must be known: 1) the elevation angle, 2) the azimuth compass
pointing direction, and 3) the polarity skew. All three of these items are a function of the
location of the dish and the desired GOES satellite that will be utilized to receive the LRIT
signal. Microcom recommends utilizing the website
www.DishPointer.com
to determine the
required pointing information. This website allows the user to enter the location of the dish
either by a street address or by latitude/longitude coordinates and provides a drop-down list of
geosynchronous satellites, including GOES-East and GOES-West. DishPointer also has
numerous SmartPhone applications available (for a small cost) to facilitate the dish alignment
process.
Once the required pointing information is known, the first step is to set the elevation using an
inclinometer; LRIT receive systems utilize a prime focus dish so the angle of the dish should
exactly match the elevation angle. If the azimuth is going to be set using a compass, be sure to
utilize the “magnetic” direction, not the “true” direction. Alternately, the DishPointer website
and applications provide a line-of-site indication overlaid on a satellite map, which allows
accurate azimuth alignment by simply selecting a distinct object to point the dish at.
The front-end or feed polarity is set by loosening its mounting hardware and rotating it to match
the polarity angle or “LNB/LNA Skew” accordingly. Note that polarity angles or skews are
relative to the sky view, i.e. looking through the dish/front-end at the satellite, and can have
positive (clockwise) and negative (counter-clockwise) values. However, most feeds have their
polarity indication on the back side of the unit, so one typically sets them while looking at the
dish. One must be sure to take this direction reversal into account when setting the polarity from
the back-side of the feed.
Once the dish and front-end are installed and aligned, all the remains is to connect the RF coaxial
cable to the feed. Typically, the feeds require the cable to be terminated in an N style connector;
consult the front-end manufacture’s information for the proper connector. Most front-ends
require a DC power source, which is supplied via the same coax cable the returns the LRIT
signal.
2.2.
DigiRIT Receiver Installation and Hardware Overview
The Microcom DigiRIT Receiver requires very little hardware setup beyond performing the
connection of the various cables. Further, if the user provides Microcom with the necessary
information, the DigiRIT Receiver will be factory configured to be plug-and-play. For most
installations, only two cable connections will be required at the receiver besides AC Power.
Specifically, an Antenna IF Input connection and the DCS TCP/IP connection.