Sea Tel COASTAL 18 Installation And Operation Manual Download

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Coastal 18 Ku-Band TVRO

Basic System Information

3-3

from you and how close you are to the Equator (refer to the polarization information in the Setup and the
Operation sections of this manual).

3.2. Antenna

Basics

The following information is provided to explain some of the basic functions of the antenna:

3.2.1. Azimuth

The antenna can rotate a total of 680 degrees between two mechanical stops. Azimuth drive, provided
by the azimuth motor, is required during stabilization, searching, tracking and unwrap operations of the
antenna. When the boat turns, azimuth is driven in the opposite direction to remain pointed at the
satellite. The actual azimuth pointing angle to the satellite is determined by your latitude & longitude and
the longitude of the satellite. It is important to know that the antenna should be pointed generally toward
the equator.

Refer to figure 3-1. The azimuth would be 180 degrees

true

(relative to true north) if the satellite is at the

same longitude that you are on. If the satellite is east, or west, of your longitude the azimuth will be less
than, or greater than 180 degrees respectively.

When checking for blockage you can visually look over the antenna radome toward the equator to see if
any objects are in that sighted area. If you are not able to find any satellites it may also be useful to
remove the radome top to see if the dish is aimed in the correct direction (towards the equator).

3.2.2. Elevation

The antenna can rotate up and down in elevation. Elevation drive, provided by the elevation motor, is
required during stabilization, searching and tracking operations of the antenna. The actual elevation
pointing angle to the satellite is determined by your latitude & longitude and the longitude of the satellite.
In general terms the elevation angle will be low when you are at a high latitudes and will increase as you
get closer to the equator.

Refer to figure 3-1. Additionally, from any given latitude, the elevation will be highest when the satellite is
at the same longitude that you are on. If the satellite is east, or west, of your longitude the elevation
angle will be lower.

3.2.3. Antenna polarization (Linear or Circular)

Your Coastal Series antenna can have a linear, or a circular, LNB installed.

When you are in an area where you want to receive

linear

polarized satellite signals, you will have to

install a linear LNB. When you have a Linear LNB installed, polarization adjustment is required when
initially setting up the system, when changing from one satellite to another and to compensate for the roll
and pitch motion of the boat when underway.

Polarization is

automatically

adjusted by the system when changing from one satellite to another,

periodically as the boat changes geographic locations by a significant amount of latitude and longitude
and to compensate for roll and pitch motions of the boat when underway.

The Polarization display will read 000 when the LNB is rotated full CW, 090 when the LNB rotation is
centered and 180 when the LNB is rotated full CCW (as viewed from the back of the dish).

When you are in an area where you want to receive

circular

polarized satellite signals, you will have to

install a circular LNB. When you have a circular LNB installed polarization adjustment is NOT

required

however, the auto-polarization function will operate as described above.