Sea Tel 6012-12w Installation Manual Download

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Setup – Blockage & RF Radiation Hazard Zones

6012-12W Installation Manual

Setup – Blockage & RF Radiation Hazard Zones

The Blockage Zones function inhibits the antenna from transmitting within certain pre-set zones. This is typically
some structure of the ship that prevents satellite signal from getting to the Sea Tel antenna when the ship is at
headings that put that structure in-between the satellite and the satellite antenna,

However, it can also be used as an RF Radiation Hazard zone. If there is an area where people may be near the
antenna (within 2 meters), in the antennas transmitted beam for extended periods of time the zone can be set up so
that transmit from the satellite antenna will be disabled whenever the antenna is pointed in that zone.

7.1.

Radiation Hazard and Blockage Mapping

The MXP can be programmed with relative azimuth sectors (zones) where blockage exists or where transmit
power would endanger personnel who are frequently in that area. Your MXP software allows you to set four
zones.

When you create these

ZONES

(up to four), several things happen when the antenna is within any one of the

zones:

Tracking continues as long as the AGC value is greater than the Threshold value. When the AGC
value drops below Threshold, the antenna will wait “Search Delay” parameter amount of time and
then re-target the satellite you targeted last. Timeout and re-target will continue until the satellite is
re-acquired and tracking can resume.

The satellite modem transmission will be
disabled until the antenna exits the zone.

The lower and upper azimuth limits are entered into the

REL start, REL stop and EL fields within the MXP for each

the blockage zones you wish to create (up to four). Each
zone can also be given a name (ie Mast, Deckhouse or
Stack:

REL Start

is the Lower Relative AZ limit (this is

the more counter-clockwise of the two points,
even if it is numerically larger).

REL Stop

is the

Upper Relative AZ limit (the more clockwise of
the two points) for pattern mapping of each.
Enter the elevation value that represents the
top of the blockage between the two azimuth
limit points in the

field.

Repeat for up to four zones, click SAVE when
completed.

Programming instructions:

Determine the Relative AZ positions

where

blockage, or

Radiation Hazard, exists. This may be done by

monitoring the received signal level and the REL display

readings while the ship turns or by graphing the expected blockage pattern. Elevation of the antenna in
normal use also must be taken into consideration. A Mast or other structure may cause blockage at low
elevation angles, but

may not

cause blockage when the antenna is at higher elevation angles where it is able

to look over the structure. Up to four zones may be mapped. Only zones which are needed should be
mapped.

EXAMPLE - Overlaid Blockage Zones:

A ship has a Sea Tel antenna mounted on the center line of the ship.

A mast mounted on top of a deckhouse (like the picture below) is forward and an engine exhaust stack, also
on a deckhouse, is aft. These two blockage areas have wide azimuth blockage at lower elevations and then a
narrower azimuth area of blockage extends up to a higher value of elevation.

7-1

EAR Controlled - ECCN EAR99