NavCom SF-2110 Rev.C - Manual (Page 45)

SF-2110 User Guide – Rev. C
(which translates into signal strength) throughout
the entire elevation tracking path.
9 Map obstructions above the horizon using a
compass and inclinometer. Use satellite prediction
software with a recent satellite almanac to assess
the impact on satellite visibility at that location
(available on NavCom’s website).
9 A clear line of sight between the antenna and the
local INMARSAT satellite is required to track the
StarFire signal. INMARSAT satellites are geo-
synchronized 35,768kms above the Equator,
currently at Longitudes 15.5
° West, 098° West,
142
° West, 025° East, 109° East, and 143.5°
East. An inclination and bearing estimation tool is
available on NavCom’s website to aid in
determining potential obstructions to StarFire
signal.
‡
StarFire Satellite locations and IDs may
change after September 19, 2008, as
replacement satellites are brought into
service for aging satellites.
L-Band Antenna (SF-2110R Only)
The separate L-band antenna for the SF-2110R is
used in high latitude applications and most frequently
on marine vessels. This is an active antenna,
meaning it has a built-in LNA. Therefore, this antenna
should have good isolation from other near-frequency
antennae. The best practice is to follow the same
precautions as the standard GPS antenna. On
platforms with many antenna systems, it is better to
locate the standard GPS antenna closer to the
wheelhouse, but out of the radar or satcom beam
path and the L-band antenna high on the mast. For
best performance, do not allow more than 7dB of
cable loss between the antenna and the receiver.
* Consult Release Notes on the NavCom web site for availability.
3-43