FIS HDL1, Operating Manual, Page: 17 / 55

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ANTENNA CONNECTIONS (HDL1-G5 only)
For proper operation, the HDL1-G5 requires that a GPS antenna and a GOES
antenna be connected to the data logger (see Figure 3).
HDL1-G5
DATALOGGER
GOES ANTENNA GND SDI
RAIN SDI
GPS ANTENNA
MAIN
MENU
SOLAR PANEL
BATTERY SDI
SDI
COMPUTER
Figure 3. HDL1-G5 Antenna Connections
GPS ANTENNA
The GPS antenna is used by the HDL1-G5 s internal GOES transmitter to acquire
time synchronization, frequency stability, and location information from the Global
Positioning System. The internal GOES transmitter will not transmit until it has
acquired a GPS fix so it is important that the GPS antenna is mounted securely in a
location where it won t be damaged or covered by snow and where it has adequate
exposure to the sky. The GPS antenna must be the 3.3V active type, and have a
SMA connector for attaching to the HDL1-G5 data logger. FTS supplies two types of
GPS antennas that are suited to particular applications.
The first type is used in applications where snow cover isn t likely to be a problem
and where an electronics cabinet is used to contain the data logger, station power
supply, and other equipment. This antenna is mounted through a hole in the top of
the electronics cabinet and connects to the data logger inside the cabinet using a
short coaxial cable. When installing this antenna, make sure that the antenna seal is
seated properly between the antenna body and the outside cabinet surface before
tightening the antenna s large retaining nut.
The second type of antenna is used in geographic areas that get significant
accumulations of snow. This antenna has a plastic radome that is designed to shed
snow that could cover the antenna and block the GPS signal. For installation of this
type of antenna, a short antenna support arm must first be clamped to a pole such as
a wind sensor mast, or screwed to the side of the building. Next pass the end of the
antenna cable with the TNC connector up through the mounting tube at the outboard
end of the support arm and attach it to the connector on the underside of the
antenna. Finally, screw the antenna down onto the threads on the mounting tube
(hand-tight) and route the cable back to the data logger location using suitable cable
protection and tie straps where appropriate.
Connect the GPS antenna cable to the HDL1-G5 by threading the connector onto the
SMA-Type GPS antenna jack on the HDL1- G5 front panel.
GPS ANTENNA CONNECTOR
(female SMA)
GOES ANTENNA CONNECTOR
(female N type)