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Antenna Considerations
The GPS antenna can be installed indoors or outdoors
where an unobstructed view of the sky exists. Rooftops generally make good
locations due to clear overhead sky with views to the horizon, allowing the
antenna to see and track the maximum number of satellites throughout the
day. Installations with obstructed views may prove operational, but may
experience reduced reception quality and the inability to simultaneously
track the maximum number of satellites. In addition to clear sky coverage,
select a site which would not allow the antenna to become buried in drifted
or accumulated snow.
Satellite Visibility
The Star Sync low profile antenna must be mounted with
a full view of the sky. It can view the sky through a window or my mounted
outdoors. More...
Noise Sources
The antenna should be located at least 3 ft from
electromagnetic noise sources such as transmitting antennas.
Cabling
The recommended cable type is RS-232. Avoid sharp
bends in cabling and routing near AC or current carrying wiring.
Serial Cable Length Limits
(RS-232)
Table below lists the maximum permissible cable lengths
for various protocols at various representative data rates. These lengths
are as specified in the EIA RS232C, CCITT V.55 and RS422 interface
standards.
Material requirements:
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Conductor
size and type: 24 AWG, twisted pair.
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Nominal
capacitance: 15.5 picofarads per foot (between
conductors of each pair); 27.5 picofarads per foot (from each conductor to
shield).
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Nominal
DC resistance (each conductor): 24.0 ohms per 1000 feet.
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Nominal
DC resistance (shield): 2.35 ohms per 1000 feet.
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Shield
type: Overall braided with drain wire.
NOTE on RS-232 Serial Cables:
At
lower peripheral speeds of up to 4800 baud, the normal baud rate used in
Star Sync, serial interfaces can usually operate over cables up to 50 feet
long. Use of special high quality cable may in some cases allow this limit
to be extended to as much as 200 feet.
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Plug
the NMEA type data cable from the GPS into the computer’s serial port. The
data cable usually has a female DB-9 connector at the end and plugs into an
available serial port (usually named COM1 or COM2) on the computer. 