User's Manual Part 2

GPS Antenna Line Loss Chapter 5: Installing the Digital Simulcast Remote Site (10Base-2)
The simulcast system will not operate properly if the GPS receiver is not locked onto at
least four GPS satellites. The four satellites are used to establish a three-dimensional
fix (latitude, longitude, and altitude) for the site.
The TRAK 9100 will free-run for a time period defined by configuration settings. However,
after the specified period while still operating without the GPS satellite signals, the simulcast
system will not operate. The GPS antennas must be properly positioned, and the cables and
connectors must be properly maintained to ensure operation of the simulcast system.
If the TRAK 9100 is powered down, the simulcast system will not operate properly until
the GPS receiver has locked onto the signals from at least four GPS satellites. This
process takes approximately 13 to 25 minutes to complete.
GPS Antenna Line Loss
Cutting the cable below a recommended minimum length can
cause problems with signal strength overload. Refer to Appendix
E in the TRAK 9100 Reference book.
The maximum allowable line attenuation between the antenna and the TRAK 9100 is 6 dB. This
includes a 4 dB margin for attenuation from foliage. Installations in which the antenna has an
unobstructed view of the sky may have a maximum line attenuation of 10 dB.
In a typical installation using 0.5-in., low density foam coaxial cable, the length of the cable run
should never exceed 45.72 m (150 ft). This is sufficient for most installations.
When considering the use of larger cables, calculate the cable lengths allowing 4.5 dB of loss at 1.5 GHz.
The remaining 1.5 dB of attenuation is provided by interior site cabling and connectors.
GPS Antenna Operating Specifications
Table 5-20 lists the operating specifications for the GPS antenna.
Table 5-20 Operating Specifications for the GPS Antenna
Specification
Value or Range
Physical Dimensions Diameter: 8.89 cm (3.5 in.)
Height: 10.16 cm (4.0 cm)
Weight 0.32 kg (0.7 lb) (excluding mast)
Operating Temperature -40º to +85º C (-40º to 185º F)
5-28 68P81003Y71-O November 2002