Installing the Device
2.5 Connecting a GPS Antenna
line to protect the receiver and connected devices. If a lightning arrestor is installed,
it is important to make sure it has a low impedance path to ground.
To promote signal reception and avoid signal saturation at the receiver input, the
overall GPS system requires a relative gain between 5 and 18 dBi.
Use only low loss, 50 Ω coaxial cabling when connecting the GPS and any other
optional components to the RUGGEDCOM RSG2288.
Note
Using any length of coaxial cable will add some time delay to the GPS signal,
which degrades the accuracy of the calculated time and position. The time delay is
dependent on the type of dielectric material in the cable and ranges from 1 to 2 ns/ft.
The table below gives some examples of the delay that can be expected based on the
dielectric type.
Dielectric Type
Time Delay (ns/ft)
Propagation Velocity (% of c)
Solid Polyethylene (PE)
1.54
65.9
Foam Polyethylene (FE)
1.27
80.0
Foam Polystyrene (FS)
1.12
91.0
Air Space Polyethylene (ASP)
1.15 to 1.21
84 to 88
Solid Teflon (ST)
1.46
69.4
Air Space Teflon (AST)
1.13 to 1.20
85 to 90
To connect a GPS antenna, do the following:
1. Mount the antenna to a pole or wall in an area that provides good signal
coverage and is away from any signal noise emanating from other
communications equipment. Make sure 90° of the sky is visible to the antenna.
IMPORTANT
The lightning arrestor must be installed by a licensed electrician in accordance
with local regulations.
18
RUGGEDCOM RSG2288
Installation Manual, 04/2021, C79000-G8976-1045-17
