Meinberg LANTIME, Operating Instructions Manual

Page: 20 / 153

Mounting the GPS Antenna
The GPS satellites are not stationary but circle round the globe in a period of about
12 hours. They can only be received if no building is in the line-of-sight from the
antenna to the satellite, so the antenna/converter unit must be installed in a location
from which as much of the sky as possible can be seen. The best reception is given
when the antenna has a free view of 8° angular elevation above the horizon. If this is
not possible the antenna should be installed with a mostly free view to the equator
because of the satellite courses which are located between latitudes of 55° North and
55° South. If this is not possible problems occur especially when at least four
satellites for positioning have to be found.
The antenna/converter unit can be mounted on a pole with a diameter up to 60 mm or
on a wall. A 50 cm plastic tube, two holders for wall-mounting and clamps for pole-
mounting are added to every GPS167. A standard coaxial cable with 50
Ω
impedance
should be used to connect the antenna/converter unit to the receiver. The maximum
length of cable between antenna and receiver depends on the attenuation factor of the
used coaxial cable.
Example:
Up to four GPS167 receivers can be run with one antenna/converter unit by using the
optional antenna splitter. The total length of one antenna line between antenna,
splitter and receiver must not be longer than the max. length shown in the table above.
The position of the splitter in the antenna line does not matter. When installing the
high voltage protector CN-UB/E (CN-UB-280DC) be aware to set it directly after
reaching indoor. The CN-UB/E is not for outdoor usage.
20
Type of cable diameter
Ø [mm] Attenuation at 100MHz
[dB]/100m
max. lenght
[m]
RG58/CU 5mm 15.9 300
1
RG213 10.5mm 6.9 700
1
1)This specifications are made for antenna/converter units produced after January, 2005
The values are typically ones; the exact ones are to find out from the data sheet of the
used cable.