Meinberg GPS165, Manual

Page: 30 / 62

6.3 Mounting the GPS Antenna
The GPS satellites are not stationary, but circle round the globe with 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/downconverter
unit must be installed in a location that has as clear a view of the sky as possible. The best reception is
achieved 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 the clearest free view to the equator, because the satellite orbits are located
between latitudes 55
◦
North and 55
◦
South. If this is not possible, you may experience difficulty receiving the
four satellites necessary to complete the receiver’s position solution.
The antenna/converter unit can be mounted on a wall, or on a pole up to 60 mm in diameter. A 50 cm
plastic tube, two wall-mount brackets, and clamps for pole mounting are included. A standard RG58 coaxial
cable should be used to connect the antenna/downconverter unit to the receiver. The maximum length of cable
between antenna and receiver depends on the attenuation factor of the coaxial cable.
Up to four GPS165 receivers can be run with one antenna/downconverter unit by using an optional antenna
splitter. The total length of an antenna line from antenna to receiver must not be longer than the max. length
shown in the table below. The position of the splitter in the antenna line does not matter.
The optional delivered MBG S-PRO protection kit can also be used for outdoor installation (degree of protec-
tion: IP55). However, we recommend an indoor installation, as close as possible to the wall where the antenna
cable is entering, to minimize the risk of overvoltage damage, for example by lightning.
6.3.1 Antenna Cable:
Type of cable diameter Ø Attenuation at 100MHz max lenght.
[mm] [dB]/100m [m]
RG58/CU 5mm 17 300
(1)
RG213 10.5mm 7 700
(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
WARNING!
Antenna mounting without effective anti-fall protection
Danger to life due to fall!
- Pay attention to effective working safety when installing antennas!
- Never work without an effective anti-fall equipment!
WARNING!
Working on the antenna system during thunderstorms
Danger to life due to electrical shock!
- Do not carry out any work on the antenna system or the antenna cable
if there is a risk of a lightning strike.
- Do not carry out any work on the antenna system if the safety distance
to free lines and sequential circuits is exceeded.
26 Date: 5th November 2019 GPS165XHS