Meinberg GPS163AHS, Руководство по эксплуатации

Страница: 10 / 28

10
Installation
Power supply
The variant GPS163DHS is designed for operation with a DC (19 V to 72 V, DC-
insulation 1.5 kV), the type GPS163AHS with an AC (100V to 240V, 47 Hz to 63 Hz)
power supply. The voltage feed is done through terminal blocks in the frontpanel of the
clock and should have low resistance to minimize spurious emission (EMI).
GPS163AHS includes a fuse which is available at the front panel.
To avoid potential differences between the signal ground of GPS163xHS and a
post-connected unit installed on different DIN rails, the signal ground of the clock is
insulated from the case.
The case must be grounded by using the rear contact.
Mounting the 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 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 even this is not
possible problems occure especially when at least four sattelites for positioning have to
be found.
The unit can be mounted using a pole with a diameter up to 60 mm. A standard coaxial
cable with 50
Ω
impedance (e.g. RG58C) should be used to connect the antenna/
converter unit to the receiver. Cable thinner than RG58 should be avoided due to its
higher DC resistance and RF attenuation. When using the optional antenna diplexer the
total length of one antenna line between antenna, diplexer and receiver must not be
longer than 250 m. If a cable with less attenuation is used its length may be increased
accordingly (e.g. 500 m with RG213).