TD 90227GB
2006-09-18/ Ver. C
System Installation
On Site Paging System
8
activated, the signal on the line is a combination of speech, data, subtone, and quality
tone. The line is not polarized
D-, SP-
b
us
A-, SP-
b
us
1 km
1 km
Re
c
eiver
Interf
ac
e
Fixed
Re
c
eiver
Termin
a
l
Tr
a
nsmitter
Fixed
Re
c
eiver
.
Figure 7. Receivers connected to the Central Unit via the Receiver Interface.
5
Antennas
Several types of antennas are used in the OSP System, such as ground-plane, dipole and
helix antennas but the choice of type should be made to suit the actual site. In some cases
other types of antennas may be required due to the terrain or climatic conditions. Note
that dipoles must be ordered for the correct frequency.
In general, 900-system antennas can be grounded if necessary, but large potential
differences between different ground points can cause problems. Therefore, antenna
grounding should be avoided if possible.
HF
VHF
UHF
25% of
mast height
GP 4103
CXL-2
1,25 m
CXL-70
0,9 m
Wall brackets FM-103
Mast pipes Ø 50 mm x 3 m (2 ea)
0,5 m
0,5 m
2 m
Figure 8. Antenna reliability measures.